DIOSCOREACEAE, the Yam Family

Twining herbs with net-veined leaves and greenish or white flowers in panicles or racemes.

One species in Michigan; leaves ovate-cordate; flowers in summer Wild Yam, Dioscorea villosa.


AMARYLLIDACEAE, the Amaryllis Family

Plants with linear basal leaves, and perfect flowers, with 6-parted perianth, inferior ovary, and 6 stamens.

One species in Michigan; 1-2 dm. high; flowers yellow, 1 cm. wide, in spring Star Grass, Hypoxis hirsuta.


IRIDACEAE, the Iris Family

Herbs, with 6-parted perianth, inferior ovary, and 3 stamens.

1a. Flowers blue, 5 cm. wide or larger — 2.
1b. Flowers about 1 cm. wide (blue or white, from a spathe terminating a 2-edged stem 2-5 dm. high, spring and early summer) (Blue-eyed Grass) — 3.
2a. Flowering stems 4-8 dm. high (early summer) Blue Flag, Iris versicolor.
2b. Flowering stems 2 dm. or less high (spring) Dwarf Iris, Iris lacustris.
3a. Spathes terminal, sessile — 4.
3b. Spathes long-peduncled, axillary — 8.
4a. Spathe single — 5.
4b. Spathes 2 on each flowering stem — 7.
5a. Pedicels much longer than the inner (shorter) bract Blue-eyed Grass, Sisyrinchium mucronatum.
5b. Pedicels equaling or barely exceeding the inner bract — 6.
6a. Capsule brown; common species Blue-eyed Grass, Sisyrinchium angustifolium.
6b. Capsule green or yellowish; rare species Blue-eyed Grass, Sisyrinchium montanum.
7a. Leaves folded lengthwise; stems narrowly winged Blue-eyed Grass, Sisyrinchium hastile.
7b. Leaves flat; stem broadly winged, 2-3 mm. wide Blue-eyed Grass, Sisyrinchium albidum.
8a. Capsules pale straw-color or whitish — 9.
8b. Capsules brown, or tinged with purple — 10.
9a. Plant with straight fibrous bristles at base; pedicels long-exserted Blue-eyed Grass, Sisyrinchium farwellii.
9b. Plants not bristly at base; pedicels barely exserted Blue-eyed Grass, Sisyrinchium strictum.
10a. Pedicels scarcely exceeding the inner bract — 6a.
10b. Pedicels much exceeding the inner bract — 11.
11a. Stem 2-6 mm. wide; bracts 1.5-2 cm. long Blue-eyed Grass, Sisyrinchium gramineum.
11b. Stem 1-2 mm. wide; bracts 1-1.5 cm. long Blue-eyed Grass, Sisyrinchium apiculatum.


ORCHIDACEAE, the Orchis Family

Herbs, with irregular flowers, one petal, the lip, differing from the others in size and shape, inferior ovary, and one or two stamens adherent to the style.

1a. Flowers in a spike-like obviously twisted raceme; small, yellowish or greenish-white, in late summer and autumn (except 4a) (Ladies' Tresses) — 2.  
1b. Flowers solitary or in clusters, but never in a twisted raceme — 5.
2a. Flowers in 1 row Ladies' Tresses, Spiranthes gracilis.
2b. Flowers in several rows — 3.
3a. Lip constricted near the apex Ladies' Tresses, Spiranthes romanzoftiana.
3b. Lip not constricted — 4.
4a. Lip yellow; flowers in spring and early summer Ladies' Tresses, Spiranthes lucida.
4b. Lip white Ladies' Tresses, Spiranthes cernua.
5a. Brown, purple, or yellow plants, without green color, with scale-like leaves (1-4 dm. high; summer) (Coral Root) — 6.
5b. Plants with normal green color — 9.
6a. Lip white, not spotted Coral Root, Corallorrhiza trifida.
6b. Lip white, spotted with red — 7.
7a. Lip distinctly 3-lobed Coral Root, Corallorrhiza maculata.
7b. Lip entire, or barely toothed — 8.
8a. Flower, exclusive of ovary, 4 mm. long Coral Root, Corallorrhiza odontorhiza.
8b. Flower about 10 mm. long. Coral Root, Corallorrhiza striata.
9a. Leaf 1 or none at flowering time — 10.
9b. Leaves a single pair, basal, or opposite on the stem; never alternate on the stem — 19.
9c. Leaves several, all basal, prominently net-veined, and frequently blotched with white (scape 1-4 dm. high; flowers whitish, pubescent, in summer) (Rattlesnake Plantain) — 26.
9d. Leaves 2 or more, on the stem — 28.
10a. Foliage leaf absent or undeveloped at flowering time, or merely persisting through the winter from the previous year — 11.
10b. Foliage leaf present at flowering time — 12.
11a. Flower rose-purple, 3-5 cm. long, solitary or two (1-3 dm. high, early summer) Arethusa, Arethusa bulbosa.
11b. Flowers purplish-green, in racemes, with a spur 2 cm. long Crane-fly Orchis, Tipularia discolor.
11c. Flowers yellowish, purple tinged, in racemes; spur none (3-4 dm. high, early summer). Putty Root, Aplectrum hyemale.
12a. Leaf linear or linear-lanceolate — 13.
12b. Leaf of a broader shape — 14.
13a. Flower solitary or two; leaf just below the flower — 11a.
13b. Flowers in a loose raceme, sometimes only 2; leaf basal Calopogon, Calopogon pulchellus.
14a. Flowers greenish, yellowish, or white — 15.
14b. Flowers pink to purple, often variegated — 17.
15a. Flowers 6-10 mm. wide, with a spur about the same length (1-4 dm. high, summer) (Rein Orchis) — 35.  
15b. Flowers 5 mm. wide or less; spur none (1-2 dm. high; summer) (Adder's Mouth) — 16.
16a. Pedicels less than 5 mm. long; lip broadest below the middle Adder's Mouth, Microstylis monophyllos.
16b. Pedicels more than 5 mm. long; lip broadest near the apex Adder's Mouth, Microstylis unifolia.
17a. Flowers spicate; lip distinctly 3-lobed (1-2 dm. high; early summer) — 24.
17b. Flowers solitary or two — 18.
18a. Leaf on the stem, lanceolate to ovate — 34a.
18b. Leaf basal, round-ovate (2 dm. high or less; early summer) Calypso, Calypso bulbosa.
19a. Leaves opposite and sessile near the middle of the stem (1-3 dm. high; flowers in summer) (Tway-blade) — 20.
19b. Leaves basal — 21.
20a. Lip deeply 2-cleft (flowers purplish) Tway-blade, Listera cordata.
20b. Lip wedge-shape, with 2 round shallow lobes (flowers greenish-yellow) Tway-blade, Listera convallarioides.
21a. Lip an inflated sac about 4 cm. long — 29d.
21b. Lip not sac-like — 22.
22a. Flower with a spur 15-50 mm. long — 23.
22b. Flower not spurred (1-2 dm. high; early summer) (Tway-blade) — 25.
23a. Flowers purple or magenta, or with white markings — 24.
23b. Flowers greenish, yellowish, or white (1-4 dm. high; summer) (Rein Orchis) — 36.
24a. Leaf 1 (1-2 dm. high; early summer) Round-leaved Orchis, Orchis rotundifolia.
24b. Leaves 2 (-20 cm. high; late spring) Showy Orchis, Orchis spectabilis.
25a. Lip about 10 mm. long, purple Tway-blade, Liparis liliifolia.
25b. Lip about 5 mm. long, yellowish-green Tway-blade, Liparis loeselii.
26a. Perianth 8-10 mm. long; lip with elongated point Rattlesnake Plantain, Epipactis decipiens.
26b. Perianth 4-6 mm. long; lip sack-like — 27.
27a. Raceme loosely flowered, one-sided Rattlesnake Plantain, Epipactis repens var. ophioides.
27b. Raceme closely flowered, not one-sided Rattlesnake Plantain, Epipactis pubescens.
28a. Lip conspicuously sack-like, inflated (late spring and early summer) (Lady's Slipper) — 29.
28b. Lip not sack-like nor inflated — 32.
29a. Lip white (1-3 dm. high) White Lady's Slipper, Cypripedium candidum.
29b. Lip yellow (2-7 dm. high) — 30.
29c. Lip white, with crimson or purple markings — 31.
29d. Lip pink (1-4 dm. high, late spring) Stemless Lady's Slipper, Cypripedium acaule.
30a. Lip 2-3 cm. long. Small Yellow Lady's Slipper, Cypripedium parviflorum.
30b. Lip 3.5-5 cm. long Large Yellow Lady's Slipper, Cypripedium parviflorum var. pubescens.
31a. Lip 2 cm. long or less; sepals separate (1.5-3 dm. high) Ram's Head Lady's Slipper, Cypripedium arietinum.
31b. Lip 3 cm. long or more; the 2 lower sepals united Showy Lady's Slipper, Cypripedium hirsutum.
32a. Flowers solitary in the axils, or solitary and terminal; not spurred — 33.
32b. Flowers in terminal racemes, spurred — 38.
33a. Leaves a whorl of 5 (2-3 dm. high; petals greenish; late summer) Whorled Pogonia, Pogonia verticillata.
33b. Leaves alternate — 34.
34a. Leaves lanceolate or narrowly ovate, 2-8 cm. long, narrowed at base; flower terminal (1-4 dm. high; flowers pink purple, early summer) Snake Mouth, Pogonia ophioglossoides.
34b. Leaves ovate, 1-2 cm. long, clasping; flowers axillary (5-20 cm. high; flowers purple, summer) Nodding Pogonia, Pogonia trianthophora.
35a. Leaf basal; spur nearly straight Rein Orchis, Habenaria obtusata.
35b. Leaf on the stem; spur strongly curved Rein Orchis, Habenaria clavellata.
36a. Flower-stalk without bracts below the raceme; flowers yellowish-green Rein Orchis, Habenaria hookeri.
36b. Flower-stalk bearing bracts below the raceme; flowers greenish-white — 37.
37a. Spur 15-25 mm. long Rein Orchis, Habenaria orbiculata.
37b. Spur 30-50 mm. long Rein Orchis, Habenaria macrophylla.
38a. Lip fringed (Fringed Orchis) — 43.
38b. Lip not fringed (Rein Orchis) — 39.
39a. Lip with 2-3 evident teeth at apex — 40.
39b. Lip without apical teeth — 41.
40a. Stem-leaves 3 or more Rein Orchis, Habenaria bracteata.
40b. Stem-leaves 2 — 35b.
41a. Flowers white Rein Orchis, Habenaria dilatata.
41b. Flowers greenish-yellow — 42.
42a. Lip lanceolate, tapering toward the apex Rein Orchis, Habenaria hyperborea.
42b. Lip oblong, truncate at the apex Rein Orchis, Habenaria flava.
43a. Lip deeply 3-lobed, toothed or fringed — 44.  
43b. Lip not 3-lobed, but deeply fringed — 46.
44a. Flowers purple Purple Fringed Orchis, Habenaria psycodes.
44b. Flowers white or nearly so — 45.
45a. Spur 3 cm. long or more Prairie Fringed Orchis, Habenaria leucophaea.
45b. Spur 1-1.5 cm. long Ragged Fringed Orchis, Habenaria lacera.
46a. Flowers yellow Yellow Fringed Orchis, Habenaria ciliaris.
46b. Flowers white White Fringed Orchis, Habenaria blephariglottis.


PIPERACEAE, the Pepper Family

Herbaceous plants with alternate leaves, and flowers without either calyx or corolla.

One species in Michigan, a marsh plant with heart-shape leaves and slender racemes of white flowers Lizard's Tail, Saururus cernuus.


SALICACEAE, the Willow Family

Trees or shrubs, with dioecious flowers in catkins.

1a. Leaves less than twice as long as broad, on petioles 3 cm. long or more — 2.
1b. Leaves more than twice as long as broad, on petioles 2.5 cm. long or less. (The genus Salix, or Willow, contains about 30 species in Michigan, of which only the commoner are mentioned here. For the others the Manuals should be consulted.) — 8.
2a. Petioles strongly flattened laterally — 3.
2b. Petioles not flattened laterally — 6.
3a. Leaves broadly ovate or nearly circular — 4.
3b. Leaves broadly triangular or deltoid in shape — 5.
4a. Leaves coarsely toothed Large-toothed Aspen, Populus grandidentata.
4b. Leaves finely crenulate or serrate Quaking Aspen, Populus tremuloides.
5a. Tree with narrow spire-shape crown Lombardy Poplar, Populus nigra var. italica.
5b. Tree with spreading crown Cottonwood, Populus deltoides.
6a. Lower side of leaf densely tomentose White Poplar, Populus alba.
6b. Lower side of leaf glabrous or nearly so — 7.
7a. Petioles glabrous Balsam Poplar, Populus balsamifera.
7b. Petioles ciliate Balm of Gilead, Populus candicans.
8a. Trees — 9.
8b. Shrubs — 13.
9a. Petioles without glands — 10.  
9b. Petioles with glands — 11.
10a. Petiole short (about 5 mm.), broad and flat Black Willow, Salix nigra.
10b. Petiole slender, about 10-20 mm. long Peach-leaved Willow, Salix amygdaloides.
11a. Leaves green beneath Crack Willow, Salix fragilis.
11b. Leaves pale beneath — 12.
12a. Branches and twigs conspicuously drooping Weeping Willow, Salix babylonica.
12b. Branches and twigs not conspicuously drooping, yellow Yellow Willow, Salix alba var. vitellina.
13a. Shrubs of bogs — 14.
13b. Plants of sand-dunes along the Great Lakes — 15.
13c. Plants of dry upland hills — 16.
13d. Plants of wet ground, river-banks, and swamps — 17.
14a. Leaves densely white-tomentose beneath Willow, Salix candida.
14b. Leaves pale beneath but not tomentose Willow, Salix serissima.
14c. Leaves glabrous and green beneath Willow, Salix pedicellaris.
15a. Leaves linear Willow, Salix longifolia.
15b. Leaves ovate-lanceolate, tomentose beneath Willow, Salix syrticola.
15c. Leaves ovate-lanceolate, glabrous Willow, Salix glaucophylla.
16a. Leaves about 3 times as long as broad Willow, Salix rostrata.
16b. Leaves narrower, nearly sessile Willow, Salix tristis.
16c. Leaves narrower, distinctly petioled Willow, Salix humilis.
17a. Leaves linear or nearly so Willow, Salix longifolia.
17b. Leaves shining Willow, Salix lucida.
17c. Leaves silky Willow, Salix sericea.
17d. Leaves not as in the preceding 3 species — 18.
18a. Leaves rounded at base Willow, Salix cordata.
18b. Leaves acute at base — 19.
19a. Leaves finely serrulate Willow, Salix petiolaris.
19b. Leaves remotely serrate or nearly entire Willow, Salix discolor.


MYRICACEAE, the Sweet Gale Family

Shrubs, with monoecious or dioecious flowers in catkins, and aromatic foliage.

1a. Leaves pinnately lobed Sweet Fern, Myrica asplenifolia.
1b. Leaves merely serrate — 2.
2a. Shrub of sandy soil, shore of Lake Erie Bayberry, Myrica carolinensis.
2b. Shrub of bogs and shores, northern half of state Sweet Gale, Myrica gale.


JUGLANDACEAE, the Walnut Family

Trees with alternate pinnately compound leaves and flowers in catkins.

1a. Leaflets 11-23; pith divided by partitions into chambers — 2.
1b. Leaflets 5-11; pith not partitioned (Hickory) — 3.
2a. Pith brown; bark with flat longitudinal ridges Butternut, Juglans cinerea.
2b. Pith cream-color; bark of trunk without flat ridges Black Walnut, Juglans nigra.
3a. Bark of the trunk essentially smooth, not deeply furrowed or shaggy — 4.
3b. Bark of the trunk deeply furrowed or shaggy — 6.
4a. Leaflets glabrous beneath; buds greenish — 5.
4b. Leaflets somewhat pubescent beneath; buds bright yellow Bitter Nut, Carya cordiformis.
5a. Twigs hairy Small-fruited Hickory, Carya microcarpa.
5b. Twigs smooth Pignut Hickory, Carya glabra.
6a. Twigs and leaves both pubescent — 7.
6b. Twigs nearly smooth; leaves smooth beneath Shag-bark Hickory, Carya ovata.
7a. Twigs brownish; buds densely hairy Mocker-nut Hickory, Carya alba.
7b. Twigs orange; buds very slightly hairy King-nut Hickory, Carya laciniosa.


BETULACEAE, the Birch Family

Trees or shrubs with alternate simple leaves and inconspicuous monoecious flowers, the staminate flowers in catkins, and the pistillate in catkins or small clusters.

1a. Trees, with white or yellowish bark exfoliating in thin papery plates or scales — 2.
1b. Tree or shrub, with smooth, dark gray bark; trunk fluted with prominent longitudinal ridges Hornbeam, Carpinus caroliniana.
1c. Trees or shrubs; the bark more or less roughened, but not exfoliating; trunk not fluted — 3.
2a. Bark white or chalky Paper Birch, Betula alba var. papyrifera.
2b. Bark yellowish Yellow Birch, Betula lutea.
3a. Shrubs, with leaves 4 cm. long or less — 4.
3b. Shrubs or trees, with leaves 5 cm. long or more — 5.  
4a. Twigs glandular-warty Dwarf Birch, Betula glandulosa.
4b. Twigs not glandular Swamp Birch, Betula pumila.
5a. Twigs and bark with the odor of wintergreen Sweet Birch, Betula lenta.
5b. Twigs and bark without odor of wintergreen — 6.
6a. Fruit clusters woody, persistent on the plant for a long time — 7.
6b. Fruit clusters herbaceous, dropping in late autumn — 9.
7a. Leaves rusty or whitish beneath, and pubescent at least on the veins Speckled Alder, Alnus incana.
7b. Leaves green beneath, and either pubescent or smooth — 8.
8a. Leaves broadest at or below the middle Mountain Alder, Alnus crispa.
8b. Leaves broadest above the middle Smooth Alder, Alnus rugosa.
9a. Tree; fruit a cluster of bladder-like sacs each containing a small achene Ironwood, Ostrya virginiana.
9b. Shrubs; fruit a nut within a close-fitting involucre — 10.
10a. Involucre of 2 broad bracts, almost separate and not much longer than the fruit Hazel, Corylus americana.
10b. Involucre of united bracts, prolonged into a bristly beak beyond the fruit Beaked Hazel, Corylus rostrata.


FAGACEAE, the Beech Family

Trees (or 1 species shrubby), with alternate simple leaves and monoecious flowers, the staminate flowers in catkins, and the pistillate solitary or in small clusters. Fruit a nut (or acorn) enclosed in a cup or bur.

1a. Leaves serrate with numerous sharp-pointed teeth — 2.
1b. Leaves serrate, lobed, or entire, but never serrate with sharp-pointed teeth; fruit an acorn; pith 5-angled in the young twigs (Oak) — 3.
2a. Bark gray, smooth; buds 3-4 times longer than wide; nut Beech, Fagus grandifolia.
2b. Bark rough; buds relatively thicker; nut rounded Chestnut, Castanea dentata.
3a. Leaves entire, except for a bristle at the tip Shingle Oak, Quercus imbricaria.
3b. Leaves toothed or lobed, the points bristle-tipped — 4.
3c. Leaves toothed or lobed, the points without bristles — 10.
4a. Leaves entire below the middle, with a few shallow lobes beyond Black Jack Oak, Quercus marilandica.
4b. Leaves deeply lobed throughout — 5.
5a. Cup of the acorn saucer-shape, covering less than one-third of the acorn — 6.  
5b. Cup of the acorn hemispherical or top-shape, covering one-third or more of the acorn — 8.
6a. Length of the lateral leaf-lobes less than one-third the width of the leaf; acorn cup 2-2.5 cm. wide Red Oak, Quercus rubra.
6b. Length of the lateral leaf-lobes more than one-third the width of the leaf — 7.
7a. Acorn depressed-globose, about 1 cm. in diameter Pin Oak, Quercus palustris.
7b. Acorn ovoid, 1.5-2 cm. thick Schneck's Oak, Quercus schneckii.
8a. Leaves pubescent beneath Black Oak, Quercus velutina.
8b. Leaves glabrous beneath — 9.
9a. Buds glabrous; inner bark of the trunk yellow Hill's Oak, Quercus ellipsoidalis.
9b. Buds pubescent beyond the middle; inner bark of trunk red Scarlet Oak, Quercus coccinea.
10a. Leaves deeply pinnately lobed — 11.
10b. Leaves crenate, dentate, or sinuate, not lobed — 12.
11a. Leaf divided nearly to the middle by a pair of deep lateral lobes near the middle of the leaf; acorn more than half covered by the cup Bur Oak, Quercus macrocarpa.
11b. Leaf without a median pair of deeper lobes; acorn about one-fourth covered by the cup White Oak, Quercus alba.
12a. Leaves broadest at or near the middle, with numerous (8-13) sharp coarse teeth on each side Yellow Oak, Quercus muhlenbergii.
12b. Leaves broadest above the middle, with a few shallow, rounded or subacute teeth (7 or less on each side) — 13.
13a. Large tree; leaves densely white-tomentose beneath; acorn on a stalk 3-10 cm. long Swamp White Oak, Quercus bicolor.
13b. Shrub; leaves thinly white-tomentose beneath; acorn sessile or nearly so Scrub Oak, Quercus prinoides.


URTICACEAE, the Nettle Family

Herbs or trees, with small inconspicuous apetalous flowers.

1a. Trees or tall shrubs — 2.
1b. Herbs — 7.
2a. Leaves oblong-ovate to lanceolate, serrate — 3.
2b. Leaves broadly ovate to rotund, some of them lobed (Mulberry) — 6.
3a. Leaves thick, coarsely and doubly serrate, broadest near the middle (Elm) — 4.  
3b. Leaves thin, simply serrate, broadest distinctly below the middle Hackberry, Celtis occidentalis.
4a. Some of the branches with flat corky wings; leaves smooth above Cork Elm, Ulmus racemosa.
4b. Branches without corky wings; leaves more or less rough above — 5.
5a. Petioles and axillary buds glabrous White Elm, Ulmus americana.
5b. Petioles and axillary buds pubescent with rusty hairs Slippery Elm, Ulmus fulva.
6a. Leaves rough above Red Mulberry, Morus rubra.
6b. Leaves smooth above White Mulberry, Morus alba.
7a. Leaves alternate — 8.
7b. Leaves opposite — 9.
8a. Leaves 2-5 cm. long, stems pubescent Pellitory, Parietaria pennsylvanica.
8b. Leaves 8-20 cm. long; stem armed with stinging hairs Wood Nettle, Laportea canadensis.
9a. Twining plant; leaves serrate or cleft Hop, Humulus lupulus.
9b. Erect plant; leaves palmately compound Hemp, Cannabis sativa.
9c. Erect plants; leaves not lobed or compound — 10.
10a. Stems armed with stinging hairs — 11.
10b. Stems glabrous or rough, but not with stinging hairs — 12.
11a. Leaves ovate, with a heart-shape base Stinging Nettle, Urtica dioica.
11b. Leaves lanceolate or ovate-lanceolate, not heart-shape at base Slender Nettle, Urtica gracilis.
12a. Stems glabrous, pellucid Clearweed, Pilea pumila.
12b. Stems rough, opaque False Nettle, Boehmeria cylindrica.