ABELMOSCHUS (Family: Malvaceae)

ABELMOSCHUS ESCULENTUS (Linnaeus) Moench - Okra. 2n = (58), (72), (108), (118), 120, (122), 130, (132), (144), (194).

Waste places. From southern Asia or western Africa.

ABIES (Family: Pinaceae)

Abies balsamea (Linnaeus) Miller - Balsam Fir. 2n = 24.

Damp, rich, cool woods, swamps, mountain slopes. [A. balsamea var. phanerolepis Fernald]    CONN herbarium image

ABUTILON (Family: Malvaceae)

ABUTILON PICTUM (Gillies ex Hooker & Arnott) Walpers - Painted Indian-mallow. 2n = 16.

Railroads. From South America. [A. STRIATUM G.F. Dickson ex Lindley]

ABUTILON THEOPHRASTI Medikus - Velvet-leaf. 2n = (28), 42.

Waste places, fields, roadsides. From Eurasia, northern Africa.

ACALYPHA (Family: Euphorbiaceae)

Acalypha gracilens A. Gray - . 2n = 40.

Dry fields, sandy thickets, roadsides, waste places.

Acalypha rhomboidea Rafinesque - . 2n = ?

Fields, roadsides, woodland margins, waste places. [A. virginica misapplied]

Acalypha virginica Linnaeus - . 2n = 40.

Waste places, roadsides, fields, open woodlands, in dry soils.

ACANTHOSPERMUM (Family: Asteraceae)

ACANTHOSPERMUM AUSTRALE (Loefling) Kuntze - Paraguay-bur. 2n = 20, 22.

Waste places. From South America, the Caribbean.

ACER (Family: Sapindaceae)

ACER CAMPESTRE Linnaeus - Hedge Maple. 2n = 26.

Hedgerows, roadsides. From Eurasia, northwestern Africa.

ACER GINNALA Maximowicz - Amur Maple. 2n = 26.

Woodland and field margins, roadsides. From eastern Asia.

Acer negundo Linnaeus var. negundo - Ashleaf Maple. 2n = 26, (42).

Roadsides, waste places, streambanks, alluvial woodlands, railroad margins. [A. NEGUNDO var. VIOLACEUM (G. Kirchner) H. Jaeger]

Acer nigrum F. Michaux - Black Maple. 2n = 26.

Rich, calcareous or alluvial woodlands.

Acer pensylvanicum Linnaeus - Striped Maple. 2n = 26.

Moist, rich woodlands.

ACER PLATANOIDES Linnaeus - Norway Maple. 2n = 26.

Roadsides, hedgerows, waste places, woodland margins. From Eurasia.

ACER PSEUDOPLATANUS Linnaeus - Sycamore Maple. 2n = 52.

Roadsides, fencerows, waste places, woodland margins, streambanks. From Eurasia.

Acer rubrum Linnaeus var. rubrum - Red Maple. 2n = 26, 78, 91, 104.

Acidic woodlands, swamps, alluvial soils, shores, moist fields.

Acer rubrum Linnaeus var. trilobum K. Koch - . 2n = ?

Swamps, low woodlands. [A. rubrum var. tridens Alph. Wood]

Acer saccharinum Linnaeus - Silver Maple. 2n = 52.

Streambanks, alluvial soils, swamps.

Acer saccharum Marshall - Sugar Maple. 2n = 26.

Rich woodlands, especially in calcareous soils.

Acer spicatum Lamarck - Mountain Maple. 2n = 26.

Rich, moist woodlands.

ACER TATARICUM Linnaeus - Tatarian Maple. 2n = 26.

Roadsides. From Eurasia.

Acer hybrid

Acer X freemanii A.E. Murray - .

[A. rubrum Linnaeus X A. saccharinum Linnaeus]

ACHILLEA (Family: Asteraceae)

ACHILLEA FILIPENDULINA Lamarck - Gold Yarrow. 2n = 18, (36), (54).

Clay soil. From the Caucasus and western Asia.

ACHILLEA LIGUSTICA Allioni - Ligurian Yarrow. 2n = 18, (ca. 54).

Roadsides. From the Mediterranean.

Achillea millefolium Linnaeus - Common Yarrow. 2n = (18), (27), 36, (45), 54, (63), (72), (74).

Dry fields, roadsides, waste grounds. [A. borealis Bongard; A. lanulosa Nuttall]

ACHILLEA PTARMICA Linnaeus - Sneezewort. 2n = 18.

Roadsides, fields. From Eurasia.

ACMISPON (Family: Fabaceae)

ACMISPON AMERICANUS (Nuttall) Rydberg var. AMERICANUS - Prairie Trefoil. 2n = 14.

Railroads, waste places. From farther west. [HOSACKIA AMERICANA (Nuttall) Piper; LOTUS AMERICANUS – misapplied; L. PURSHIANUS Clements & E.G. Clements; L. UNIFOLIOLATUS (Hooker) Bentham]

ACONITUM (Family: Ranunculaceae)

ACONITUM NAPELLUS Linnaeus - Garden Monkshood. 2n = (16), 32.

Roadsides, thickets, old house sites. From Europe.

ACONITUM UNCINATUM Linnaeus - Wild Monkshood. 2n = 16.

Waste places. From farther south.

ACONOGONON (Family: Polygonaceae)

ACONOGONON POLYSTACHYUM (Wallich ex Meisner) M. Král - Himalayan Knotweed. 2n = 22.

Moist, waste places. From Asia. [PERSICARIA WALLICHII misapplied; POLYGONUM POLYSTACHYUM Wallich ex Meisner]

ACORUS (Family: Acoraceae)

Acorus americanus (Rafinesque) Rafinesque. - Sweet Flag. 2n = 24.

Marshes, shores, wet meadows. [A. calamus misapplied] [The mapped distribution may include specimens of the introduced sterile triploid, A. CALAMUS, which is not generally distinguished in herbaria.]   NEBC herbarium image

ACORUS CALAMUS Linnaeus - Sweet Flag. 2n = (24), (33), (34), (35), 36, (42), (44), (45), (66).

Marshes, shores, wet meadows. From Europe. [This sterile triploid is not separated from the native species in most herbaria.]   NEBC herbarium image

ACTAEA (Family: Ranunculaceae)

Actaea pachypoda Elliott - White Baneberry. 2n = 16.

Rich woods.

Actaea racemosa Linnaeus - Black Snakeroot. 2n = 16.

Rich, moist woods. [Cimicifuga racemosa (Linnaeus) Nuttall]

Actaea rubra (Aiton) Willdenow - Red Baneberry. 2n = 16.

Rich woods.

Actaea hybrid

Actaea X ludovici B. Boivin - .

[A. pachypoda Elliott X A. rubra (Aiton) Willdenow]

ACTINIDIA (Family: Actinidiaceae)

ACTINIDIA ARGUTA (Siebold & Zuccarini) Planchon ex Miquel - Hardy Kiwi. 2n = 116.

Roadsides, woodland margins. From eastern Asia.

ADIANTUM (Family: Pteridaceae)

Adiantum aleuticum (Ruprecht) C.A. Paris - Aleutian Maidenhair Fern. 2n = 58.

Serpentine barrens. [A. pedatum Linnaeus var. aleuticum Ruprecht; A. pedatum subsp. calderi Cody]   NHA herbarium image

Adiantum pedatum Linnaeus - Common Maidenhair Fern. 2n = (44), 58, (60), (87), (118), (120).

Rich, deciduous woods, in circumneutral or basic soil.   CONN herbarium image

Adiantum viridimontanum C.A. Paris - . 2n = 116.

Serpentine rocks.   KHD herbarium image

ADLUMIA (Family: Papaveraceae)

Adlumia fungosa (Aiton) Greene ex Britton, Sterns & Poggenberg - Climbing Fumitory. 2n = 32.

Moist ledges, moist, rocky woods.

AEGOPODIUM (Family: Apiaceae)

AEGOPODIUM PODAGRARIA Linnaeus - Goutweed. 2n = 22, (38), (39), 42, 44.

Roadsides, waste places, open woodlands, often in moist shade. From Eurasia.

AESCULUS (Family: Sapindaceae)

AESCULUS GLABRA Willdenow var. GLABRA - Ohio Buckeye. 2n = 40.

Woodlands. From farther west and south.

AESCULUS HIPPOCASTANUM Linnaeus - Horse-chestnut. 2n = 40.

Roadsides, waste places, woodland margins. From southeastern Europe.

AETHUSA (Family: Apiaceae)

AETHUSA CYNAPIUM Linnaeus - Fool’s-parsley. 2n = 20, (22).

Roadsides, waste places. From Eurasia.

AGALINIS (Family: Orobanchaceae)

Agalinis decemloba (Greene) Pennell - . 2n = 26, 52.

Fields, woodland openings, roadsides, usually in dry, sandy soil. [A. acuta Pennell; Gerardia acuta Pennell]

Agalinis maritima (Rafinesque) Rafinesque var. maritima - . 2n = 26, 28.

Salt marshes. [Gerardia maritima Rafinesque var. maritima]

Agalinis neoscotica (Greene) Fernald - . 2n = 28.

Damp sand or marshy mudflats near the sea. [A. purpurea (Linnaeus) Pennell var. neoscotica (Greene) B. Boivin; Gerardia neoscotica Greene]

Agalinis purpurea (Linnaeus) Pennell var. purpurea - . 2n = 28.

Swampy fields, meadows, salt marsh margins, dune hollows. [Gerardia purpurea Linnaeus]

Agalinis purpurea (Linnaeus) Pennell var. parviflora (Bentham) B. Boivin - . 2n = 26, 28.

Meadows, wet fields, swamps, shores, bogs, damp, open ground. [A. paupercula (A. Gray) Britton var. paupercula; A. paupercula var. borealis Pennell; Gerardia paupercula (A. Gray) Britton var. paupercula; G. paupercula var. borealis (Pennell) Deam; G. purpurea Linnaeus var. parviflora Bentham]

Agalinis tenuifolia (Vahl) Rafinesque - . 2n = 26, 28.

Woodland openings, fields, thickets, roadsides, usually in dry soil. [A. tenuifolia var. macrophylla (Bentham) S.F. Blake; A. tenuifolia var. parviflora (Nuttall) Pennell; Gerardia tenuifolia Vahl var. tenuifolia; G. tenuifolia var. macrophylla Bentham; G. tenuifolia var. parviflora Nuttall]

Agalinis hybrid

Agalinis purpurea (Linnaeus) Pennell var. parviflora (Bentham) B. Boivin X A. tenuifolia (Vahl) Rafinesque - .

AGASTACHE (Family: Lamiaceae)

AGASTACHE FOENICULUM (Pursh) Kuntze - Blue Giant Hyssop. 2n = 18.

Waste places, woodland margins, fields. From farther west.

Agastache nepetoides (Linnaeus) Kuntze - Yellow Giant Hyssop. 2n = 18.

Roadsides, thickets, open woodlands.

Agastache scrophulariifolia (Willdenow) Kuntze - Purple Giant Hyssop. 2n = 18.

Thickets, rich, open woodlands, streambanks, roadsides. [A. scrophulariifolia var. mollis (Fernald) A. Heller]

AGERATINA (Family: Asteraceae)

Ageratina altissima (Linnaeus) R.M. King & H. Robinson var. altissima - White Snakeroot. 2n = 34, (58).

Rich, moist woods, especially along rivers. [Eupatorium rugosum Houttuyn]

Ageratina aromatica (Linnaeus) Spach - Smaller White Snakeroot. 2n = 34.

Dry, open woods, clearings, thickets. [Eupatorium aromaticum Linnaeus]

AGERATUM (Family: Asteraceae)

AGERATUM CONYZOIDES Linnaeus - Billygoat-weed. 2n = 20, (30), (32), (36), (38), 40.

Waste ground. From South America.

AGERATUM HOUSTONIANUM Miller - Bluemink. 2n = 20, (40).

Disturbed sites. From southeastern Mexico and Central America.

AGRIMONIA (Family: Rosaceae)

AGRIMONIA EUPATORIA Linnaeus - Church Steeples. 2n = 28, (56).

Waste places, fields. From Eurasia, northern Africa.

Agrimonia gryposepala Wallroth - . 2n = 56.

Thickets, deciduous or mixed woods, roadsides.

Agrimonia microcarpa Wallroth - . 2n = ?

Rocky woods.

Agrimonia parviflora Aiton - . 2n = 28.

Calcareous river thickets, riverbanks, meadows, moist woods in circumneutral soil, moist, sandy roadsides.

Agrimonia pubescens Wallroth - . 2n = 28.

Rich, open, deciduous or mixed woods, swamps. [A. bicknellii (Kearney) Rydberg; A. mollis (Torrey & A. Gray) Britton; A. mollis var. bicknellii Kearney]

Agrimonia rostellata Wallroth - Woodland Agrimony. 2n = 28.

Dry, open, rocky woods.

Agrimonia striata Michaux - . 2n = 28, 56.

Thickets, woodland borders, woods.

AGROPYRON (Family: Poaceae)

AGROPYRON CRISTATUM (Linnaeus) Gaertner subsp. CRISTATUM - Crested Wheatgrass. 2n = 14, (21), 28, (42).

Waste places. From Eurasia.

AGROPYRON DESERTORUM (Fischer ex Link) Schultes - . 2n = (14), 28.

Waste places. From Eurasia.

AGROSTEMMA (Family: Caryophyllaceae)

AGROSTEMMA GITHAGO Linnaeus var. GITHAGO - Common Corn-cockle. 2n = (24), 48.

Waste places, fields, roadsides. From Eurasia, northern Africa.

AGROSTIS (Family: Poaceae)

AGROSTIS CANINA Linnaeus. - Velvet Bent. 2n = 14, (16), 28, (35), (42), (56).

Fields, meadows, hillsides. From Europe.

AGROSTIS CAPILLARIS Linnaeus - Rhode Island Bent. 2n = 28, (42).

Fields, pastures, roadsides, thickets, riverbanks. From Europe. [A. TENUIS Sibthorp; A. TENUIS var. ARISTATA (Parnell) Druce]

AGROSTIS ELLIOTTIANA Schultes - . 2n = 28.

Fields, roadsides. From farther south.

AGROSTIS EXARATA Trinius - Spike Bent. 2n = (28), 42, (56).

Clearings in woods along dirt roads. From western North America. [A. EXARATA var. MONOLEPIS (Torrey) Hitchcock]

AGROSTIS GIGANTEA Roth - Redtop. 2n = (28), (34), 42.

Riverbanks, meadows, fields, shores, moist places. From Europe. [A. ALBA - misapplied; A. STOLONIFERA Linnaeus var. MAJOR (Gaudin) Farwell]

Agrostis hyemalis (Walter) Britton, Sterns & Poggenburg - Ticklegrass. 2n = 14, 28, 42.

Dry fields, open woods.

Agrostis mertensii Trinius - . 2n = (41), (42), (49), (50), (55), 56.

Mountain ledges. [A. borealis Hartman var. borealis; A. borealis var. americana (Scribner) Fernald]

Agrostis perennans (Walter) Tuckerman - Autumn Bent. 2n = 28, 42.

Open woods, thickets, dryish open soil. [A. perennans var. aestivalis Vasey; A. perennans var. elata (Pursh) Hitchcock; A. altissima (Walter) Tuckerman]

Agrostis scabra Willdenow - Fly-away Grass. 2n = (35), 42.

Roadsides, sterile, open soil (dry or wet). [A. scabra var. geminata (Trinius) Swallen; A. scabra var. septentrionalis Fernald; A. geminata Trinius; A. hyemalis (Walter) Britton, Sterns & Poggenburg var. scabra (Willdenow) H.L. Blomquist; A. hyemalis var. tenuis (Tuckerman) Gleason]

AGROSTIS STOLONIFERA Linnaeus var. PALUSTRIS (Hudson) Farwell - Creeping Bent. 2n = 28.

Shores, marshes, shallow water. From Europe. [A. STOLONIFERA var. COMPACTA Hartman; A. ALBA Linnaeus var. PALUSTRIS (Hudson) Persoon; A. PALUSTRIS Hudson]

AILANTHUS (Family: Simaroubaceae)

AILANTHUS ALTISSIMA (Miller) Swingle - Tree-of-heaven. 2n = 64, 80.

Roadsides, waste places, woodland margins, fields. From China, Taiwan.

AIRA (Family: Poaceae)

AIRA CARYOPHYLLEA Linnaeus var. CARYOPHYLLEA - Silver Hairgrass. 2n = 14, 28.

Dry sand, waste places. From Europe.

AIRA PRAECOX Linnaeus - . 2n = 14.

Sandy fields. From Europe.

AJUGA (Family: Lamiaceae)

AJUGA GENEVENSIS Linnaeus - . 2n = 32.

Fields, waste places, roadsides, dry ledge outcrops, usually in calcareous soil. From Eurasia.

AJUGA REPTANS Linnaeus - . 2n = 32, (64).

Moist shade, roadsides, fields, wet meadows, woodland margins. From Eurasia, northwestern Africa.

AKEBIA (Family: Lardizabalaceae)

AKEBIA QUINATA (Houttuyn) Decaisne - Chocolate Vine. 2n = 16, 32.

Waste places, roadsides. From eastern Asia.

Akebia hybrid

AKEBIA X PENTAPHYLLA (Makino) Makino - .

[A. QUINATA (Houttuyn) Decaisne X A. TRIFOLIATA (Thunberg) Koidzumi]

ALBIZIA (Family: Fabaceae)

ALBIZIA JULIBRISSIN Durazzini - Silk-tree. 2n = 26, (52).

Waste places. From Asia.

ALCEA (Family: Malvaceae)

ALCEA ROSEA Linnaeus - Hollyhock. 2n = (26), (40), 42, (56), (84).

Waste places, roadsides, railroads, rocky beaches. From southwestern China. [ALTHAEA ROSEA (Linnaeus) Cavanilles]

ALCHEMILLA (Family: Rosaceae)

ALCHEMILLA FILICAULIS Buser subsp. VESTITA (Buser) M.E. Bradshaw - . 2n = ca. 96.

Wool waste. From Europe. [A. VULGARIS Linnaeus var. VESTITA (Buser) Fernald & Wiegand]

ALCHEMILLA MONTICOLA Opiz - . 2n = 101-110.

Woods, fields, roadsides. From Eurasia. [A. PRATENSIS – misapplied; A. VULGARIS – misapplied]

ALETRIS (Family: Nartheciaceae)

Aletris farinosa Linnaeus - Unicorn-root. 2n = 26.

Moist, open, sandy soil and barrens.

ALISMA (Family: Alismataceae)

Alisma gramineum Lejeune - . 2n = 14.

Muddy shores and shallow water of basic lakes or streams.   NEBC herbarium image

Alisma subcordatum Rafinesque - Southern Water-plantain. 2n = 14, 28.

Muddy or sandy shores, marshes, ditches, shallow water. [A. plantago-aquatica Linnaeus var. parviflorum (Pursh) Torrey - illegitimate name]   NEBC herbarium image

Alisma triviale Pursh - Northern Water-plantain. 2n = (14), 28.

Muddy shores, marshes, ditches, shallow water. [A. plantago-aquatica Linnaeus var. americana Schultes & Schultes (son)]   NEBC herbarium image

ALKEKENGI (Family: Solanaceae)

ALKEKENGI OFFICINARUM Moench - Chinese-lantern. 2n = 24, (48).

Waste places, roadsides, thickets, railroads. From Eurasia. [PHYSALIS ALKEKENGI Linnaeus]

ALLIARIA (Family: Brassicaceae)

ALLIARIA PETIOLATA (M. Bieberstein) Cavara & Grande - Garlic Mustard. 2n = (14), (36), 42.

Shaded roadsides, waste places, fields, thin woods. From Eurasia, northern Africa. [A. OFFICINALIS Andrzejowski ex M. Bieberstein - illegitimate name]

ALLIUM (Family: Amaryllidaceae)

Allium canadense Linnaeus var. canadense - Wild Garlic. 2n = (14), (16), (21), 28, (82).

Low woods, alluvial thickets, meadows.    CONN herbarium image

ALLIUM CEPA Linnaeus - Onion. 2n = (14), 16, (24), (28), (32).

Waste ground. From southwest Asia.    CONN herbarium image

ALLIUM OLERACEUM Linnaeus - Wild Onion. 2n = (24), 32, 40, (48).

Wood borders, thickets, roadside banks. From Europe.    MASS herbarium image

ALLIUM SATIVUM Linnaeus - Garlic. 2n = (12), 16, (48).

Roadsides, pastures, fields. From western Asia.    MASS herbarium image

Allium schoenoprasum Linnaeus - Chives. 2n = 16, 16 + (1-18)B, (24), (32), (48).

Gravelly and rocky shores [A. schoenoprasum var. sibiricum (Linnaeus) Hartman]    CONN herbarium image

Allium tricoccum Aiton var. tricoccum - Wild Leek. 2n = 16.

Rich, basic woods and bottoms.    CONN herbarium image

ALLIUM TUBEROSUM Rottler ex Sprengel - Garlic Chives. 2n = (16), (24), (31), 32, (33), (64).

Waste places, fields. From southeastern Asia.    NEBC herbarium image

ALLIUM VINEALE Linnaeus - Field Garlic. 2n = (16), 32, (40), (48).

Dry grasslands, fallow fields, waste places. From Europe.    GH herbarium image

ALNUS (Family: Betulaceae)

ALNUS GLUTINOSA (Linnaeus) Gaertner - Black Alder. 2n = 28, (56).

Damp thickets, stream banks. From Europe.

Alnus incana (Linnaeus) Moench subsp. rugosa (Du Roi) R.T. Clausen - Speckled Alder. 2n = 28.

Swamps, stream margins, lake shores, low grounds. [A. rugosa (Du Roi) Sprengel var. americana (Regel) Fernald]

Alnus serrulata (Aiton) Willdenow - Smooth Alder. 2n = 28.

Swamps, stream margins, lake shores, low grounds.

Alnus viridis (Chaix) de Candolle subsp. crispa (Aiton) Turrill - Green Alder. 2n = 28.

Stream banks, swamps. [A. crispa (Aiton) Pursh; A. crispa (Aiton) Pursh var. mollis (Fernald) Fernald]

Alnus hybrids

Alnus X fallacina Callier - .

[Alnus incana Moench subsp. rugosa (Du Roi) R.T. Clausen X A. serrulata (Aiton) Willdenow; A. serrulata (Aiton) Willdenow var. subelliptica Fernald]

ALNUS GLUTINOSA (Linnaeus) Gaertner X A. serrulata (Aiton) Willdenow - .

ALOPECURUS (Family: Poaceae)

Alopecurus aequalis Sobolewski var. aequalis - . 2n = 14, (28).

Shallow water, shores, meadows, ditches. [A. aequalis var. natans (Wahlenberg) Fernald]

ALOPECURUS CAROLINIANUS Walter - . 2n = 14, 28.

Fields. From farther west and south.

ALOPECURUS GENICULATUS Linnaeus var. GENICULATUS - Marsh Foxtail. 2n = (14), 28.

Wet roadsides, ditches, shallow water. From Eurasia.

ALOPECURUS MYOSUROIDES Hudson - Slender Foxtail. 2n = 14, (28).

Fields, waste places. From Europe.

ALOPECURUS PRATENSIS Linnaeus - Meadow Foxtail. 2n = 28.

Fields, meadows, roadsides. From Eurasia.

ALTERNANTHERA (Family: Amaranthaceae)

ALTERNANTHERA PUNGENS Kunth - Khakiweed. 2n = 64, 68

Waste places. From West Indies, South America.

ALTHAEA (Family: Malvaceae)

ALTHAEA OFFICINALIS Linnaeus - Marsh-mallow. 2n = (40), 42.

Salt or brackish marsh margins, waste places. From Eurasia, northern Africa.

ALYSSUM (Family: Brassicaceae)

ALYSSUM ALYSSOIDES (Linnaeus) Linnaeus - Pale Madwort. 2n = (16), (24), 32.

Dry fields, roadsides, waste places. From Eurasia, northern Africa.

AMARANTHUS (Family: Amaranthaceae)

AMARANTHUS ALBUS Linnaeus - Tumbleweed. 2n = 32, (34).

Waste places, disturbed ground, roadsides. From tropical America. [A. GRAECIZANS - misapplied]

AMARANTHUS BLITOIDES S. Watson - Matweed. 2n = 32.

Waste places, disturbed ground, roadsides. From farther west. [A. GRAECIZANS - misapplied]

AMARANTHUS BLITUM Linnaeus - Purple Amaranth. 2n = 34.

Waste places. From tropical America, Eurasia, Africa. [A. ASCENDENS Loiseleur; A. LIVIDUS Linnaeus]

Amaranthus cannabinus (Linnaeus) J.D. Sauer - Saltmarsh Hemp. 2n = ?

Tidal shores of rivers, salt marshes. [Acnida cannabina Linnaeus]

AMARANTHUS CAUDATUS Linnaeus - Love-lies-bleeding. 2n = 32, (34), (64).

Waste places. From tropical America.

AMARANTHUS CRUENTUS Linnaeus - Blood Amaranth. 2n = (30), 32, 34.

Waste places, roadsides. From Central America.

AMARANTHUS DEFLEXUS Linnaeus - Argentina Amaranth. 2n = 34.

Waste places. From South America.

Amaranthus hybridus Linnaeus - Smooth Amaranth. 2n = (17), 32, (33), (34).

Waste places, fallow fields, roadsides, disturbed ground.

AMARANTHUS HYPOCHONDRIACUS Linnaeus - Prince's-feather. 2n = (16), 32, (34), (64).

Near cultivated places. From cultivation in southwestern North America.

AMARANTHUS PALMERI S. Watson - Palmer's Amaranth. 2n = 34.

Waste places near woolen mills, railroads. From farther southwest.

AMARANTHUS POWELLII S. Watson - Powell's Amaranth. 2n = (32), 34.

Waste places. From farther west.

Amaranthus pumilus Rafinesque - Sea-beach Amaranth. 2n = ?

Sea beaches, mostly on foredunes at high tide level.

Amaranthus retroflexus Linnaeus - Redroot. 2n = (32), 34.

Roadsides, waste places, disturbed ground.

AMARANTHUS SPINOSUS Linnaeus - Thorny Amaranth. 2n = 34.

Waste places. From tropical America.

AMARANTHUS TUBERCULATUS (Moquin-Tandon ex de Candolle) J.D. Sauer - Tall Water-hemp. 2n = 32.

Waste places. From farther west. [A. TUBERCULATUS var. PROSTRATUS (Uline & W.L. Bray) F. Seymour; A. TUBERCULATUS var. SUBNUDUS (S. Watson) Mohlenbrock; A. RUDIS J.D. Sauer; ACNIDA ALTISSIMA Riddell ex Moquin-Tandon - illegitimate name; A. ALTISSIMA var. PROSTRATA (Uline & W.L. Bray) Fernald]

AMARANTHUS VIRIDIS Linnaeus - Green Amaranth. 2n = 34.

Waste places. From South America. [A. GRACILIS Desfontaines ex Poiret]

Amaranthus hybrids

Amaranthus hybridus Linnaeus X A. TUBERCULATUS (Moquin-Tandon) J.D. Sauer - .

Amaranthus retroflexus Linnaeus X A. TUBERCULATUS (Moquin-Tandon) J.D. Sauer - .

AMBROSIA (Family: Asteraceae)

Ambrosia artemisiifolia Linnaeus - Common Ragweed. 2n = (28), (34), 36.

Waste areas, roadsides, fields. [A. artemisiifolia var. elatior (Linnaeus) Descourtilz; A. artemisiifolia var. paniculata (Michaux) Blankinship]

Ambrosia bidentata Michaux - Southern Ragweed. 2n = 34.

Waste ground.

AMBROSIA PSILOSTACHYA de Candolle - Western Ragweed. 2n = (36), (54), 72, (108), (144).

Railroads, waste places, dry fields. From farther west. [A. PSILOSTACHYA var. CORONOPIFOLIA (Torrey & A. Gray) Farwell]

Ambrosia trifida Linnaeus - Great Ragweed. 2n = 24, (30).

Waste places, railroads, rich, damp soil. [A. trifida var. texana Scheele]

Ambrosia hybrid

Ambrosia X helenae Rouleau - .

[A. artemisiifolia Linnaeus X A. trifida Linnaeus]

AMELANCHIER (Family: Rosaceae)

Amelanchier arborea (F. Michaux) Fernald - Downy Shadbush. 2n = 34, 68.

Rocky, upland or dry, rich woods, thickets.

Amelanchier bartramiana (Tausch) M. Roemer - Mountain Shadbush. 2n = 32, 50, 68.

Cold swamps, bogs, moist thickets, cool woods, bushy slopes, mountain summits.

Amelanchier canadensis (Linnaeus) Medikus var. canadensis - Eastern Shadbush. 2n = 34, 68.

Woods, moist thickets, swamps, marsh borders. [A. oblongifolia (Torrey & A. Gray) M. Roemer var. oblongifolia]

Amelanchier gaspensis (Wiegand) Fernald & Weatherby - . 2n = 68.

River shores and their outcrops.

Amelanchier humilis Wiegand - 2n = 34, 68.

Calcareous ledges.

Amelanchier interior E.L. Nielsen - . 2n = 72.

Rocky slopes, stream banks, sandy areas. [A. wiegandii E.L. Nielson]

Amelanchier intermedia Spach - 2n = 34, 56.

Swamps, bogs, thickets, shores.

Amelanchier laevis Wiegand - Smooth Shadbush. 2n = 30, 36, 68.

Woodland borders, damp thickets, fields, roadsides.

Amelanchier nantucketensis E.P. Bicknell - . 2n = 68.

Dry fields, sandy grasslands, heaths, pine barrens, pond and river shores among rocks or in sand. [A. canadensis (Linnaeus) Medikus var. micropetala (B.L. Robinson) Rehder; A. oblongifolia (Torrey & A. Gray) M. Roemer var. micropetala B.L. Robinson]

Amelanchier sanguinea (Pursh) de Candolle - Red-twigged Shadbush. 2n = 34, 40.

Riverbanks, ledges, woodland borders.

Amelanchier spicata (Lamarck) K. Koch - Thicket Shadbush. 2n = (34), (56), 68.

Rocky or sandy, open habitats, typically in acidic soil. [A. stolonifera Wiegand]

Amelanchier hybrids

Amelanchier arborea (F. Michaux) Fernald X A. bartramiana (Tausch) M. Roemer - .

Amelanchier arborea (F. Michaux) Fernald X A. laevis Wiegand - .

Amelanchier arborea (F. Michaux) Fernald X A. spicata (Lamarck) K. Koch - .

Amelanchier bartramiana (Tausch) M. Roemer X A. canadensis (Linnaeus) Medikus - .

Amelanchier bartramiana (Tausch) M. Roemer X A. laevis Wiegand - .

[A. X neglecta Eggleston ex G.N. Jones (pro species - invalid namme ]

Amelanchier bartramiana (Tausch) M. Roemer X A. spicata (Lamarck) K. Koch - .

Amelanchier canadensis Medikus X A. laevis Wiegand - .

Amelanchier canadensis Medikus X A. spicata (Lamarck) K. Koch - .

Amelanchier humilis Wiegand X A. laevis Wiegand - .

Amelanchier laevis Wiegand X A. sanguinea (Pursh) de Candolle - .

Amelanchier laevis Wiegand X A. spicata (Lamarck) K. Koch - .

Amelanchier sanguinea (Pursh) de Candolle X A. spicata (Lamarck) K. Koch - .

AMERORCHIS (Family: Orchidaceae)

Amerorchis rotundifolia (Banks ex Pursh) Hultén - Small Round-leaved Orchis. 2n = 42.

Bogs, swamps, boggy woods, in basic soil. [Orchis rotundifolia Banks ex Pursh]

AMMOPHILA (Family: Poaceae)

Ammophila breviligulata Fernald subsp. breviligulata - Beachgrass. 2n = 28.

Sand dunes. [A. arenaria misapplied]

Ammophila breviligulata Fernald subsp. champlainensis (F. Seymour) P.J. Walker, C.A. Paris & Barrington ex Barkworth - Champlain Beachgrass. 2n = ?

Shores of fresh water lakes.

AMORPHA (Family: Fabaceae)

AMORPHA FRUTICOSA Linnaeus - False Indigo. 2n = 38, 40.

Roadsides, thickets, waste places. From farther south and west. [A. FRUTICOSA var. OBLONGIFOLIA E.J. Palmer]

AMPELOPSIS (Family: Vitaceae)

AMPELOPSIS CORDATA Michaux - Raccoon-grape. 2n = 40.

Roadside thickets, salt marsh margins, sandy waste places. From farther south and west.

AMPELOPSIS GLANDULOSA (Wallich) Momiyama - Porcelain-berry. 2n = 40.

Roadsides, thickets, woodlands, waste places. From China. [A. GLANDULOSA var. BREVIPEDUNCULATA (Maximowicz) Momiyama; A. BREVIPEDUNCULATA (Maximowicz) Trautvetter]

AMPHICARPAEA (Family: Fabaceae)

Amphicarpaea bracteata (Linnaeus) Fernald var. bracteata - Hog-peanut. 2n = 20, 22, 40.

Rich woods, thickets. [A. monoica Nuttall - illegitimate name]

Amphicarpaea bracteata (Linnaeus) Fernald var. comosa (Linnaeus) Fernald - Pitcher's Hog-peanut. 2n = 22.

Rich woods, thickets.

AMPHICARPUM (Family: Poaceae)

Amphicarpum amphicarpon (Pursh) Nash - . 2n = 18.

Kettlehole ponds, roadsides. [A. purshii Kunth]

AMSINCKIA (Family: Boraginaceae)

AMSINCKIA EASTWOODIAE J.F. Macbride - . 2n = 24.

Moist ledges. From California. [A. INTERMEDIA Fischer & C.A. Meyer var. EASTWOODIAE (J.F. Macbride) Jepson & Hoover]

AMSINCKIA INTERMEDIA Fischer & C.A. Meyer - Common Fiddleneck. 2n = 15, 30, 34, 38.

Wool waste, roadsides, grassy hills. From western North America. [A. MENZIESII (Lehmann) A. Nelson & J.F. Macbride var. INTERMEDIA (Fischer & C.A. Meyer) Ganders - illegitimate name]

AMSINCKIA LYCOPSOIDES Lehmann - Bugloss Fiddleneck. 2n = 30.

Railroads, waste places. From western North America. [A. BARBATA Greene]

AMSINCKIA MENZIESII (Lehmann) A. Nelson & J.F. Macbride - Rancher’s Fiddleneck. 2n = 34.

Wool waste, roadsides. From western North America.

AMSONIA (Family: Apocynaceae)

AMSONIA TABERNAEMONTANA Walter var. TABERNAEMONTANA - Eastern Bluestar. 2n = 22, 32.

Waste places. From farther south and west.

ANAPHALIS (Family: Asteraceae)

Anaphalis margaritacea (Linnaeus) Bentham & Hooker (son) - Pearly Everlasting. 2n = 28, (42), (56).

Dry woods, clearings, fields, roadsides. [A. margaritacea var. angustior (Miquel) Nakai; A. margaritacea var. intercedens H. Hara; A. margaritacea var. subalpina (A. Gray) A. Gray]

ANCHUSA (Family: Boraginaceae)

ANCHUSA ARVENSIS (Linnaeus) M. von Bieberstein - Small Bugloss. 2n = 48, (ca. 54).

Sandy fields, waste places, railroads, wool waste. From Europe. [LYCOPSIS ARVENSIS Linnaeus]

ANCHUSA AZUREA Miller - Italian Bugloss. 2n = 32.

Waste places, field margins, roadsides. From Eurasia, northern Africa.

ANCHUSA LEPTOPHYLLA Roemer & Schultes subsp. LEPTOPHYLLA - . 2n = 16, 32, 33.

Waste places. From Eurasia.

ANCHUSA OFFICINALIS Linnaeus - Common Bugloss. 2n = 16.

Waste places, roadsides. From Europe.

ANDERSONGLOSSUM (Family: Boraginaceae)

Andersonglossum boreale (Fernald) Jim. Mejias, j.I. Cohen & Naczi - Northern Wild Comfrey. 2n = 24.

Rich, open woodlands. [Cynoglossum boreale Fernald; C. virginianum Linnaeus var. boreale (Fernald Cooperrider)]

Andersonglossum virginianum (Linnaeus) J.I. Cohen - Wild Comfrey. 2n = ?

Open, deciduous or mixed woodlands. [Cynoglossum virginianum Linnaeus var. virginianum]

ANDROMEDA (Family: Ericaceae)

Andromeda polifolia Linnaeus var. latifolia Aiton - Bog Rosemary. 2n = 48.

Sphagnum bogs. [A. polifolia var. glaucophylla (Link) de Candolle; A. glaucophylla Link]

ANDROPOGON (Family: Poaceae)

Andropogon gerardi Vitman subsp. gerardi - Big Bluestem. 2n = 40, 60, 68, 70, 80, 90.

Dry, open ground. [A. gerardii var. chrysocomus (Nash) Fernald]

Andropogon glomeratus (Walter) Britton, Sterns & Poggenburg var. glomeratus - Bushy Beardgrass. 2n = 20.

Boggy or other wet soils. [A. virginicus Linnaeus var. abbreviatus (Hackel) Fernald & Griscom]

Andropogon virginicus Linnaeus var. virginicus - Broom-sedge. 2n = 20.

Dry, open soil, thin woods, upper shores of ponds.

ANDROSACE (Family: Primulaceae)

ANDROSACE OCCIDENTALIS Pursh - Western Rock-jasmine. 2n = 20.

Waste places. From farther west.

ANEMONE (Family: Ranunculaceae)

ANEMONE BLANDA Schott & Kotschy - Grecian Windflower. 2n = (14), 16, (32).

Disturbed woods. From Europe.

Anemone canadensis Linnaeus - Canada Anemone. 2n = 14.

Damp thickets, woodland margins, meadows, riverbanks, shores.

Anemone cylindrica A. Gray - Long-headed Anemone. 2n = 16.

Dry, open soil, roadsides.

Anemone multifida Poiret var. multifida - Cut-leaved Anemone. 2n = (16), 32, (64).

Calcareous ledges.

ANEMONE NEMOROSA Linnaeus - European Wood Anemone. 2n = (16), (24), (28), 30, (32), (37), (42), (45), (46).

Woods. From Europe.

Anemone quinquefolia Linnaeus var. quinquefolia - Wood Anemone. 2n = 32.

Open, moist woods, woodland borders. [A. quinquefolia var. bifolia Farwell; A. quinquefolia var. interior misapplied]

Anemone virginiana Linnaeus var. virginiana - Tall Anemone. 2n = 16.

Dry, rocky, open woods, thickets, riverbanks.

Anemone virginiana Linnaeus var. alba (Oakes) Alph. Wood - River Thimbleweed. 2n = 16.

Riverbanks, shores. [A. riparia Fernald]

Anemone hybrid

Anemone cylindrica A. Gray X A. virginiana Linnaeus var. virginiana - .

ANETHUM (Family: Apiaceae)

ANETHUM GRAVEOLENS Linnaeus - Dill. 2n = 22, (44).

Roadsides, waste places. Cultivated worldwide, probably from southern Asia.

ANGELICA (Family: Apiaceae)

Angelica atropurpurea Linnaeus - Alexanders. 2n = 22.

Brook and river margins, meadows, rich thickets, swamps, alluvial soil, roadside ditches.

Angelica lucida Linnaeus - Seacoast Angelica. 2n = 22, 28.

Sea beach margins, fields by coastal beaches, rocks along coast. [Coelopleurum lucidum (Linnaeus) Fernald]

Angelica venenosa (J. Greenway) Fernald - Hairy Angelica. 2n = 22.

Woodlands, fields, thickets, openings, in dry soil.

ANODA (Family: Malvaceae)

ANODA CRISTATA (Linnaeus) Schlechtendal - Violettas. 2n = 30, 60.

Wool waste. From farther west, Mexico, Central America, South America, Caribbean.

ANTENNARIA (Family: Asteraceae)

Antennaria howellii Greene subsp. canadensis (Greene) R.J. Bayer - . 2n = 56, 84, ca. 100, ca. 102.

Dry fields, open woods. [A. canadensis Greene]

Antennaria howellii Greene subsp. neodioica (Greene) R.J. Bayer - Smaller Pussytoes. 2n = ca. 52, 56, ca. 62, ca. 68, 70, 84, ca. 94, 98, 100, 112, 140.

Dry fields, open woods. [A. neglecta Greene var. neodioica (Greene) Cronquist; A. neodioica Greene var. neodioica; A. neodioica var. attenuata Fernald; A. neodioica var. chlorophylla Fernald; A. neodioica var. grandis Fernald; A. rupicola Fernald]

Antennaria howellii Greene subsp. petaloidea (Fernald) R.J. Bayer - . 2n = 56, 84, ca. 90, 98, 112.

Dry fields, open woods. [A. neglecta Greene var. petaloidea (Fernald) Cronquist; A. petaloidea (Fernald) Fernald var. petaloidea; A. petaloidea var. scariosa Fernald; A. petaloidea var. subcorymbosa (Fernald) Fernald]

Antennaria neglecta Greene - Field Pussytoes. 2n = 28, (63), (84).

Dry fields, open woods.

Antennaria parlinii Fernald subsp. parlinii - Smooth Pussytoes. 2n = (56), (70), 84, (112).

Dry fields, open woods. [A. parlinii var. arnoglossa (Greene) Fernald; A. plantaginifolia (Linnaeus) Hooker var. arnoglossa (Greene) Cronquist]

Antennaria parlinii Fernald subsp. fallax (Greene) R.J. Bayer & Stebbins - . 2n = (42), 56, 84.

Dry fields, open woods. [A. brainerdii Fernald; A. fallax Greene; A. munda Fernald; A. plantaginifolia (Linnaeus) Hooker var. ambigens (Greene) Cronquist]

Antennaria plantaginifolia (Linnaeus) Hooker - . 2n = 28.

Dry, open woods, fields, rocky banks. [A. plantaginifolia var. petiolata (Fernald) A. Heller]

Antennaria hybrid

Antennaria howellii Greene subsp. petaloidea (Fernald) R.J. Bayer X A. plantaginifolia (Linnaeus) Hooker - .

ANTHEMIS (Family: Asteraceae)

ANTHEMIS ARVENSIS Linnaeus - Corn Chamomile. 2n = 18.

Waste places, fields, roadsides. From Eurasia, northern Africa. [A. ARVENSIS var. AGRESTIS (Wallroth) de Candolle]

ANTHEMIS COTULA Linnaeus - Mayeed. 2n = 18.

Waste places, fields, roadsides. From Eurasia, northern Africa.

ANTHOXANTHUM (Family: Poaceae)

ANTHOXANTHUM ARISTATUM Boissier subsp. ARISTATUM - . 2n = 10, (20).

Waste places. From Europe. [A. PUELII Lecoq & Lamotte]

Anthoxanthum hirtum (Schrank) Y. Schouten & Veldkamp - Sweetgrass. 2n = 10, 56.

Meadows and marshes, not saline or brackish, shores. [Hierochloë odorata (Linnaeus) P. Beauvois -- in part]

Anthoxanthum monticola (Bigelow) Veldkamp subsp. monticola
- Alpine Sweetgrass. 2n = 56, 58, 63.

Siliceous rock and dry peat at high altitudes. [Hierochloë alpina (Swartz ex Willdenow) Roemer & Schultes subsp. orthantha (Sørensen) G. Weim]

Anthoxanthum nitens (Weber) Y. Schouten & Veldkamp subsp. nitens
- Sweetgrass. 2n = 28, (42).

Meadows, salt marshes, roadsides, and fields. [Hierochloë odorata (Linnaeus) P. Beauvois -- in part]

ANTHOXANTHUM ODORATUM Linnaeus subsp. ODORATUM - Sweet Vernal-grass. 2n = 10, (15), 20, (21).

Fields, roadsides, woods, waste places. From Europe.

ANTHRISCUS (Family: Apiaceae)

ANTHRISCUS CEREFOLIUM (Linnaeus) Hoffmann - Garden Chervil. 2n = 18.

Roadsides, waste places. From Eurasia.

ANTHRISCUS SYLVESTRIS (Linnaeus) Hoffman - Wild Chervil. 2n = 16, (32), (48).

Fields, waste places, roadsides. From Eurasia, northern and central Africa.

ANTHYLLIS (Family: Fabaceae)

ANTHYLLIS VULNERARIA Linnaeus - Kidney-vetch. 2n = 12.

Roadsides, waste places, fields. From Eurasia, northern Africa.

ANTICLEA (Family: Melanthiaceae)

Anticlea elegans (Pursh) Rydberg var. glauca (Nuttall) Zomlefer & Judd - White Camass. 2n = 32.

Basic gravel, cliffs, shores, bogs. [Zigadenus elegans Pursh var. glaucus (Nuttall) Preece; Z. glaucus Nuttall]

ANTIRRHINUM (Family: Plantaginaceae)

ANTIRRHINUM MAJUS Linnaeus - Common Snapdragon. 2n = 16, (18), (24), (32), (36), (64).

Waste places. From the Mediterranean.

APERA (Family: Poaceae)

APERA SPICA-VENTI (Linnaeus) P. Beauvois - . 2n = 14.

Waste places. From Europe. [AGROSTIS SPICA-VENTI Linnaeus]

APIOS (Family: Fabaceae)

Apios americana Medikus - Groundnut. 2n = 22, 33, 40.

Riverbanks, rich, moist thickets, primarily along streams and lakes.

APIUM (Family: Apiaceae)

APIUM GRAVEOLENS Linnaeus var. DULCE (Miller) de Candolled - Celery. 2n = 22.

Waste places. From Eurasia.

APLECTRUM (Family: Orchidaceae)

Aplectrum hyemale (Muhlenberg ex Willdenow) Torrey - Putty-root. 2n = ?

Rich, rocky woods.

APOCYNUM (Family: Apocynaceae)

Apocynum androsaemifolium Linnaeus - Spreading Dogbane. 2n = 16, 22.

Roadsides, dry fields, thickets, woodland margins.

Apocynum cannabinum Linnaeus - Indian Hemp. 2n = 16, 22.

Shores, thickets, woodland margins, open ground. [A. cannabinum var. pubescens (R. Brown) A. de Candolle; A. sibiricum Jacquin var. sibiricum; A. sibiricum var. cordigerum (Greene) Fernald]

Apocynum hybrid

Apocynum X floribundum Greene (pro sp.) - .

[A. androsaemifolium Linnaeus X A. cannabinum Linnaeus; A. medium Greene]

AQUILEGIA (Family: Ranunculaceae)

Aquilegia canadensis Linnaeus - Wild Columbine. 2n = 14, (16), (32).

Rock outcrops in woods, cliffs, rich soil. [A. canadensis var. coccinea (Small) Munz]

AQUILEGIA VULGARIS Linnaeus - Garden Columbine. 2n = 14, (16), (28), (32).

Roadsides, woodland borders, disturbed areas. From Europe.

ARABIDOPSIS (Family: Brassicaceae)

Arabidopsis lyrata (Linnaeus) O’Kane & Al-Shehbaz subsp. lyrata - Sand Cress. 2n = 16, 32.

Dry ledges (especially basic soil), gravels, sands. [Arabis lyrata Linnaeus]

ARABIDOPSIS THALIANA (Linnaeus) Heynhold - Mouse-ear Cress. 2n = (6), 10, (20).

Sandy roadsides, waste places, dry fields. From Eurasia.

ARABIS (Family: Brassicaceae)

Arabis alpina Linnaeus - Alpine Rock-cress. 2n = 16, (32).

Calcareous rocks, alpine meadows.

ARABIS CAUCASICA Willdenow - Garden Rock-cress. 2n = 16, (24).

Waste places. From southwestern Asia.

Arabis pycnocarpa M. Hopkins var. pycnocarpa - Hairy Rock-cress. 2n = 32.

Dry, calcareous ledges. [A. hirsuta (Linnaeus) Scopoli var. pycnocarpa (M. Hopkins) Rollins]

ARACHIS (Family: Fabaceae)

ARACHIS HYPOGAEA Linnaeus - Common Peanut. 2n = (20), (38), 40.

Roadsides, waste places, fields. From South America.

ARALIA (Family: Araliaceae)

ARALIA ELATA (Miquel) Seemann - Japanese Angelica-tree. 2n = 24.

Roadsides, thickets, streambanks, field margins. From eastern Asia.

Aralia hispida Ventenat - Bristly Sarsaparilla. 2n = 24.

Roadsides, sandy or rocky open woodlands and clearings, in dry soil.

Aralia nudicaulis Linnaeus - Wild Sarsaparilla. 2n = 24, (48).

Woodlands.

Aralia racemosa Linnaeus subsp. racemosa - Spikenard. 2n = 24.

Woodlands, thickets, woodland margins, in rich soil.

ARALIA SPINOSA Linnaeus - Hercules’-club. 2n = 24.

Thickets, roadsides, woodland margins.

ARCEUTHOBIUM (Family: Santalaceae)

Arceuthobium pusillum Peck - Dwarf Mistletoe. 2n = 28.

Parasitic on Picea, rarely on Larix or Pinus strobus.

ARCTIUM (Family: Asteraceae)

ARCTIUM LAPPA Linnaeus - Great Burdock. 2n = (18), (32), (34), 36.

Waste places, roadsides. From Eurasia.

ARCTIUM MINUS (Hill) Bernhardi - Common Burdock. 2n = (18), (32), 36.

Waste places, roadsides. From Eurasia. [A. NEMOROSUM – misapplied; A. VULGARE – misapplied]

ARCTIUM TOMENTOSUM Miller - 2n = 36.

Waste places. From Eurasia.

Arctium hybrid

ARCTIUM LAPPA Linnaeus X A. TOMENTOSUM Miller - .

ARCTOSTAPHYLOS (Family: Ericaceae)

Arctostaphylos uva-ursi (Linnaeus) Sprengel - Common Bearberry. 2n = 26, (39), 52, (72), (78).

Dry, open, sandy or rocky soils. [A. uva-ursi var. coactilis Fernald & J.F. Macbride]

ARCTOTIS (Family: Asteraceae)

ARCTOTIS STOECHADIFOLIA P.J. Bergius - Blue-eyed African-daisy. 2n = 18.

Railroads. From southern Africa. [A. VENUSTA Norlindh]

ARCTOUS (Family: Ericaceae)

Arctous alpina (Linnaeus) Niedenzu - Alpine Bearberry. 2n = 26, (28).

Alpine areas. [Arctostaphylos alpina (Linnaeus) Sprengel]

ARENARIA (Family: Caryophyllaceae)

ARENARIA SERPYLLIFOLIA Linnaeus var. SERPYLLIFOLIA - Thyme-leaved Sandwort. 2n = (10), (20), (22), (30), 40, (44).

Dry ledges, often limestone, dry, sterile fields, roadsides. From Eurasia, northern Africa.

ARENARIA SERPYLLIFOLIA Linnaeus var. TENUIOR Mertens & W.D.J. Koch - Thyme-leaved Sandwort. 2n = 20.

Dry ledges, often limestone, dry, sterile fields, roadsides. From Eurasia, northern Africa.

ARETHUSA (Family: Orchidaceae)

Arethusa bulbosa Linnaeus - Arethusa. 2n = 40.

Sphagnous bogs, meadows, and swamps.

ARGEMONE (Family: Papaveraceae)

ARGEMONE ALBIFLORA Hornemann subsp. ALBIFLORA - White Prickly-poppy. 2n = 28, (56).

Waste places, roadsides. From southeastern United States. [A. ALBA F. Lestiboudois]

ARGEMONE MEXICANA Linnaeus - Mexican Prickly-poppy. 2n = 28, (56), (112).

Waste places. From tropical America and Caribbean islands.

ARISAEMA (Family: Araceae)

Arisaema dracontium (Linnaeus) Schott - Green Dragon. 2n = 28, 56.

Rich or alluvial soil.    VT herbarium image

Arisaema triphyllum (Linnaeus) Schott subsp. triphyllum - Jack-in-the-pulpit. 2n = 28, (36), 56.

Rich, damp to wet woods, boggy places. [A. atrorubens (Aiton) Blume]    CONN herbarium image

Arisaema triphyllum (Linnaeus) Schott subsp. pusillum (Peck) Huttleston - . 2n = ?

Swamps, boggy places, wet, low woodlands. [A. triphyllum var. pusillum Peck; A. pusillum (Peck) Nash] Note: The distribution records do not include those in the NEBC and Harvard University herbaria since this taxon is not currently separated from the typical subspecies in those herbaria.    CONN herbarium image

Arisaema triphyllum (Linnaeus) Schott subsp. stewardsonii (Britton) Huttleston - . 2n = ?

Rich, damp to wet woods, boggy places. [A. triphyllum var. stewardsonii (Britton) Stevens ex Wiegand & Eames; A. stewardsonii Britton] Note: This taxon is not mapped since it is not currently separated from the typical subspecies in the NEBC and Harvard University herbaria.    CONN herbarium image

Arisaema hybrid

Arisaema dracontium (Linnaeus) Schott X A. triphyllum (Linnaeus) Schott - .

ARISTIDA (Family: Poaceae)

Aristida basiramea Engelmann ex Vasey - . 2n = ?

Dry, sandy soil.

Aristida dichotoma Michaux var. dichotoma - Poverty-grass. 2n = ?

Dry, sterile soil.

ARISTIDA LONGESPICA Poiret var. LONGESPICA - . 2n = ?

Open, dry or sterile soil, fields, peaty shores. From farther west and south.

Aristida longespica Poiret var. geniculata (Rafinesque) Fernald - . 2n = ?

Sandy soil, peaty shores, cranberry bogs.

Aristida oligantha Michaux - Prairie Three-awn. 2n = 22.

Dry, open, sterile soil.

Aristida purpurascens Poiret var. purpurascens - . 2n = ?

Dry sandy or gravelly soil.

ARISTIDA PURPUREA Nuttall var. NEALLEYI (Vasey) Allred - . 2n = 22, 44.

Dry soil, roadsides. From farther west. [A. GLAUCA (Nees) Walpers] Note: The sole New England voucher specimen from Chittenden Co., Vermont seen by us at the Pringle Herbarium of the University of Vermont has not been located at this herbarium by later workers or staff.

Aristida tuberculosa Nuttall - Sea-beach Needlegrass. 2n = ?

Dunes, dry sterile soil.

ARISTOLOCHIA (Family: Aristolochiaceae)

ARISTOLOCHIA CLEMATITIS Linnaeus - Birthwort. 2n = 14.

Waste places, roadsides, ballast. From Europe.

ARISTOLOCHIA MACROPHYLLA Lamarck - Dutchman's Pipe. 2n = 28.

Woodland borders. From farther south. [A. DURIOR - misapplied]

Aristolochia serpentaria Linnaeus - Virginia Snakeroot. 2n = 28.

Rich, often calcareous, woods.

ARISTOLOCHIA TOMENTOSA Sims - Pipevine. 2n = 28.

Thickets. From farther south and west.

ARMORACIA (Family: Brassicaceae)

ARMORACIA RUSTICANA P. Gaertner, B. Meyer & Scherbius - Horseradish. 2n = 32.

Moist soil of waste places, roadsides, fields. From Eurasia. [A. LAPATHIFOLIA Gilibert]

ARNICA (Family: Asteraceae)

Arnica lanceolata Nuttall subsp. lanceolata - 2n = (38), 76.

Damp banks and ledges in mountains, often subalpine. [A. mollis – misapplied; A. mollis var. petiolaris Fernald]

ARNOSERIS (Family: Asteraceae)

ARNOSERIS MINIMA (Linnaeus) Schweigger & Körte - Lamb’s Succory. 2n = 18.

Fields. From Europe.

ARONIA (Family: Rosaceae)

Aronia arbutifolia (Linnaeus) Persoon - Red Chokeberry. 2n = 34, 68.

Low woods, thickets, swamps, shores. [Photinia pyrifolia (Lamarck) K.R. Robinson & J.B. Phipps; Pyrus arbutifolia (Linnaeus) Linnaeus (son)]

Aronia melanocarpa (Michaux) Elliott - Black Chokeberry. 2n = 34.

Low woods, thickets, swamps, shores, sand dunes, dry, rocky slopes, bluffs, clearings, roadsides. [A. arbutifolia (Linnaeus) Persoon var. nigra (Willdenow) F. Seymour; Photinia melanocarpa (Michaux) K.R. Robinson & J.B. Phipps; Pyrus melanocarpa (Michaux) Willdenow]

Aronia hybrids

Aronia melanocarpa (Michaux) Elliott X A. X prunifolia (Marshall) Rehder (pro species) - .

Aronia X prunifolia (Marshall) Rehder (pro species) - Purple Chokeberry.

Swamps, shores, low thickets, clearings. [A. arbutifolia (Linnaeus) Persoon X A. melanocarpa (Michaux) Elliott; A. arbutifolia (Linnaeus) Persoon var. atropurpurea (Britton) F. Seymour; A. atropurpurea Britton; A. floribunda (Lindley) Sweet; Photinia floribunda (Lindley) K.R. Robinson & J.B. Phipps; Pyrus floribunda Lindley] Note: Some botanists consider this not to be a hybrid.

ARRHENATHERUM (Family: Poaceae)

ARRHENATHERUM ELATIUS (Linnaeus) P. Beauvois ex J. & C. Presl subsp. ELATIUS - Tall Oatgrass. 2n = (14), 28, (40), (42), (56).

Fields, roadsides, waste ground. From Europe.

ARRHENATHERUM ELATIUS (Linnaeus) P. Beauvois ex J. & C. Presl subsp. BULBOSUM (Willdenow) Schübler & G. Martens - . 2n = 28.

Fields, roadsides, waste ground. From Europe. [A. ELATIUS var. BULBOSUM (Willdenow) Spenner]

ARTEMISIA (Family: Asteraceae)

ARTEMISIA ABROTANUM Linnaeus - Southernwood. 2n = 18, (20), 36.

Waste places, roadsides. From Eurasia.

ARTEMISIA ABSINTHIUM Linnaeus - Common Wormwood. 2n = 18, (36).

Dry fields, roadsides, waste places. From Eurasia, northern Africa.

ARTEMISIA ANNUA Linnaeus - Sweet Annie. 2n = 18.

Waste places, roadsides, fields. From Eurasia.

ARTEMISIA BIENNIS Willdenow - 2n = 18.

Waste places, roadsides, clearings. From farther west.

Artemisia campestris Linnaeus subsp. canadensis (Michaux) Scoggan - Canada Wormwood. 2n = ?

Calcareous rocks and cliffs. [A. canadensis Michaux]

Artemisia campestris Linnaeus subsp. caudata (Michaux) H.M. Hall & Clements - 2n = 18.

Open, usually sandy, soil. [A. caudata Michaux]

ARTEMISIA CARRUTHII Alph. Wood ex Carruthers - 2n = 18.

Railroads. From farther west.

ARTEMISIA FILIFOLIA Torrey - Sand Sage. 2n = 18.

Waste places. From farther west.

ARTEMISIA FRIGIDA Willdenow - Prairie Sagewort. 2n = 18, 936), (90).

Waste places, roadsides, railroads, dry fields. From farther west.

ARTEMISIA LUDOVICIANA Nuttall subsp. LUDOVICIANA - Man Sage. 2n = (18), 36.

Roadsides, railroads, waste places. From farther west. [A. LUDOVICIANA var. AMERICANA (Besser) Fernald; A. LUDOVICIANA var. BRITTONII (Rydberg) Fernald; A. LUDOVICIANA var. GNAPHALOIDES (Nuttall) Torrey & A. Gray; A. LUDOVICIANA var. LATIFOLIA (Besser) Torrey & A. Gray; A. LUDOVICIANA var. PABULARIS (A. Nelson) Fernald; A. GNAPHALOIDES Nuttall]

ARTEMISIA PONTICA Linnaeus - Roman Wormwood. 2n = 18.

Roadsides, railroads, waste places, fields. From Eurasia.

ARTEMISIA STELLERIANA Besser - Dusty Miller. 2n = 18.

Sandy beaches, dunes. From northeastern Asia, Alaskan islands.

ARTEMISIA TRIDENTATA Nuttall subsp. TRIDENTATA - Big Sagebrush. 2n = 18, 36.

Fields. From farther west.

ARTEMISIA VULGARIS Linnaeus - Common Mugwort. 2n = 16, (18), (24), (34), (36), (40), (45), (54).

Roadsides, railroads, waste places, thickets. Eurasia, northern Africa. [A. VULGARIS var. GLABRA Ledebour; A. VULGARIS var. LATILOBA Ledebour]

ARTHRAXON (Family: Poaceae)

ARTHRAXON HISPIDUS (Thunberg) Makino subsp. HISPIDUS - . 2n = (10), (18), 36, (40).

Damp roadsides, ditches, shores. From eastern Asia. [A. HISPIDUS var. CRYPTATHERUS (Hackel) Honda]

ARUNCUS (Family: Rosaceae)

ARUNCUS DIOICUS (Walter) Fernald var. DIOICUS - Buck’s-beard. 2n = 18.

Waste places, roadsides, openings and borders of mixed woods. From farther west and south.

ASARUM (Family: Aristolochiaceae)

Asarum canadense Linnaeus - Wild Ginger. 2n = 26.

Rich woods and shaded, calcareous ledges. [A. canadense var. acuminatum Ashe; A. canadense var. reflexum (E.P. Bicknell) B.L. Robinson]

ASCLEPIAS (Family: Apocynaceae)

Asclepias amplexicaulis Smith - . 2n = ?

Dry, open, sandy soil in woods, thickets, fields, roadsides. [A. obtusifolia Michaux]

Asclepias exaltata Linnaeus - Poke Milkweed. 2n = 22.

Rich woods, woodland margins, clearings, thickets. [A. phytolaccoides G.F. Lyon ex Pursh]

Asclepias incarnata Linnaeus subsp. incarnata - Swamp Milkweed. 2n = 22.

Swamps, pond shores, wet thickets, meadows and fields.

Asclepias incarnata Linnaeus subsp. pulchra (Ehrhart ex Willdenow) Woodson - Hairy Milkweed. 2n = 22.

Swamps, pond shores, wet thickets, meadows and fields.

Asclepias purpurascens Linnaeus - Purple Milkweed. 2n = ?

Dry woods, woodland margins, thickets, openings, roadsides, dry fields.

Asclepias quadrifolia Jacquin - . 2n = ?

Rich, dry woods, often rocky and circumneutral or calcareous.

Asclepias syriaca Linnaeus - Common Milkweed. 2n = 22.

Roadsides, fields, meadows, thickets, railroad banks.

Asclepias tuberosa Linnaeus subsp. tuberosa - Butterfly-weed. 2n = 22.

Dry, open soil, roadsides, fields.

Asclepias variegata Linnaeus - White Milkweed. 2n = ?

Dry, wooded hillsides, thickets.

Asclepias verticillata Linnaeus - . 2n = 22.

Dry woods, open, often rocky, soil, fields, railroad banks.

Asclepias viridiflora Rafinesque - Green Milkweed. 2n = 22.

Sandy fields, openings, roadsides.

Asclepias hybrids

Asclepias amplexicaulis Smith X A. exaltata Linnaeus - .

Asclepias amplexicaulis Smith X A. syriaca Linnaeus - .

ASIMINA (Family: Annonaceae)

ASIMINA TRILOBA (Linnaeus) Dunal - Pawpaw. 2n = 16, 18, 27.

Roadsides, near buildings, disturbed paths. From farther south and west.

ASPARAGUS (Family: Asparagaceae)

ASPARAGUS OFFICINALIS Linnaeus - Asparagus. 2n = 20, (40), (80).

Roadsides, near buildings, fields, fence rows. From Europe.   NEBC herbarium image

ASPERUGO (Family: Boraginaceae)

ASPERUGO PROCUMBENS Linnaeus - Madwort. 2n = 48.

Waste places, streambanks. From Eurasia.

ASPERULA (Family: Rubiaceae)

ASPERULA ARVENSIS Linnaeus - Blue Woodruff. 2n = 22.

Waste places, roadsides, fields. From Eurasia. [GALIUM ARVENSE (Linnaeus) F. Hermann]

ASPLENIUM (Family: Aspleniaceae)

Asplenium montanum Willdenow - Mountain Spleenwort. 2n = 72.

Moist, sheltered crevices of chiefly non-calcareous cliffs and ledges.    NEBC herbarium image

Asplenium platyneuron (Linnaeus) Britton, Sterns & Poggenburg - Ebony Spleenwort. 2n = 72, (144).

Well-drained, rocky, circumneutral soils on slopes and ledges in deciduous forests (occasionally on crumbling mortar). [A. platyneuron var. incisum B.L. Robinson]    CONN herbarium image

Asplenium rhizophyllum Linnaeus - Walking Fern. 2n = 72.

Shaded, basic or circumneutral rocks, rarely on earth or at tree bases. [Camptosorus rhizophyllus (Linnaeus) Link]    CONN herbarium image

Asplenium ruta-muraria Linnaeus - Wall-rue. 2n = (72), 144.

Shaded crevices of calcareous cliffs and ledges. [A. cryptolepis Fernald; A. ruta-muraria var. cryptolepis (Fernald) Wherry]    CONN herbarium image

Asplenium trichomanes Linnaeus - Maidenhair Spleenwort. 2n = 72, (108), 144, (162), (216), (288).

Shaded crevices of mainly calcareous rocks (occasionally on crumbling mortar). [A. trichomanes subsp. quadrivalens D.E. Meyer]    CONN herbarium image

Asplenium viride Hudson - Green Spleenwort. 2n = 72.

Shaded, moist crevices and talus of calcareous and serpentine rocks and outcrops. [A. trichomanes-ramosum Linnaeus - invalid name]    CONN herbarium image

Asplenium hybrids

Asplenium X clermontiae Syme - .

[A. ruta-muraria Linnaeus X A. trichomanes Linnaeus]

Asplenium X ebenoides R.R. Scott (pro species) - Scott's Spleenwort - .

[A. platyneuron (Linnaeus) Britton, Sterns, & Poggenburg X A. rhizophyllum Linnaeus; X Asplenosorus ebenoides (R.R. Scott (pro species)) Wherry]

ASTER (Family: Asteraceae)

ASTER TATARICUS Linnaeus (son) - Shion. 2n = 54.

Roadsides, waste places. From northern Asia.

ASTILBE (Family: Saxifragaceae)

ASTILBE JAPONICA (C. Morren & Decaisne) A. Gray - False Spiraea. 2n = 14.

Waste places, roadsides. From Japan.

ASTRAGALUS (Family: Fabaceae)

Astragalus alpinus Linnaeus var. brunetianus Fernald - Northern Milk-vetch. 2n = ?

Calcareous river ledges and gravels.

Astragalus canadensis Linnaeus var. canadensis - . 2n = 16.

Shores.

ASTRAGALUS CONTORTUPLICATUS Linnaeus - Hungarian Milk-vetch. 2n = 16.

Wool waste. From Eurasia.

Astragalus eucosmus B.L. Robinson - . 2n = 32.

Calcareous, rocky or gravelly shores of streams.

ASTRAGALUS GLYCYPHYLLOS Linnaeus - Liquorice Milk-vetch. 2n = 16.

Roadsides, waste places. From Eurasia.

Astragalus robbinsii (Oakes) A. Gray var. robbinsii - 2n = ?

Dry, calcareous ledges above water. [considered to be extinct since 1894]

Astragalus robbinsii (Oakes) A. Gray var. jesupii Eggleston & E. Sheldon - 2n = ?

Rocky stream banks. [A. jesupii (Eggleston & E. Sheldon) Britton]

Astragalus robbinsii (Oakes) A. Gray var. minor (Hooker) Barneby - 2n = ?

Calcareous, ledges, cliffs and talus. [A. blakei Eggleston]

ATHYRIUM (Family: Athyriaceae)

Athyrium filix-femina (Linnaeus) Roth ex Mertens var. angustum (Willdenow) G. Lawson - Lady Fern. 2n = 80.

Moist woods, thickets, ravines, fields, meadows and swamps. [A. filix-femina var. michauxii (Sprengel) Farwell]    CONN herbarium image

Athyrium filix-femina (Linnaeus) Roth ex Mertens var. asplenioides (Michaux) Farwell - Southern Lady Fern. 2n = 80.

Moist woods, thickets, swamps, meadows.    CONN herbarium image

ATHYRIUM NIPONICUM (Mettenius) Hance - Japanese Painted Fern. 2n = 80.

Rock wall, crevices between paving stones. From east Asia.    CONN herbarium image

ATRIPLEX (Family: Amaranthaceae)

Atriplex dioica Rafinesque - Saline Saltbush. 2n = 36, 54.

Sea beaches. [A. subspicata (Nuttall) Rydberg]

ATRIPLEX GLABRIUSCULA Edmondston var. GLABRIUSCULA - Scotland Orach. 2n = 18.

Sea beaches, salt marshes, waste places. From north coastal Europe.

Atriplex glabriuscula Edmondston var. acadiensis (Taschereau) S.L. Welsh - Acadian Orach. 2n = 36.

Salt marshes with Spartina patens. [A. acadiensis Tascherau]

ATRIPLEX HORTENSIS Linnaeus - Garden Orach. 2n = 18.

Roadsides, disturbed soil. From Asia.

ATRIPLEX LITTORALIS Linnaeus - Grass-leaved Orach. 2n = 18.

Sea beaches, ballast dumps. From Europe. [A. PATULA Linnaeus subsp. LITTORALIS (Linnaeus) H.M. Hall & Clements]

Atriplex mucronata Rafinesque - Seabeach Orach. 2n = 18.

Sandy, sea beaches, salt marsh borders. [A. arenaria Nuttall; A. cristata Humboldt & Bonpland ex Willdenow var. arenaria (Nuttall) Kuntze]

Atriplex patula Linnaeus - Spearscale. 2n = (18), 36.

Sea beaches, roadsides, fields.

ATRIPLEX PROSTRATA Boucher ex de Candolle - Fat-hen. 2n = 18, (36).

Sea beaches, salt marshes. From Eurasia. [A. HASTATA misapplied; A. PATULA Linnaeus var. HASTATA misapplied]

ATRIPLEX ROSEA Linnaeus - Tumbling Orach. 2n = 18.

Salty flats, waste places, roadsides. From Eurasia.

ATRIPLEX SIBIRICA Linnaeus - Siberian Orach. 2n = 18.

Wool waste. From central and eastern Asia.

ATRIPLEX TATARICA Linnaeus - Tatarian Orach. 2n = 18, (36).

Waste places, ballast. From Eurasia.

AUREOLARIA (Family: Orobanchaceae)

Aureolaria flava (Linnaeus) Farwell - . 2n = 24.

Dry, open, usually oak or oak-pine woods, roadsides. [Gerardia flava Linnaeus]

Aureolaria pedicularia (Linnaeus) Rafinesque ex Pennell - . 2n = 28.

Dry, open deciduous woods and clearings, roadsides, usually in sandy soil, typically parasitizing species of Quercus. [A. pedicularia var. intercedens Pennell; Gerardia pedicularia Linnaeus var. pedicularia; G. pedicularia var. intercedens (Pennell) Fernald]

Aureolaria virginica (Linnaeus) Pennell - Downy False Foxglove. 2n = 26.

Dry, open woods, usually pine and oak. [Gerardia virginica (Linnaeus) Britton, Sterns & Poggenburg]

AURINIA (Family: Brassicaceae)

AURINIA SAXATILIS (Linnaeus) Desvaux - Basket-of-gold. 2n = 16.

Rock outcrops. From Eurasia. [ALYSSUM SAXATILE Linnaeus]

AVENA (Family: Poaceae)

AVENA FATUA Linnaeus subsp. FATUA - Wild Oat. 2n = (14), (28), 42.

Waste places. From Europe.

AVENA SATIVA Linnaeus - Oat. 2n = (20), 42, (48).

Waste places, roadsides. From Europe. [A. SATIVA var. ORIENTALIS (Schreber) Alefeld]

AVENA STRIGOSA Schreber - . 2n = 14, (28).

From Europe.

AVENELLA (Family: Poaceae)

Avenella flexuosa (Linnaeus) Drejer - Common Hairgrass. 2n = (14), (26), 28,(56).

Dry open soil, ledges. [Deschampsia flexuosa (Linnaeus) Trinius]

AVENULA (Family: Poaceae)

AVENULA PUBESCENS (Hudson) Dumort subsp. PUBESCENS - . 2n = 14 + (0-2)B, (16), (28).

Fields, roadsides. From Europe. [AVENA PUBESCENS Hudson; HELICTOTRICHON PUBESCENS (Hudson) Pilger]

AXYRIS (Family: Amaranthaceae)

AXYRIS AMARANTHOIDES Linnaeus - Russian Pigweed. 2n = 18.

Waste places, roadsides, fields. From Eurasia.

AZOLLA (Family: Salviniaceae)

AZOLLA CAROLINIANA Willdenow - Mosquito Fern n = 48; 2n = 44, 66.

Floating in quiet waters. From south of our range.   CONN herbarium image

Designed by Ray Angelo. Revised July 14, 2023