Chapter I: Part 1

THE PLANTS OF MICHIGAN

SIMPLE KEYS FOR THE IDENTIFICATION OF THE NATIVE SEED PLANTS OF THE STATE

By HENRY ALLAN GLEASON, Ph. D. Associate Professor of Botany and Director of the Botanical Gardens and Arboretum in the University of Michigan

1918

COPYRIGHT, 1918 GEORGE WAHR

PUBLISHED BY GEORGE WAHR ANN ARBOR

PRINTED BY THE ANN ARBOR PRESS

PREFACE

This book is not intended for the expert botanist. He should consult one of the regular Manuals which give full descriptions of each species of plant.

Neither is it intended for the merely curious. Only those who have sufficient interest in a plant to observe it can find its name by this book.

Furthermore, it is not a textbook. It does not attempt to convey botanical information, but offers merely an opportunity to learn the names of plants.

Its mission is fully accomplished if, through its use, students, vacationists, and plant-lovers in general are able to recognize by name the plants about them.

HOW TO USE THE BOOK

One recognizes a plant by the presence of structural features peculiar to itself, and not found on any other kind of plant. In such a book as this, these characters are given one or a few at a time, and contrasted with the characters which other sorts of plants possess. Such a presentation is called a Key, and by its proper use the name may be learned of any plant considered in it. This process is called Identification.

Keys are constructed in several different ways, although the principle of all is the same. In this book, the user will begin with lines 1a and 1b on the page headed Key to the Groups. Each of these lines includes some descriptive matter, but only one of them can apply to the plant being identified. For example, if the plant to be identified is an Oak, line 1a will apply perfectly, and the same line will also apply to any other kind of tree or to any shrub. But if the plant is a Violet, a Buttercup, or any other herb, line 1b agrees and line 1a will not apply. At the end of each line is a reference to be consulted next. If the plant is a tree or shrub, one turns accordingly to Group 1, on page ix, and begins again at the first number given. If the plant is an herb, he follows the reference to line 2, just below, and again compares the plants with lines 2a and 2b.

Under every number at least two lines of description are given, designated a and b, and under a few numbers additional lines appear, designated c, d, etc. In every case, the user of the key will select from the different lines under the same number that particular line which agrees with the structure of the plant, and follow up the reference given at the end of that line. Eventually one finds at the end of a line, instead of a number, the name of a family of plants, to which this particular plant belongs, and then turns over to the page where this family is treated. Under each family is a similar key, to be followed in exactly the same way, until finally one finds instead of a number the common name and the scientific name of the plant in hand. The process of identification is now completed, and the student has found the name of the plant.

In some cases, a reference is made in the key to a particular portion of the family key. One then turns directly to this particular number in the family key, and continues his identification in the usual way.

As a definite example of the use of the key, suppose that one has in hand a branch of the White Oak, and that he does not know its name. To determine its name, he will trace it through the following steps in the key. Under the Key to the Groups, it agrees with line 1a, which refers to Group 1, Woody Plants. Under this group it agrees in structure with line 1a, which refers to 2; with line 2b, referring to 21; with line 21b, referring to 22; with 22b, referring to 29; with 29b, referring to 32; with 32c, referring to 47; with 47b, referring to 48; with 48b, referring to 51; with 51b, referring to number 1b in the Beech Family. Turning to the proper number in this family, the plant is referred to line 3; it agrees with line 3c, referring to 10; with 10a, referring to 11; and with 11b, which gives the name of the plant. White Oak, _Quercus alba_.

As a second example, suppose one has a common yellow-flowered plant blooming on lawns and roadsides in spring. Under the Key to the Groups, it agrees with 1b, referring to 2; with 2b, referring to 3; and its net-veined leaves place it in 3b, referring to Group 4, Dicotyledones. Under this group, its basal leaves place it in 1b, referring to 2; its simple leaves in 2b, referring to 18; the absence of stem-leaves places it in 18b, referring to 23; its solitary flowers on each flower-stalk place it in 23b, referring to 24; its yellow flowers agree with 24a, referring to 25; and its milky juice refers the plant to number 16, in the Composite Family. In the key to this family, its lobed leaves agree with 16b, referring on to 17; its large flowers with 17b, giving one the common name Dandelion, and referring on to 18 to determine which kind of Dandelion the plant may be.

At some point in the key there will be found for each plant a statement in parentheses. This is general information concerning the height of the plant, the color of the flowers, or the season of bloom. It must be remembered that the height of plants is subject to great variation; that most plants have white-flowered varieties; and that the month of bloom depends largely on the latitude and the climate. Therefore this general information should not be used as means of distinguishing species.

=The names of plants.= Each plant bears a scientific name. This is composed of two parts and is usually of Latin or Greek derivation. In some cases these names are taken directly from the Latin language, as _Quercus_, the Oak, or _Acer_, the Maple. In other cases the name may indicate some characteristic feature of the plant, as _Polygonum_, many joints, for the Knotweed, or _Ammophila_, sand-loving, for the Beach Grass.

An English name is also given for almost every kind of plant. In a few cases there is no accepted English name, and none has been given. In many cases the same English name applies to several kinds of plants and has been repeated for each. When this is so, the common name is given in the key in parentheses before the scientific name is reached. Thus, if one is satisfied to know merely that his plant is a dandelion, he learns it in line 17b of the key to the Composite Family, but to discover which kind of a dandelion he has, he must follow through the key and use the scientific name.

There is in this book, therefore, no necessity of learning or using scientific names. The less critical may be satisfied with an English name, and others may use the scientific names as they see fit.

=Possible Errors.= In using this book, care must be taken to compare all the lines under each number with the plant, and to use judgment in selecting the right one. While faulty observation or poor judgment may lead to error, a mistake is usually due to carelessness in not following correctly the reference at the end of the line chosen. If one reaches a number in which none of the lines of description agrees with the plant, it is very probable that he has made a mistake at an earlier stage of the identification, and he should then begin anew.

It has been the intention of the author to make the key as nearly as possible proof against errors of judgment. For example, the Indian Turnip may be sought under either Group 3 or Group 4; the Matrimony Vine may be identified either as a shrub or as an herb, and numerous other similar examples may be discovered.

=Botanical Information Needed.= It is presumed that those using the book will be familiar with the parts of the flower and with the commoner descriptive terms applied to leaves. Unusual terms have been avoided as far as possible, but those which do occur, as well as the simpler ones, are explained in the glossary.

In general, only those characters have been used in the keys which can be observed without a magnifying glass and without dissection of the flower.

In several groups of plants, reference is made to the fuller descriptions to be found in the Manuals. The standard manuals for Michigan are Gray's New Manual of Botany, 7th edition (American Book Company, $2.50), and Britton and Brown, Illustrated Flora of the Northern States and Canada (Chas. Scribner's Sons, $13.50). These books may be consulted in most school or public libraries.

All dimensions are expressed in the metric system. For convenience, it may be stated that 25 millimeters (mm.) are about equal to one inch; 1 centimeter (cm.) to two-fifths of an inch; 1 decimeter (dm.) to 4 inches; and 1 meter (m.) is a little more than 3 feet.

KEY TO GROUPS

1a. Trees, shrubs, or woody climbers, with stems which last from year to
year Group 1, =WOODY PLANTS=, p. ix.

1b. Herbaceous plants, with stems which live above ground only a single
season --2.

2a. Plants with unusual habits or structures, including leafless,
colorless, submerged, floating, parasitic, or hollow-leaved
plants Group 2, =UNUSUAL PLANTS=, p. xxiii.

2b. Ordinary terrestrial or swamp plants, without unusual
structural peculiarities --3.

3a. Leaves parallel-veined (or net-veined in a few species); parts of
the flower usually in threes or sixes, never in fives; wood-fibers
scattered through the stem; seed with one cotyledon. All plants with
definitely parallel-veined leaves may be identified through this
division, unless the parts of the flower are distinctly in fives.
Group 3, =MONOCOTYLEDONES=, p. xxvii.

3b. Leaves net-veined (or parallel-veined in a few species); parts of
the flower usually in fours or fives; wood-fibers arranged in a
circle in the stem; seeds with two cotyledons. All plants with
definitely net-veined leaves may be identified through this
division. Group 4, =DICOTYLEDONES=, p. xxx.

Note:--In order to avoid possible chances of error, many plants have been treated under both of the above groups. The following hints may also be useful in distinguishing Groups 3 and 4:

All herbaceous plants with deeply lobed, dissected or compound leaves may be sought under the Dicotyledones.

All herbaceous plants with five stamens in each flower, or with seven or more stamens and one ovary in each flower, may be sought under Dicotyledones.

GROUP 1, WOODY PLANTS

1a. Trees, with erect stem and central trunk, attaining a height of 6 m.
(20 ft.) or more --2.

1b. Shrubs or woody vines, without true tree habit, or attaining heights
of less than 6 m. (20 ft.) --52.

2a. Key for use in earliest spring, for trees which have flowers
but no leaves --3.

2b. Key for use with trees bearing leaves --21.

3a. Flowers in catkins, without brightly colored or petal-like parts
--4.

3b. Flowers not in catkins, either with or without petals --14.

4a. Leaf-scars and lateral buds 2-ranked, i. e., in two
longitudinal rows with the third leaf above the first --5.

4b. Leaf-scars and buds in three or more longitudinal rows --9.

5a. From 1 to 3 bud-scales visible on each leaf-bud
2b, in =FAGACEAE=, p. 22.

5b. From 4 to 7 bud-scales visible on each leaf-bud --6.

5c. From 8 to 20 bud-scales visible on each leaf-bud; buds long and
slender; bark of the trunk smooth --8.

6a. Bundle-scars 5 or more 2b, in =URTICACEAE=, p. 23.

6b. Bundle-scars 3 --7.

7a. Twigs bearing numerous dwarf branches thickly covered with crowded leaf-scars (Birch) =BETULACEAE=, p. 21.

7b. Twigs without dwarf branches (Ironwood) 9a, in =BETULACEAE=, p. 22.

8a. Trunk cylindrical or nearly so 2a, in =FAGACEAE=, p. 22.

8b. Trunk prominently fluted with longitudinal ridges
1b, in =BETULACEAE=, p. 21.

9a. Bundle-scars 3 in each leaf-scar --10.

9b. Bundle scars more than 3 in each leaf-scar --12.

10a. Pith divided into separate cavities by transverse partitions
1a, in =JUGLANDACEAE=, p. 21.

10b. Pith not partitioned --11.

11a. Buds small, with only one external bud-scale
1b, in =SALICACEAE=, p. 19.

11b. Buds with more than one outer bud-scale
1a, in =SALICACEAE=, p. 19.

12a. Buds clustered near the tips of the twigs
1b, in =FAGACEAE=, p. 22.

12b. Buds not clustered at the tips of the twigs --13.

13a. Buds with about 3 visible bud-scales 2b, in =FAGACEAE=, p. 22.

13b. Terminal bud large, with 4 or more visible bud-scales
1b, in =JUGLANDACEAE=, p. 21.

14a. Flowers conspicuous, brightly colored, at least 8 mm. wide.
with both calyx and corolla --15.

14b. Flowers inconspicuous, seldom brightly colored, and then less
than 8 mm. wide --17.

15a. Flowers irregular, pink or red 3a, in =LEGUMINOSAE=, p. 58.

15b. Flowers regular, white --16.

16a. Ovary one, superior, in the center of the flower
32b, in =ROSACEAE=, p. 54.

16b. Ovary inferior, appearing as a swelling below the calyx at the
summit of the pedicel 42b, in =ROSACEAE=, p. 55.

17a. Leaf-scars and buds opposite --18.

17b. Leaf-scars and buds alternate --19.

18a. Bundle-scar one in each leaf-scar 1b, in =OLEACAE=, p. 88.

18b. Bundle-scars 3 or more in each leaf-scar =ACERACEAE=, p. 70.

19a. Bundle-scar 1 in each leaf-scar 1b, in =LAURACEAE=, p. 41.

19b. Bundle-scars 3 in each leaf-scar --20.

19c. Bundle-scars 5 in each leaf-scar 7a, in =LEGUMINOSAE=, p. 58.

20a. Branches thorny 5a, in =LEGUMINOSAE=, p. 58.

20b. Branches not thorny 3a, in =URTICACEAE=, p. 24.

--21--

21a. Leaves narrow, needle-like or scale-like; trees mostly evergreen
=PINACEAE=, p. 1.

21b. Leaves broader, flat, never needle-like or scale-like, falling in
winter --22.

22a. Leaves compound --23.

22b. Leaves simple --29.

23a. Leaves opposite --24.

23b. Leaves alternate --26.

24a. Leaves palmately compound with 5-7 leaflets
=SAPINDACEAE=, p. 70.

24b. Leaves pinnately compound --25.

25a. Leaflets 3-5 1a, in =ACERACEAE=, p. 70.

25b. Leaflets 7-11 1b, in =OLEACEAE=, p. 88.

26a. Stem or branches thorny 4a, in =LEGUMINOSAE=, p. 58.

26b. Stem or branches not thorny --27.

27a. Leaflets entire 7a, in =LEGUMINOSAE=, p. 58.

27b. Leaflets entire except for a few large glandular teeth near their
base =SIMARUBACEAE=, p. 65.

27c. Leaflets serrate their entire length --28.

28a. Upper leaflets less than 25 mm. wide
4b, in =ROSACEAE=, p. 51.

28b. Upper leaflets more than 25 mm. wide
=JUGLANDACEAE=, p. 21.

29a. Leaves opposite --30.

29b. Leaves alternate --32.

30a. Leaves entire =CORNACEAE=, p. 83.

30b. Leaves toothed or lobed, not entire --31.

31a. Leaves lobed 1b, in =ACERACEAE=, p. 70.

31b. Leaves merely toothed 27b, in =CAPRIFOLIACEAE=, p. 111.

32a. Leaves entire --33.

32b. Leaves toothed --36.

32c. Leaves lobed --47.

33a. Leaves heart-shape 3a, in =LEGUMINOSAE=, p. 58.

33b. Leaves not heart-shape --34.

34a. Twigs and foliage spicy-aromatic 1b, in =LAURACEAE=, p. 41.

34b. Twigs and foliage not aromatic --35.

35a. Pith 5-angled; fruit an acorn 3a, in =FAGACEAE=, p. 22.

35b. Pith not 5-angled; fruit a berry 1a, in =CORNACEAE=, p. 83.

36a. Leaves oblique at base, i. e., one side of the leaf larger
than the other --37.

36b. Leaves symmetrical, not oblique at base --38.

37a. Leaves heart-shape, about as broad as long =TILIACEAE=, p. 72.

37b. Leaves oval or ovate, much longer than wide
1a, in =URTICACEAE=, p. 23.

38a. Stems thorny 41b, in =ROSACEAE=, p. 54.

38b. Stems not thorny --39.

39a. Leaves finely toothed, with 3-many teeth per centimeter of margin
--40.

39b. Leaves coarsely toothed, with 1-2 teeth per centimeter of margin
--46.

40a. Petioles laterally compressed 2a, in =SALICACEAE=, p. 19.

40b. Petioles not compressed --41.

41a. Leaves, or many of them, crowded on short spur-like branches --42.

41b. Leaves scattered, not on short spur-like branches --43.

42a. Bark of the trunks separating in thin papery or leathery
sheets =BETULACEAE=, p. 21.

42b. Bark of the trunk not papery or leathery
24b, in =ROSACEAE=, p. 53.

43a. Lateral leaf-veins straight and parallel, and terminating in the
teeth =BETULACEAE=, p. 21.

43b. Lateral veins more or less curved, and not ending in the teeth
--44.

44a. Leaves palmately veined, about as broad as long; juice
somewhat milky 2b, in =URTICACEAE=, p. 23.

44b. Leaves pinnately veined; juice not milky --45.

45a. Willows, with slender leaves and brittle twigs
8a, in =SALICACEAE=, p. 19.

45b. Trees with lanceolate, ovate, or oblong leaves and tough twigs
30, in =ROSACEAE=, p. 54.

45c. Cottonwoods, with broad, heart-shape or rounded leaves
1a, in =SALICACEAE=, p. 19.

46a. Petioles laterally compressed 2a, in =SALICACEAE=, p. 19.

46b. Petioles not compressed; lateral veins straight and parallel,
running directly to the teeth =FAGACEAE=, p. 22.

47a. Stem thorny 41b, in =ROSACEAE=, p. 54.

47b. Stem not thorny --48.

48a. Leaves palmately veined --49.

48b. Leaves pinnately veined --51.

49a. Lobes of the leaf entire 1b, in =LAURACEAE=, p. 41.

49b. Lobes of the leaf serrate --50.

50a. Juice somewhat milky; lateral buds visible
2b, in =URTICACEAE=, p. 23.

50b. Juice not milky; lateral buds covered by the base of the
petiole =PLATANACEAE=, p. 51.

51a. Leaves with 4 large entire lobes; stem marked with a ring at each
node =MAGNOLIACEAE=, p. 40.

51b. Leaves with many lobes; stem not ringed 1b, in =FAGACEAE=, p. 22.

--52--

52a. For specimens bearing leaves only --53.

52b. For specimens bearing flowers only --140.

52c. For specimens with both leaves and flowers --155.

53a. Leaves narrow, needle-like or scale-like, mostly evergreen --54.

53b. Leaves broader, flat or rolled, but not needle-like or scale-like
--56.

54a. Foliage densely gray-pubescent; low bushy shrubs with yellow
flowers 2a, in =CISTACEAE=, p. 74.

54b. Foliage green --55.

55a. Leaves opposite or whorled =PINACEAE=, p. 1.

55b. Leaves scattered on the stem =TAXACEAE=, p. 2.

56a. Twining or climbing vines --57.

56b. Not climbing or twining --66.

57a. Thorny vines --58.

57b. Not thorny --60.

58a. Climbing by tendrils at the base of the leaves
4b, in =LILIACEAE=, p. 11.

58b. Tendrils none --59.

59a. Leaves simple 5a, in =SOLANACEAE=, p. 100.

59b. Leaves compound 8a, in =ROSACEAE=, p. 52.

60a. Leaves compound --61.

60b. Leaves simple --63.

61a. Leaves with 5 leaflets 1a, in =VITACEAE=, p. 71.

61b. Leaves with 3 leaflets --62.

62a. Plant climbing by tendril-like leaf-stalks
1a, in =RANUNCULACEAE=, p. 35.

62b. Plant climbing by hold-fast roots
5b, in =ANACARDIACEAE=, p. 69.

63a. Leaves opposite 5a, in =CAPRIFOLIACEAE=, p. 110.

63b. Leaves alternate --64.

64a. Plants climbing by tendrils 1b, in =VITACEAE=, p. 71.

64b. Twining plants --65.

65a. Leaves ovate-oblong, attached by the base
1a, in =CELASTRACEAE=, p. 69.

65b. Leaves almost round, peltate near the edge =MENISPERMACEAE= p. 40.

66a. Leaves opposite --67.

66b. Leaves alternate --84.

67a. Leaves compound --68.

67b. Leaves simple --69.

68a. Leaflets 3 =STAPHYLEACEAE=, p. 69.

68b. Leaflets 7 or more 1a, in =CAPRIFOLIACEAE=, p. 109.

69a. Leaves palmately veined, or at least with a pair of prominent
lateral veins from the base --70.

69b. Leaves pinnately veined --72.

70a. Leaves not lobed 1b, in =RHAMNACEAE=, p. 71.

70b. Leaves more or less lobed --71.

71a. Leaves with stipules 22a, in =CAPRIFOLIACEAE=, p. 111.

71b. Leaves without stipules 2a, in =ACERACEAE=, p. 70.

72a. Leaves serrate --73.

72b. Leaves entire --77.

73a. Stem thorny 1b, in =RHAMNACEAE=, p. 71.

73b. Stem not thorny --74.

74a. Bark of the ripe twigs green 1b, in =CELASTRACEAE=, p. 69.

74b. Bark of the ripe twigs brown, reddish, or gray --75.

75a. Twigs with a prominent hairy ridge extending downward from the
middle of the line connecting the petiole bases
13a, in =CAPRIFOLIACEAE=, p. 110.

75b. Twigs without any pubescent ridge --76.

76a. Erect shrubs; leaves obviously toothed
11b, in =CAPRIFOLIACEAE=, p. 110.

76b. Spreading shrubs; most of the leaves entire, and only here and
there some with serrate margins
18b, in =CAPRIFOLIACEAE=, p. 110.

77a. Leaves silvery beneath with a dense coating of scales
=ELAEAGNACEAE=, p. 77.

77b. Leaves green beneath, or somewhat hairy and light-colored --78.

78a. Aquatic plant with lanceolate leaves, and stems bending over
and into the water 1a, in =LYTHRACEAE=, p. 77.

78b. Not truly aquatic, although frequently in wet places --79.

79a. Leaves evergreen, as shown by their presence on the older stems
18a, in =ERICACEAE=, p. 85.

79b. Leaves deciduous each year --80.

80a. Leaves dotted with translucent dots, easily seen when the leaf
is held to the light 1a, in =HYPERICACEAE=, p. 73.

80b. Leaves not dotted with translucent dots --81.

81a. Lateral veins curved forward and running almost parallel to the
leaf-margin =CORNACEAE=, p. 83.

81b. Lateral veins spreading, and not paralleling the leaf-margin --82.

82a. Leaves with stipules 1a, 1a, in =RUBIACEAE=, p. 108.

82b. Leaves with a prominent ridge connecting them at the base
--83.

82c. Leaves with neither stipules nor connecting ridges
1a, in =OLEACEAE=, p. 88.

83a. Bundle-scar one in each leaf-scar 18b, in =CAPRIFOLIACEAE=, p. 110.

83b. Bundle-scars three in each leaf-scar (Honeysuckle)
12, in =CAPRIFOLIACEAE=, p. 110.

84a. Leaves compound --85.

84b. Leaves simple --95.

85a. Stems prickly or thorny --86.

85b. Stems without prickles or thorns --88.

86a. Leaves twice-pinnate 4a, 1a, in =ARALIACEAE=, p. 80.

86b. Leaves evenly pinnate 5b, in =LEGUMINOSAE=, p. 58.

86c. Leaves odd-pinnate or trifoliate --87.

87a. Leaflets entire 1a, 1a, in =RUTACEAE=, p. 65.

87b. Leaflets serrate 3b, 3b, in =ROSACEAE=, p. 51.

88a. Leaflets 3 --89.

88b. Leaflets 5 to many --91.

89a. Tall shrubs; leaflets entire or minutely toothed
1b, in =RUTACEAE=, p. 65.

89b. Shrubs 2 m. high or less; leaves conspicuously toothed --90.

90a. Stipules present 17b, in =ROSACEAE=, p. 53.

90b. Stipules none 1b, in =ANACARDIACEAE=, p. 68.

91a. Leaflets 6-25 mm. long --92.

91b. Leaflets 30 mm. long, or more --93.

92a. Leaflets mostly 5, rarely 3 or 7 7a, in =ROSACEAE=, p. 52.

92b. Leaflets mostly 9-19, 15 mm. long or more
26a, in =LEGUMINOSAE=, p. 60.

92c. Leaflets mostly 25-45, less than 15 mm. long
8a, in =LEGUMINOSAE=, p. 58.

93a. Leaflets entire 3a, in =ANACARDIACEAE=, p. 68.

93b. Leaflets entire, except for 1-4 large glandular teeth near their
base =SIMARUBACEAE=, p. 65.

93c. Leaflets toothed throughout --94.

94a. Juice milky 1a, in =ANACARDIACEAE=, p. 68.

94b. Juice not milky 3a, in =ROSACEAE=, p. 51.

95a. Leaves minute, scale-like, appressed 2a, in =CISTACEAE=, p. 74.

95b. Leaves 3-10 mm. long, spreading, completely rolled into a tube
=EMPETRACEAE=, p. 68.

95c. Leaves normal in shape, green in color --96.

96a. Leaves evergreen, as shown by their presence on the older
parts of the stem 4b, in =ERICACEAE=, p. 84.

96b. Leaves deciduous --97.

97a. Stems or branches thorny --98.

97b. Stems or branches without thorns or thorny leaves --103.

98a. Leaves conspicuously palmately veined --99.

98b. Leaves pinnately veined, or sometimes with smaller lateral
veins arising from the end of the petiole --100.

99a. Leaves 5 cm. wide or less 1a, in =SAXIFRAGACEAE=, p. 49.

99b. Leaves 15 cm. wide or more 1a, in =ARALIACEAE=, p. 80.

100a. Leaves entire 5a, in =SOLANACEAE=, p. 100.

100b. Leaves toothed or somewhat lobed --101.

101a. Leaves with bristly margins; some of the thorns three-pointed
2a, in =BERBERIDACEAE=, p. 40.

101b. Leaves not bristly on the margin; thorns not branched --102.

102a. Only lateral thorns present 41b, in =ROSACEAE=, p. 54.

102b. Only terminal thorns present 2a, in =RHAMNACEAE=, p. 71.

103a. Leaves palmately veined, or with one or more pairs of lateral
veins from the base of the leaf --104.

103b. Leaves pinnately veined --111.

104a. Leaves entire --105.

104b. Leaves toothed --106.

104c. Leaves palmately lobed --108.

105a. Foliage fragrant when crushed; leaves ovate
1b, in =LAURACEAE=, p. 41.

105b. Foliage not aromatic; leaves heart-shape
3b, in =LEGUMINOSAE=, p. 58.

106a. Lateral veins straight and parallel, running to the teeth of
the leaf 3a, in =BETULACEAE=, p. 22.

106b. Lateral veins curved or branched, and not running straight to
the teeth --107.

107a. Tall shrubs with somewhat milky juice and broadly ovate leaves
2b, in =URTICACEAE=, p. 23.

107b. Low shrubs less than 1 m. high with watery juice
1b, in =RHAMNACEAE=, p. 71.

108a. Leaves with 2 or 3 entire lobes, spicy-fragrant when crushed
1b, in =LAURACEAE=, p. 41.

108b. Leaves with milky juice 2b, in =URTICACEAE=, p. 23.

108c. Leaves neither spicy-fragrant nor with milky juice --109.

109a. Stem covered with brown bristles 29, in =ROSACEAE=, p. 54.

109b. Stem not bristly --110.

110a. Sides of the petiole strongly decurrent on the stem;
bundle-scars crowded or nearly in contact in the leaf-scars
28b, in =ROSACEAE=, p. 53.

110b. Sides of petiole little decurrent or not at all; bundle-scars
distinctly separate 2b, in =SAXIFRAGACEAE=, p. 49.

111a. Leaves aromatically fragrant when crushed --112.

111b. Leaves not aromatically fragrant when crushed --113.

112a. Leaves broadly obovate, entire; a common woodland shrub
1a, in =LAURACEAE=, p. 41.

112b. Leaves linear-lanceolate or oblanceolate, conspicuously
toothed or entire =MYRICACEAE=, p. 20.

113a. Leaves entire --114.

113b. Leaves toothed or lobed --121.

114a. Base of the petiole covering the axillary buds; twigs marked
with rings =THYMELAEACEAE=, p. 77.

114b. Base of petiole not covering the bud, and twigs not marked
with rings --115.

115a. Pith with prominent partitions; tall shrubs with fetid bark;
leaves obovate, 10 cm. long or larger =ANONACEAE=, p. 40.

115b. Pith not partitioned; leaves smaller --116.

116a. Leaves waxy or resinous underneath
24b, in =ERICACEAE=, p. 86.

116b. Leaves not waxy or resinous --117.

117a. Lateral veins curved forward and almost parallel to the margin of
the leaf 2a, in =CORNACEAE=, p. 83.

117b. Lateral veins spreading --118.

118a. Leaves lanceolate or linear, much longer than wide --119.

118b. Leaves ovate or elliptical --120.

119a. Stem weak, spreading or trailing 5a, in =SOLANACEAE=, p. 100.

119b. Stems, or some of them, erect 3b, in =LEGUMINOSAE=, p. 58.

120a. Leaves with purple petioles, which are at least one-fourth as
long as the leaf-blade 1a, in =AQUIFOLIACEAE=, p. 69.

120b. Leaves with short petioles or sessile
24c, in =ERICACEAE=, p. 86.

121a. Lateral veins straight and parallel, mostly ending in the teeth of
the leaf --122.

121b. Lateral veins not straight and parallel --129.

122a. Leaves 2-ranked, i. e., in two longitudinal rows, with the
third leaf directly above the first --123.

122b. Leaves not 2-ranked --127.

123a. Leaves unsymmetrical, oblique at the base, i. e., with one side of
the leaf larger than the other =HAMAMELIDACEAE=, p. 51.

123b. Leaves symmetrical or nearly so at the base --124.

124a. Lateral leaf-veins ending in the leaf-teeth --125.

124b. Lateral veins not ending in the teeth
42b, in =ROSACEAE=, p. 55.

125a. Bark smooth and fluted on the large stems
1b, in =BETULACEAE=, p. 21.

125b. Bark rough or warty or glandular --126.

126a. Leaves 4 cm. long or less 3a, in =BETULACEAE=, p. 22.

126b. Leaves 5 cm. long or more 9b, in =BETULACEAE=, p. 22.

127a. Pith 3-angled 6a, in =BETULACEAE=, p. 22.

127b. Pith 5-angled 13b, in =FAGACEAE=, p. 23.

127c. Pith cylindrical --128.

128a. Leaves finely serrate 42b, in =ROSACEAE=, p. 55.

128b. Leaves coarsely or doubly serrate 41a, in =ROSACEAE=, p. 54.

129a. Leaves coarsely or doubly serrate --130.

129b. Leaves simply serrate --131.

130a. Leaves 2-ranked, i. e., in two longitudinal rows, with the
third leaf directly over the first
9b, in =BETULACEAE=, p. 22.

130b. Leaves not 2-ranked 41a, in =ROSACEAE=, p. 54.

131a. Leaves with glands on the petiole or at the base of the leaf-blade
--132.

131b. Leaves with small dark glands on the upper side of the mid-vein
42a, in =ROSACEAE=, p. 54.

131c. Leaves without glands --133.

132a. Willows; with usually slender leaves, frequently conspicuous
broad stipules, and lateral buds protected by a single
external bud-scale 13, in =SALICACEAE=, p. 20.

132b. Plums and cherries; with leaves lanceolate or broader, and
stipules minute and falling early in the season; lateral buds
with more than one bud-scale 30, in =ROSACEAE=, p. 54.

133a. With stipules or with stipular scars indicating where stipules
have been detached --134.

133b. Without stipules or stipular scars --138.

134a. With three bundle-scars in each leaf-scar --135.

134b. With one bundle-scar in each leaf-scar --136.

135a. Willows; usually with slender leaves and twigs and frequently with
large conspicuous stipules; lateral buds covered by a single
external bud-scale 13, in =SALICACEAE=, p. 20.

135b. Juneberries; with oblong or ovate leaves and small stipules which
fall early; lateral buds with more than one external scale
42b, in =ROSACEAE=, p. 55.

136a. Leaves mostly entire, only a few here and there with low
teeth 1a, in =AQUIFOLIACEAE=, p. 69.

136b. Leaves sharply toothed --137.

137a. Axillary buds superposed, i. e., with a second one just above the
first 1b, in =AQUIFOLIACEAE=, p. 69.

137b. Axillary buds not superposed 2b, in =RHAMNACEAE=, p. 71.

138a. Leaves with purple petioles, which are at least one-fourth as
long as the blade 1a, in =AQUIFOLIACEAE=, p. 69.

138b. Leaves short-petioled or sessile --139.

139a. Stems erect and straight, unbranched or with very few branches
27, in =ROSACEAE=, p. 53.

139b. Stems more or less crooked and freely branched, making a spreading
shrub 25, in =ERICACEAE=, p. 86.

--140--

140a. Flowers appearing in autumn, after the leaves have fallen
=HAMAMELIDACEAE=, p. 51.

140b. Flowers appearing in spring, before the leaves have opened
--141.

141a. Flowers in catkins, without brightly colored or petal-like parts
--142.

141b. Flowers not in catkins, either with or without brightly colored or
petal-like parts --149.

142a. Leaves 2-ranked, as shown by the arrangement of buds and
leaf-scars in two longitudinal rows, so that the third bud is
directly over the first --143.

142b. Leaves and leaf-scars not 2-ranked --146.

143a. Bundle-scars three in each leaf-scar --144.

143b. Bundle-scars several in each leaf-scar 2b, in =URTICACEAE=, p. 23.

144a. Leaf-buds with only 1-3 visible bud-scales
10, in =BETULACEAE=, p. 22.

144b. Leaf-buds with more than 3 visible scales --145.

145a. Bark of the branches smooth and dark gray, the larger stems fluted
with projecting longitudinal ridges 1b, in =BETULACEAE=, p. 21.

145b. Branches without projecting ridges 4, in =BETULACEAE=, p. 22.

146a. Pith 3-angled 8, in =BETULACEAE=, p. 22.

146b. Pith 5-angled 13b, in =FAGACEAE=, p. 23.

146c. Pith cylindrical --147.

147a. Visible outer bud-scales 2 or more --148.

147b. Buds with a single visible outer scale
13, in =SALICACEAE=, p. 20.

148a. Bundle-scars 3 in each leaf-scar =MYRICACEAE=, p. 20.

148b. Bundle-scars more than 3 in each leaf-scar
2b, in =URTICACEAE=, p. 23.

149a. Flowers dark red-purple, about 3 cm. wide =ANONACEAE=, p. 40.

149b. Flowers bright pink, irregular, about 1 cm. wide
3a, in =LEGUMINOSAE=, p. 58.

149c. Flowers white, with 5 conspicuous petals --150.

149d. Flowers greenish or yellowish, small, inconspicuous --152.

150a. Ovary 1, superior, i. e., in the center of the flower and not
attached to surrounding parts 36, in =ROSACEAE=, p. 54.

150b. Ovary inferior, appearing as a swelling below the calyx at
the apex of the pedicel --151.

151a. Flowers in racemes or solitary 42b, in =ROSACEAE=, p. 55.

151b. Flowers in flattened or rounded branching clusters
42a, in =ROSACEAE=, p. 55.

152a. Stems thorny 1a, in =RUTACEAE=, p. 65.

152b. Stems not thorny --153.

153a. Bark pleasantly aromatic when crushed; perianth with 6 parts
--154.

153b. Bark not pleasantly aromatic; perianth with 4 short lobes
=THYMELAEACEAE=, p. 77.

154a. Flowers in sessile lateral clusters
1a, in =LAURACEAE=, p. 41.

154b. Flowers in peduncled terminal clusters
1b, in =LAURACEAE=, p. 41.

--155--

155a. Leaves narrow, needle-like or scale-like, mostly evergreen --54.

155b. Leaves broader, flat or rolled, but not needle-like or scale-like
--156.

156a. Twining or climbing vines --56.

156b. Not twining or climbing --157.

157a. Leaves opposite --158.

157b. Leaves alternate --165.

158a. Leaves compound --68.

158b. Leaves simple --159.

159a. Leaves broad, palmately lobed --160.

159b. Leaves not palmately lobed --161.

160a. Flowers greenish-yellow, in racemes or panicles
2a, in =ACERACEAE=, p. 70.

160b. Flowers white, in rounded or flattened clusters
22a, in =CAPRIFOLIACEAE=, p. 111.

161a. Flowers in close clusters, subtended by four large white
petal-like bracts 4b, in =CORNACEAE=, p. 83.

161b. Flowers small, white, in dense spherical heads
1a, in =RUBIACEAE=, p. 108.

161c. Flowers not in dense heads, and not subtended by petal-like bracts
--162.

162a. Petals separate from each other --163.

162b. Petals united with each other --164.

163a. Flowers dark purple-red 1b, in =CELASTRACEAE=. p. 69.

163b. Flowers bright yellow 1a, in =HYPERICACEAE=, p. 73.

163c. Flowers pink-purple; aquatic shrubs 1a, in =LYTHRACEAE=, p. 77.

163d. Flowers white 5, in =CORNACEAE=, p. 83.

163e. Flowers minute, greenish; twigs usually thorny
1b, in =RHAMNACEAE=, p. 71.

163f. Flowers small, yellowish; leaves silvery beneath
=ELAEAGNACEAE=, p. 77.

164a. Stamens 2 1a, in =OLEACEAE=, p. 88.

164b. Stamens 4 or 5 11, in =CAPRIFOLIACEAE=, p. 110.

164c. Stamens 10 18a, in =ERICACEAE=, p. 85.

165a. Leaves once-compound --166.

165b. Leaves simple --172.

165c. Leaves twice- or thrice-compound 4a, in =ARALIACEAE=, p. 80.

166a. Flowers small, greenish or greenish-yellow --167.

166b. Flowers conspicuous, white, or brightly colored --170.

167a. Stems thorny 1a, in =RUTACEAE=, p. 65.

167b. Stems not thorny --168.

168a. Leaflets 3, entire or minutely toothed
1b, in =RUTACEAE=, p. 65.

168b. Leaflets 3, conspicuously toothed
1b, in =ANACARDIACEAE=, p. 68.

168c. Leaflets more than 3 --169.

169a. Leaflets entire except for 1-4 large glandular teeth near their
base =SIMARUBACEAE=, p. 65.

169b. Leaflets entire, or toothed for their entire length
=ANACARDIACEAE=, p. 68.

170a. Flowers with a single bright-blue petal
8a, in =LEGUMINOSAE=, p. 58.

170b. Flowers with several petals --171.

171a. Flowers regular 3, in =ROSACEAE=, p. 51.

171b. Flowers irregular, the upper petal the largest
4, in =LEGUMINOSAE=, p. 58.

172a. Leaves minute, scale-like, appressed
2a, in =CISTACEAE=, p. 74.

172b. Leaves 3-10 mm. long, spreading, completely rolled into a
tube =EMPETRACEAE=, p. 68.

172c. Leaves normal in shape, green in color --173.

173a. Leaves evergreen, as shown by their presence on the older parts of
the stem 4b, in =ERICACEAE=, p. 84.

173b. Leaves deciduous --174.

174a. Flowers in catkins, without petal-like parts --142.

174b. Flowers not in catkins, either with or without petal-like
parts --175.

175a. Flowers small, inconspicuous, yellowish or greenish in color
--176.

175b. Flowers white or colored, with conspicuous petals --180.

176a. Leaves broad and palmately lobed; stem thorny
1a, in =ARALIACEAE=, p. 80.

176b. Leaves entire, toothed, or with 2-3 entire lobes; stem not
thorny --177.

177a. Flowers in small axillary clusters; foliage not spicy-aromatic
--178.

177b. Flowers in clusters terminating last year's twigs; foliage
spicy-aromatic 1b, in =LAURACEAE=, p. 41.

178a. Petals none; sepals present 2b, in =RHAMNACEAE=, p. 71.

178b. Petals present but small --179.

179a. A stamen in front of each petal 2a, in =RHAMNACEAE=, p. 71.

179b. A stamen between each two petals =AQUIFOLIACEAE=, p. 69.

180a. Petals united with each other; stamens 8-10
24, in =ERICACEAE=, p. 86.

180b. Petals separate from each other --181.

181a. Petals 4 --182.

181b. Petals 5 --183.

181c. Petal-like sepals 6; real petals none; foliage spicy-aromatic
1b, in =LAURACEAE=, p. 41.

181d. Petals 6; sepals also present --187.

182a. Flowers in late spring or early summer
2a, in =CORNACEAE=, p. 83.

182b. Flowers in autumn =HAMAMELIDACEAE=, p. 51.

183a. Corolla irregular, the upper petal largest
3b, in =LEGUMINOSAE=, p. 58.

183b. Corolla regular, all petals alike in size and shape --184.

184a. Stamens 5 --185.

184b. Stamens 10 or more 24, in =ROSACEAE=, p. 53.

185a. Flowers in loose racemes or axillary clusters
2, in =SAXIFRAGACEAE=, p. 49.

185b. Flowers in branching clusters --186.

186a. Leaves palmately lobed; stem thorny
1a, in =ARALIACEAE=, p. 80.

186b. Leaves not lobed; stem not thorny
1b, in =RHAMNACEAE=, p. 71.

187a. Flowers dark red-purple =ANONACEAE=, p. 40.

187b. Flowers yellow 2a, in =BERBERIDACEAE=, p. 40.

GROUP 2, UNUSUAL PLANTS

1a. Small brown leafless plants, growing as parasites on the tamarack or
black spruce =LORANTHACEAE=, p. 25.

1b. Aquatic plants, with all or most of the leaves submerged, or
leafless --2.

1c. Aquatic plants, with the leaves or the whole plant floating on or
near the surface --20.

1d. Terrestrial or marsh plants, without floating or submerged leaves
--29.

2a. Submerged aquatics, without leaves --3.

2b. Submerged aquatics, with the leaves linear or dissected --4.

3a. Flowers showy, yellow or purple =LENTIBULARIACEAE=, p. 105.

3b Flowers small and inconspicuous, sessile, purplish or greenish
3a, in =HALORAGIDACEAE=, p. 79.

4a. Leaves linear or lanceolate, not lobed or dissected --5.

4b. Leaves more or less lobed or dissected --13.

5a. Leaves all basal --6.

5b. Stem-leaves present --7.

6a. Flowers blue, 1 cm. long or more; leaves cylindrical, blunt,
hollow, partitioned lengthwise 1a, in =LOBELIACEAE=, p. 113.

6b. Flowers yellow; leaves minute =LENTIBULARIACEAE=, p. 105.

6c. Flowers white, in clusters; leaves linear-lanceolate, acute,
not hollow 1b, in =ALISMACEAE=, p. 3.

6d. Flowers greenish, solitary at the end of elongated peduncles;
leaves very long and ribbon-like, flat or trough-shape
1a, in =HYDROCHARITACEAE=, p. 3.

6e. Flowers minute, whitish or lead-color, in heads
=ERIOCAULACEAE=, p. 9.

7a. Leaves alternate --8.

7b. Leaves opposite --10.

7c. Leaves whorled --12.

8a. Leaves with thin sheathing stipules 1b, in =NAJADACEAE=, p. 2.

8b. Leaves without stipules --9.

9a. Flowers greenish, in a head =SPARGANIACEAE=, p. 2.

9b. Flowers pale yellow 1b, in =PONTEDERIACEAE=, p. 10.

10a. Leaves serrate 2b, in =NAJADACEAE=, p. 2.

10b. Leaves entire --11.

11a. Leaves 2 cm. long or less =CALLITRICHACEAE=, p. 68.

11b. Leaves thread-like, 2-8 cm. long 2a, in =NAJADACEAE=, p. 2.

11c. Leaves linear to elliptical, more than 2 cm. long
1b, in =NAJADACEAE=, p. 2.

12a. Leaves in whorls of 3, abruptly widened at the base
2b, in =NAJADACEAE=, p. 2.

12b. Leaves in whorls of 3, widest near the middle
1b, in =HYDROCHARITACEAE=, p. 3.

12c. Stems straight and erect, at leaves the flowers emerged;
leaves in whorls of 4 or more 2a, in =HALORAGIDACEAE=, p. 79.

13a. Leaves with numerous small bladders attached, each bladder 1-3 mm.
long =LENTIBULARIACEAE=, p. 105.

13b. Leaves without bladders --14.

14a. Leaves alternate --15.

14b. Leaves opposite or whorled --18.

15a. Delicate and rare plants growing attached to stones in running
water =PODOSTEMACEAE=, p. 48.

15b. Plants 2 dm. high or more, with roots in mud or sand --16.

16a. Leaves once-pinnate --17.

16b. Leaves 2-3 times pinnate 15b, in =UMBELLIFERAE=, p. 81.

16c. Leaves palmately dissected 1b, in =RANUNCULACEAE=, p. 35.

17a. Taste peppery or mustardy 34, in =CRUCIFERAE=, p. 45.

17b. Taste not peppery or mustardy 1a, in =HALORAGIDACEAE=, p. 79.

18a. Leaves pinnately compound 3b, in =HALORAGIDACEAE=, p. 79.

18b. Leaves palmately compound --19.

19a. Leaves opposite or in whorls of four 119a, in =COMPOSITAE=, p. 123.

19b. Leaves in whorls of 5-12 =CERATOPHYLLACEAE=, p. 34.

20a. Plants small, flattened, rounded or ovate, without distinction
of stem and leaf; the whole plant floating on or near the
surface =LEMNACEAE=, p. 9.

20b. Plant attached to the soil, with differentiated stem and
leaves --21.

21a. Leaves on long slender stalks, which bear also a cluster of slender
tubers near the leaf-base; leaves heart-shape
1b, in =GENTIANACEAE=, p. 88.

21b. Leaf-stalks without a cluster of tubers --22.

22a. Leaves all basal --23.

22b. Stem-leaves present --24.

23a. Leaves parallel-veined 1b, in =ALISMACEAE=, p. 3.

23b. Leaves net-veined 1b, in =NYMPHAEACEAE=, p. 35.

24a. Leaves opposite or whorled --25.

24b. Leaves alternate --26.

25a. Leaves less than 2 cm. long =CALLITRICHACEAE=, p. 68.

25b. Leaves more than 2 cm. long 1b, in =NAJADACEAE=, p. 2.

26a. Leaves attached by the center to the stalk
2b, in =NYMPHAEACEAE=, p. 35.

26b. Leaves attached by the margin --27.

27a. Leaves parallel-veined --28.

27b. Leaves net-veined, with a single mid-vein; lanceolate or elliptical
in outline 29b, in =POLYGONACEAE=, p. 28.

28a. Leaves not over 2 dm. long 1b, in =NAJADACEAE=, p. 2.

28b. Leaves very long and grass-like 14a, in =GRAMINEAE=, p. 5.

29a. Brown, yellow, or white plants, without green color --30.

29b. Plants with normal green color, at least in some parts --33.

30a. Stemless and leafless plants, consisting of flowers only and
partly underground 4a, in =ARACEAE=, p. 8.

30b. Stems climbing on other plants 1b, in =CONVOLVULACEAE=, p. 91.

30c. Stem and flower-stalks erect, not climbing --31.

31a. Corolla regular; stamens 6-12 1a, in =ERICACEAE=, p. 84.

31b. Corolla irregular --32.

32a. Sepals and petals each 3; flowers in simple racemes
5a, in =ORCHIDACEAE=, p. 16.

32b. Sepals 5; corolla of united petals =OROBANCHACEAE=, p. 106.

33a. Stem thick and fleshy, leafless, thorny =CACTACEAE=, p. 77.

33b. Stem not thorny --34.

34a. Leaves none --35.

34b. Leaves reduced to small scales --40.

34c. Leaves thick and fleshy --44.

34d. Leaves hollow --45.

34e. Leaves small, all basal, bearing large glandular hairs on the
upper surface =DROSERACEAE=, p. 48.

35a. Stem none, the flowers appearing at or partially beneath the
surface of the soil 4a, in =ARACEAE=, p. 8.

35b. Stem present --36.

36a. Stem freely branched 2a, in =LILIACEAE=, p. 10.

36b. Stem unbranched, except possibly in the flower-clusters
--37.

37a. Flowers greenish or brownish, without obvious colored petals --38.

37b. Flowers with conspicuous white or colored petals --39.

38a. Each flower with 6 small chaffy petals
4, in =JUNCACEAE=, p. 10.

38b. Petals none; each flower in the axil of a single chaffy bract
2a, in =CYPERACEAE=, p. 7.

39a. Flowers regular 34a, in =LILIACEAE=, p. 11.

39b. Flowers irregular 10a, in =ORCHIDACEAE=, p. 16.

40a. Stem erect, unbranched or with one or two branches only --41.

40b. Stem freely branched --42.

41a. Plants of moist soil, with opposite scales; corolla regular, with 4
petal-like lobes 1a, in =GENTIANACEAE=, p. 88.

41b. Swamp plants, with a few alternate scales; corolla irregular
=LENTIBULARIACEAE=, p. 105.

42a. Leaves numerous and close, concealing the stem
2a, in =CISTACEAE=, p. 74.

42b. Leaves spreading, not concealing the stem --43.

43a. Leaf-scales in small clusters; flowers greenish, with 6 petals
2a, in =LILIACEAE=, p. 10.

43b. Leaf-scales distinctly opposite; petals 5, yellow
7a, in =HYPERICACEAE=, p. 74.

44a. Sepals 2 3, in =PORTULACACEAE=, p. 34.

44b. Sepals 4 or 5 =CRASSULACEAE=, p. 48.

45a. Leaves pitcher-shape, open at the top =SARRACENIACEAE=, p. 48.

45b. Leaves tubular, closed at the end 37b, in =LILIACEAE=, p. 13.

GROUP 3, MONOCOTYLEDONES

1a. Twining plants, with flowers in panicles or racemes

=DIOSCOREACEAE=, p. 14.

1b. Plants with milky juice

13a, in =COMPOSITAE=, p. 115.

1c. Plants not twining (some climb by tendrils) and not with milky
juice. --2.

2a. Flowers in close spikes or heads, surrounded or subtended by a
green or colored bract, the whole resembling a single flower;
petals minute or wanting; leaves broad, not grass-like, linear,
or sword-shape =ARACEAE=, p. 8.

2b. Plants with narrow, linear, grass-like, or sword-shape leaves
(a few species of Carex have broader, lanceolate to ovate
leaves); flowers greenish, yellowish, or brownish, never
brightly colored, and frequently dry or chaffy in texture;
perianth small or wanting; individual flowers inconspicuous in
size, but sometimes grouped into conspicuous clusters --3.

2c. Plants with leaves of various widths, but the flowers petaloid,
i. e., with a white or colored, more or less conspicuous
perianth, and never chaffy in texture. In a few cases the
flowers are greenish, but the size and conspicuousness of the
perianth identifies them in this class --9.

3a. Flowers in the axils of dry, membranous or chaffy scales, which are
regularly arranged into spikes or spikelets of uniform size and
structure, which are variously grouped or clustered; fruit an
achene; grasses and sedges, with joined stems and sheathing leaves,
or leafless and the stems not jointed --4.

3b. Flowers not subtended individually by dry, membranous, or chaffy
scales, and otherwise not agreeing with 3a --5.

4a. Leaf-sheaths split on the side opposite the leaf; leaves
usually 2-ranked, i. e., in 2 longitudinal rows with the third
leaf above the first; stems rounded or flat, never triangular,
usually hollow =GRAMINEAE=, p. 4.

4b. Leaf-sheaths closed into a continuous tube; leaves usually
3-ranked; stems frequently triangular, usually solid
=CYPERACEAE=, p. 7.

5a. Flowers in dense spikes --6.

5b. Flowers in heads, racemes, or panicles --7.

6a. Spike terminal, with pistillate flowers at the base and
staminate ones at the apex =TYPHACEAE=, p. 2.

6b. Spike short, apparently lateral, near the apex of the stem
3a, in =ARACEAE=, p. 8.

7a. Flowers in globose heads which are arranged in spikes, the lowest
heads pistillate, the upper staminate; ovary 1-celled
=SPARGANIACEAE=, p. 2.

7b. Flowers in globose woolly heads terminating leafless unbranched
stalks =ERIOCAULACEAE=, p. 9.

7c. Flowers in a spike-like raceme; ovaries 3-6, separate or nearly so
=JUNCAGINACEAE=, p. 3.

7d. Flowers in heads or panicles, all perfect, not woolly, with one
ovary --8.

8a. Leaves less than 1 cm. wide, or none; divisions of the perianth
6 =JUNCACEAE=, p. 10.

8b. Leaves 2 cm. wide or more; petals 5
2a, in =UMBELLIFERAE=, p. 80.

9a. Flowers regular, with all the petals of approximately the same size
and shape --10.

9b. Flowers irregular, with the petals of each flower not of the same
size or shape --22.

10a. Ovaries 3 or more, separate or barely united with each other
at the base --11.

10b. Ovary one in each flower --12.

11a. Ovaries 3-6 in number; flowers in spikes or racemes; leaves linear
=JUNCAGINACEAE=, p. 3.

11b. Ovaries more than 6 =ALISMACEAE=, p. 3.

12a. Flowers or flower-clusters lateral, axillary or apparently so
--13.

12b. Flowers or flower-clusters terminal or on leafless stalks
--14.

13a. Leaves minute and scale-like; flowers greenish-yellow
2a, in =LILIACEAE=, p. 10.

13b. Leaves linear, grass-like 3b, in =IRIDACEAE=, p. 13.

13c. Leaves lanceolate or broader, not grass-like or scale-like
2b, in =LILIACEAE=, p. 10.

14a. Divisions of the perianth 5-12 cm. long --15.

14b. Divisions of the perianth less than 5 cm. long --16.

15a. Flowers blue, or blue marked with yellow 1a, in =IRIDACEAE=, p. 15.

15b. Flowers not blue 12a, in =LILIACEAE=, p. 11.

16a. Flowers solitary --17.

16b. Flowers 2 or more, in some kind of a cluster --18.

17a. Leaves 2, broadly heart-shape, basal, on long stalks
1b, in =ARISTOLOCHIACEAE=, p. 25.

17b. Leaves not heart-shape 20, 20, in =LILIACEAE=, p. 12.

18a. Divisions of the perianth (4 to 6) all essentially alike --19.

18b. Perianth differentiated into sepals and 2 or 3 colored petals
--21.

19a. Flowers in umbels --20.

19b. Flowers in dense round heads; petals 5
2a, in =UMBELLIFERAE=, p. 80.

19c. Flowers in spikes, racemes, or panicles 38, in =LILIACEAE=, p. 13.

20a. Ovary inferior, appearing below the perianth as a swelling at
the apex of the stalk; flowers bright yellow; leaves linear
=AMARYLLIDACEAE=, p. 14.

20b. Ovary inferior; flowers blue or white, terminating a flattened
winged leafless flower-stalk 3a, in =IRIDACEAE=, p. 15.

20c. Ovary superior, i. e., in the center of the flower and
separate from the perianth 31, in =LILIACEAE=, p. 13.

21a. Flowers in dense heads, yellow, 1 cm. wide or smaller
=XYRIDACEAE=, p. 9.

21b. Flowers in umbels, blue or white, 2 cm. wide or larger
=COMMELINACEAE=, p. 9.

22a. Flowers blue; ovary superior (defined under _20c_); stamens
distinct from the other parts of the flower --23.

22b. Ovary inferior (defined under _20a_); floral structure
complex; stamens attached to other parts of the flower and not
resembling ordinary stamens in form or structure
=ORCHIDACEAE=, p. 15.

23a. Leaves triangular-heart-shape at base; marsh plants
1a, in =PONTEDERIACEAE=, p. 10.

23b. Leaves not heart-shape at base =COMMELINACEAE=, p. 9.

GROUP 4, DICOTYLEDONES

1a. Foliage leaves all or principally basal; flower-stalk either
completely leafless, or bearing a single pair of opposite leaves
only. Bracts and scale-leaves are not considered foliage leaves --2.

1b. Stem-leaves present on the stem, either one or more in number, and
not limited to a single opposite pair --3.

2a. Leaves compound --7.

2b. Leaves simple --18.

3a. Stem-leaves all or chiefly opposite or whorled (the bracts of the
flower clusters may be alternate) --4.

3b. Stem-leaves all or chiefly alternate --5.

4a. Flowers small and inconspicuous, the perianth none or greenish
or chaffy, and never petal-like in appearance --50.

4b. Flowers with a white or colored petal-like perianth --66.

5a. Flowers small and inconspicuous, without any white or colored
petal-like perianth --118.

5b. Flowers large or small, but with a white or colored petal-like
perianth --6.

6a. Flowers small, not exceeding 3 mm. in length or breadth --144.

6b. Flowers larger, more than 3 mm. in length or breadth --166.

--7--

7a. Leaves twice to three times compound or dissected --8.

7b. Leaves once-compound --11.

8a. Flowers in racemes 2b, in =FUMARIACEAE=, p. 41.

8b. Flowers in umbels --9.

9a. Flowers about 3 mm. wide, white or greenish-white --10.

9b. Flowers 10-20 mm. wide, conspicuous 45b, in =RANUNCULACEAE=, p. 39.

10a. Leaflets 5-15 cm. long 5b, in =ARALIACEAE=, p. 80.

10b. Leaflets not over 2 cm. long 16a, in =UMBELLIFERAE=, p. 81.

11a. Leaflets 2 3a, in =BERBERIDACEAE=, p. 40.

11b. Leaflets three or more --12.

12a. Leaflets entire or very finely toothed --13.

12b. Leaflets coarsely toothed or lobed --15.

13a. Flowers irregular, in dense head-like umbels
37a, in =LEGUMINOSAE=, p. 61.

13b. Flowers consisting of a greenish or purplish bract wholly or partly
enclosing a fleshy spike 2, in =ARACEAE=, p. 8.

13c. Flowers regular, solitary or in loose clusters --14.

14a. Leaflets reverse heart-shape, not over 2 cm. long
=OXALIDACEAE=, p. 64.

14b. Leaflets 4-10 cm. long 1c, in =GENTIANACEAE=, p. 88.

15a. Flowers with colored or white petals and green or colored sepals
--16.

15b. Flowers with one kind of perianth only (calyx), with broad and
petal-like parts 32, in =RANUNCULACEAE=, p. 38.

15c. Flowers with white petal-like sepals and small inconspicuous petals
38b, in =RANUNCULACEAE=, p. 39.

16a. Petals and sepals each 4 31, in =CRUCIFERAE=, p. 44.

16b. Petals and sepals each 5 or more --17.

17a. Leaves with stipules =ROSACEAE=, p. 51.

17b. Leaves without stipules 23b, in =RANUNCULACEAE=, p. 37.

--18--

18a. Stem-leaves a single opposite pair (basal leaves may also be
present) --19.

18b. Stem-leaves none --23.

19a. Leaves entire --20.

19b. Leaves toothed or lobed --21.

20a. Flowers solitary; leaves broadly kidney-shape
=ARISTOLOCHIACEAE=, p. 25.

20b. Flowers in racemes; leaves linear or lanceolate
=PORTULACACEAE=, p. 34.

21a. Flowers in racemes; petals deeply toothed
23b, in =SAXIFRAGACEAE=, p. 51.

21b. Flowers solitary or few in a cluster; petals entire or nearly so
--22.

22a. Petals 5 =GERANIACEAE=, p. 64.

22b. Petals 6 or more 2b, in =BERBERIDACEAE=, p. 40.

23a. Flowers or flower-clusters sessile, at or partly beneath the
surface of the ground 4a, in =ARACEAE=, p. 8.

23b. Flowers or flower-heads solitary at the ends of the flower-stalks
--24.

23b. Flowers or flower-heads numerous or several on each flower-stalk
--38.

24a. Flowers yellow --25.

24b. Flowers not yellow --29.

25a. Juice milky 16, in =COMPOSITAE=, p. 115.

25b. Juice not milky --26.

26a. Aquatic or mud plants, with large entire leaves 1-4 dm. wide
=NYMPHAEACEAE=, p. 35.

26b. Land plants, with smaller or lobed leaves --27.

27a. Flower-stalk scaly 110, in =COMPOSITAE=, p. 122.

27b. Flower-stalk bare or with 1 to 2 minute bracts --28.

28a. Flowers regular 10, in =RANUNCULACEAE=, p. 36.

28b. Flowers irregular, with a spur 3a, in =VIOLACEAE=, p. 75.

29a. Flowers obviously irregular, with a spur --30.

29b. Flowers regular or nearly so, without a spur --31.

30a. Leaves sessile or nearly so; stamens 2
=LENTIBULARIACEAE=, p. 105.

30b. Leaves petioled; stamens 5 =VIOLACEAE=, p. 75.

31a. Flowers 3 mm. wide or smaller; leaves thread-like
16a, in =SCROPHULARIACEAE=, p. 103.

31b. Flowers 6 mm. wide or larger --32.

32a. Ovary 1 --33.

32b. Ovaries numerous --37.

33a. Leaves lobed or cleft --34.

33b. Leaves entire or toothed --35.

34a. Leaves deeply 2-cleft; stamens 8
3a, in =BERBERIDACEAE=, p. 40.

34b. Leaf 1, palmately lobed; stamens numerous
1a, in =PAPAVERACEAE=, p. 41.

35a. Flowers dull red =ARISTOLOCHIACEAE=, p. 25.

35b. Flowers white or pinkish --36.

36a. Leaves entire; stamens with good anthers 5
13, in =SAXIFRAGACEAE=, p. 50.

36b. Leaves minutely toothed; stamens 8-10
14a, in =ERICACEAE=, p. 85.

37a. Leaves lobed or divided =RANUNCULACEAE=, p. 35.

37b. Leaves crenate or toothed 64a, in =ROSACEAE=, p. 56.

--38--

38a. Flowers of the composite type, with several or many small
flowerets closely aggregated into a dense head surrounded by a
calyx-like involucre of small bracts
10, in =COMPOSITAE=. p. 114.

38b. Flowers separate; variously clustered, but never crowded into
involucred heads --39.

39a. Flowers in dense close spikes --40.

39b. Flowers in open loose clusters --42.

40a. Flower-stalk leafless below the spike
=PLANTAGINACEAE=, p. 107.

40b. Flower-stalk with several bracts --41.

41a. Leaves entire 9c, in =ORCHIDACEAE=, p. 16.

41b. Leaves toothed 6a, in =SCROPHULARIACEAE=, p. 102.

42a. Flowers in umbels --43.

42b. Flowers in racemes, panicles, flat-topped clusters, or merely
1 or 2 --45.

43a. Leaves almost round, peltate, palmately veined
3a, in =UMBELLIFERAE=, p. 80.

43b. Leaves at least twice as long as broad, with a single mid-vein
--44.

44a. Stamens 5 =PRIMULACEAE=, p. 87.

44b. Stamens 10 15, in =ERICACEAE=, p. 85.

45a. Leaves cylindrical, hollow, obtuse. 1a, in =LOBELIACEAE=, p. 113.

45b. Leaves beset on the upper side with long glandular hairs; bog plant
with flowers in racemes =DROSERACEAE=, p. 48.

45c. Leaves flat, pubescent or smooth, but not with long glandular hairs
--46.

46a. Sepals and petals each 4 53, in =CRUCIFERAE=, p. 46.

46b. Sepals and petals each 5 --47.

46c. Sepals 6; petals none; flowers minute, green; leaves
frequently lobed at the base 4, in =POLYGONACEAE=, p. 25.