TO
M. R. S.
THE WISE AND KIND FRIEND OF THIRTY YEARS
THIS BOOK IS DEDICATED
WITH GRATITUDE AND AFFECTION

PREFACE TO THE SECOND EDITION

The studies of the trees of North America (exclusive of Mexico) which have been carried on by the agents and correspondents of the Arboretum in the sixteen years since the publication of the Manual of the Trees of North America have increased the knowledge of the subject and made necessary a new edition of this Manual. The explorations of these sixteen years have added eighty-nine species of trees and many recently distinguished varieties of formerly imperfectly understood species to the silva of the United States, and made available much additional information in regard to the geographical distribution of American trees. Further studies have made the reduction of seven species of the first edition to varieties of other species seem desirable; and two species, Amelanchier obovalis and Cercocarpus parvifolius, which were formerly considered trees, but are more properly shrubs, are omitted. The genus Anamomis is now united with Eugenia; and the Arizona Pinus strobiformis Sarg. (not Engelm.) is now referred to Pinus flexilis James.

Representatives of four Families and sixteen Genera which did not appear in the first edition are described in the new edition in which will be found an account of seven hundred and seventeen species of trees in one hundred and eighty-five genera, illustrated by seven hundred and eighty-three figures, or one hundred and forty-one figures in addition to those which appeared in the first edition.

An International Congress of Botanists which assembled in Vienna in 1905, and again in Brussels in 1910, adopted rules of nomenclature which the world, with a few American exceptions, has now generally adopted. The names used in this new Manual are based on the rules of this International Congress. These are the names used by the largest number of the students of plants, and it is unfortunate that the confusion in the names of American trees must continue as long as the Department of Agriculture, including the Forest Service of the United States, uses another and now generally unrecognized system.

The new illustrations in this edition are partly from drawings made by Charles Edward Faxon, who died before his work was finished; it was continued by the skillful pencil of Mary W. Gill, of Washington, to whom I am grateful for her intelligent coöperation.

It is impossible to name here all the men and women who have in the last sixteen years contributed to this account of American trees, and I will now only mention Mr. T. G. Harbison and Mr. E. J. Palmer, who as agents of the Arboretum have studied for years the trees of the Southeastern States and of the Missouri-Texas region, Professor R. S. Cocks, of Tulane University, who has explored carefully and critically the forests of Louisiana, and Miss Alice Eastwood, head of the Botanical Department of the California Academy of Sciences, who has made special journeys in Alaska and New Mexico in the interest of this Manual. Mr. Alfred Rehder, Curator of the Herbarium of the Arboretum, has added to the knowledge of our trees in several Southern journeys; and to him I am specially indebted for assistance and advice in the preparation of the keys to the different groups of plants found in this volume.

This new edition of the Manual contains the results of forty-four years of my continuous study of the trees of North America carried on in every part of the United States and in many foreign countries. If these studies in any way serve to increase the knowledge and the love of trees I shall feel that these years have not been misspent.

C. S. Sargent. Arnold Arboretum
September, 1921

PREFACE

In this volume I have tried to bring into convenient form for the use of students the information concerning the trees of North America which has been gathered at the Arnold Arboretum during the last thirty years and has been largely elaborated in my Silva of North America.

The indigenous trees of no other region of equal extent are, perhaps, so well known as those that grow naturally in North America. There is, however, still much to be learned about them. In the southern states, one of the most remarkable extratropical regions in the world in the richness of its arborescent flora, several species are still imperfectly known, while it is not improbable that a few may have escaped entirely the notice of botanists; and in the northern states are several forms of Cratægus which, in the absence of sufficient information, it has been found impracticable to include in this volume. Little is known as yet of the silvicultural value and requirements of North American trees, or of the diseases that affect them; and one of the objects of this volume is to stimulate further investigation of their characters and needs.

The arrangement of families and genera adopted in this volume is that of Engler & Prantl’s Die Natürlichen Pflanzenfamilien, in which the procession is from a simpler to a more complex structure. The nomenclature is that of The Silva of North America. Descriptions of a few species of Cratægus are now first published, and investigations made since the publication of the last volume of The Silva of North America, in December, 1902, have necessitated the introduction of a few additional trees described by other authors, and occasional changes of names.

An analytical key to the families, based on the arrangement and character of the leaves, will lead the reader first to the family to which any tree belongs; a conspectus of the genera, embodying the important and easily discovered contrasting characters of each genus and following the description of each family represented by more than one genus, will lead him to the genus he is trying to determine; and a similar conspectus of the species, following the description of the genus, will finally bring him to the species for which he is looking. Further to facilitate the determination, one or more letters, attached to the name of the species in the conspectus following the description of the genus, indicate in which of the eight regions into which the country is divided according to the prevailing character of the arborescent vegetation that species grows (see map forming frontispiece of the volume). For example, the northeastern part of the country, including the high Appalachian Mountains in the southern states which have chiefly a northern flora, is represented by (A), and a person wishing to learn the name of a Pine-tree or of an Oak in that region need occupy himself only with those species which in the conspectus of the genus Quercus or Pinus are followed by the letter (A), while a person wishing to determine an Oak or a Pine-tree in Oregon or California may pass over all species which are not followed by (G), the letter which represents the Pacific coast region south of the state of Washington.

The sign of degrees (°) is used in this work to represent feet, and the sign of minutes (′) inches.

The illustrations which accompany each species and important variety are one half the size of nature, except in the case of a few of the large Pine cones, the flowers of some of the Magnolias, and the leaves and flower-clusters of the Palms. These are represented as less than half the size of nature in order to make the illustrations of uniform size. These illustrations are from drawings by Mr. Faxon, in which he has shown his usual skill and experience as a botanical draftsman in bringing out the most important characters of each species, and in them will be found the chief value of this Manual. For aid in its preparation I am indebted to him and to my other associates, Mr. Alfred Rehder and Mr. George R. Shaw, who have helped me in compiling the most difficult of the keys.

C. S. Sargent. Arnold Arboretum, Jamaica Plain, Mass.
January, 1905.

TABLE OF CONTENTS

Map of North America (exclusive of Mexico) showing the eight regions into which the country is divided according to the prevailing character of the trees Frontispiece Synopsis of the Families of Plants described in this work xi Analytical Key to the Genera of Plants described in this work, based chiefly on the character of their leaves xvi Manual of Trees 1 Gymnospermæ 1 Angiospermæ 96 Monocotyledons 96 Dicotyledons 118 Apetalæ 118 Petalatæ 342 Polypetalæ 342 Gamopetalæ 790 Glossary of Technical Terms 893 Index 899

SYNOPSIS
OF THE FAMILIES OF PLANTS DESCRIBED IN THIS BOOK

Class I. GYMNOSPERMÆ.

Resinous trees; stems formed of bark, wood, or pith, and increasing in diameter by the annual addition of a layer of wood inside the bark; flowers unisexual; stamens numerous; ovules and seeds 2 or many, borne on the face of a scale, not inclosed in an ovary; embryo with 2 or more cotyledons; leaves straight-veined, without stipules.

I. Pinaceæ (p. 1). Flowers usually monœcious; ovules 2 or several; fruit a woody cone (in Juniperus berry-like); cotyledons 2 or many; leaves needle-shaped, linear or scale-like, persistent (deciduous in Larix and Taxodium). II. Taxaceæ (p. 90). Flowers diœcious, axillary, solitary; ovules 1; fruit surrounded by or inclosed in the enlarged fleshy aril-like disk of the flower; cotyledons 2; leaves linear, alternate, persistent.

Class II. ANGIOSPERMÆ.

Carpels or pistils consisting of a closed cavity containing the ovules and becoming the fruit.

Division I. MONOCOTYLEDONS.

Stems with woody fibres distributed irregularly through them, but without pith or annual layers of growth; parts of the flower in 3’s; ovary superior, 3-celled; embryo with a single cotyledon; leaves parallel-veined, persistent, without stipules.

III. Palmæ (p. 96). Ovule solitary; fruit baccate or drupaceous, 1 or rarely 2 or 3-seeded; leaves alternate, pinnate, flabellate or orbicular, persistent. IV. Liliaceæ (p. 110). Ovules numerous in each cell; fruit 3-celled, capsular or baccate; leaves linear-lanceolate.

class="center large b">Division II. DICOTYLEDONS.

Stems formed of bark, wood, or pith, and increasing by the addition of an annual layer of wood inside the bark; parts of the flower mostly in 4’s or 5’s; embryo with a pair of opposite cotyledons; leaves netted-veined.

Subdivision 1. Apetalæ. Flowers without a corolla and sometimes without a calyx.

Section 1. Flowers in unisexual aments (female flowers of Juglans and Quercus solitary or in spikes); ovary inferior (superior in Leitneriaceæ) when a calyx is present.

V. Salicaceæ (p. 119). Flowers diœcious, without a calyx. Fruit a 2—4-valved capsule. Leaves simple, alternate, with stipules, deciduous. VI. Myricaceæ (p. 163). Flowers monœcious or diœcious; fruit a dry drupe, covered with waxy exudations; leaves simple, alternate, resinous-punctate, persistent. VII. Leitneriaceæ (p. 167). Flowers diœcious, the staminate without a calyx; ovary superior; fruit a compressed oblong drupe; leaves alternate, simple, without stipules, deciduous. VIII. Juglandaceæ (p. 168). Flowers monœcious; fruit a nut inclosed in an indehiscent (Juglans) or 4-valved (Carya) fleshy or woody shell; leaves alternate, unequally pinnate without stipules, deciduous. IX. Betulaceæ (p. 200). Flowers monœcious; fruit a nut at the base of an open leaf-like involucre (Carpinus), in a sack-like involucre (Ostrya), in the axil of a scale of an ament (Betula), or of a woody strobile (Alnus); leaves alternate, simple, with stipules, deciduous. X. Fagaceæ (p. 227). Flowers monœcious; fruit a nut more or less inclosed in a woody often spiny involucre; leaves alternate, simple, with stipules, deciduous (in some species of Quercus and in Castanopsis and Lithocarpus persistent).

Section 2. Flowers unisexual (perfect in Ulmus); calyx regular, the stamens as many as its lobes and opposite them; ovary superior, 1-celled; seed 1.

XI. Ulmaceæ (p. 308). Fruit a compressed winged samara (Ulmus), a drupe (Celtis and Trema), or nut-like (Planera), leaves simple, alternate, with stipules, deciduous (persistent in Trema). XII. Moraceæ (p. 328). Flowers in ament-like spikes or heads; fruit drupaceous, inclosed in the thickened calyx and united into a compound fruit, oblong and succulent (Morus), large, dry and globose (Toxylon), or immersed in the fleshy receptacle of the flower (Ficus); leaves simple, alternate, with stipules, deciduous (persistent in Ficus).

Section 3. Flowers usually perfect; ovary superior or partly inferior, 1—4-celled; leaves simple, persistent in the North American species.

XIII. Olacaceæ (p. 336). Calyx and corolla 4—6-lobed; ovary 1—4-celled; fruit a drupe more or less inclosed in the enlarged disk of the flower; leaves alternate or fascicled, without stipules. XIV. Polygonaceæ (p. 338). Calyx 5-lobed; ovary 1-celled; fruit a nutlet inclosed in the thickened calyx; leaves alternate, their stipules sheathing the stems. XV. Nyctaginaceæ (p. 340). Calyx 5-lobed; ovary 1-celled; fruit a nutlet inclosed in the thickened calyx; leaves alternate or opposite, without stipules.

Subdivision 2. Petalatæ. Flowers with both calyx and corolla (without a corolla in Lauraceæ, in Liquidambar in Hamamelidaceæ, in Cercocarpus in Rosaceæ, in Euphorbiaceæ, in some species of Acer, in Reynosia, Condalia, and Krugiodendron in Rhamnaceæ, in Fremontia in Sterculiaceæ, in Chytraculia in Myrtaceæ, in Conocarpus in Combretaceæ and in some species of Fraxinus in Oleaceæ).

Section 1. Polypetalæ. Corolla of separate petals.

A. Ovary superior (partly inferior in Hamamelidaceæ; inferior in Malus, Sorbus, Heteromeles, Cratægus, and Amelanchier in Rosaceæ).

XVI. Magnoliaceæ (p. 342). Flowers perfect; sepals and petals in 3 or 4 rows of 3 each; fruit cone-like, composed of numerous cohering carpels; leaves simple, alternate, their stipules inclosing the leaf-buds, deciduous or rarely persistent. XVII. Anonaceæ (p. 353). Flowers perfect; sepals 3; petals 6 in 2 series; fruit a pulpy berry developed from 1 or from the union of several carpels; leaves simple, alternate, without stipules, deciduous or persistent. XVIII. Lauraceæ (p. 356). Flowers perfect or unisexual; corolla 0; fruit a 1-seeded drupe or berry; leaves simple, alternate, punctate, without stipules, persistent (deciduous in Sassafras). XIX. Capparidaceæ (p. 365). Flowers perfect; sepals and petals 4; fruit baccate, elongated, dehiscent; leaves alternate, simple, without stipules, persistent. XX. Hamamelidaceæ (p. 366). Flowers perfect or unisexual; sepals and petals 5 (corolla 0 in Liquidambar); ovary partly inferior; fruit a 2-celled woody capsule opening at the summit; leaves simple, alternate, with stipules, deciduous. XXI. Platanaceæ (p. 371). Flowers monœcious, in dense unisexual capitate heads; fruit an akene; leaves simple, alternate, with stipules, deciduous. XXII. Rosaceæ (p. 376). Flowers perfect; sepals and petals 5 (petals 0 in Cercocarpus); ovary inferior in Malus, Sorbus, Heteromeles, Cratægus, and Amelanchier; fruit a drupe (Prunus and Chrysobalanus), a capsule (Vauquelinia and Lyonothamnus), an akene (Cowania and Cercocarpus), or a pome (Malus, Sorbus, Heteromeles, Cratægus, and Amelanchier); leaves simple or pinnately compound, alternate (opposite in Lyonothamnus), with stipules, deciduous or persistent. XXIII. Leguminosæ (p. 585). Flowers perfect, regular or irregular; fruit a legume; leaves compound, or simple (Dalea), alternate, with stipules, deciduous or persistent. XXIV. Zygophyllaceæ (p. 630). Flowers perfect; calyx 5-lobed; petals 5; fruit capsular, becoming fleshy; leaves opposite, pinnate, with stipules, persistent. XXV. Malpigiaceæ (p. 631). Flowers usually perfect rarely dimorphous; calyx 5-lobed; petals 5, unguiculate; fruit a drupe or samara; leaves opposite, simple, entire, persistent; often with stipules. XXVI. Rutaceæ (p. 633). Flowers unisexual or perfect; fruit a capsule (Xanthoxylum), a samara (Ptelea), of indehiscent winged 1-seeded carpels (Helietta), or a drupe (Amyris); leaves alternate or opposite, compound, glandular-punctate, without stipules, persistent or rarely deciduous (0 in Canotia). XXVII. Simaroubaceæ (p. 641). Flowers diœcious, calyx 5-lobed; petals 5; fruit drupaceous (Simarouba), baccate (Picramnia), a samara (Alvaradoa); leaves alternate, equally pinnate, without stipules, persistent. XXVIII. Burseraceæ (p. 645). Flowers perfect; calyx 4 or 5-parted; petals 5; fruit a drupe; leaves alternate, compound, without stipules, deciduous. XXIX. Meliaceæ (p. 648). Flowers perfect; calyx 5-lobed; petals 5; fruit a 5-celled dehiscent capsule; leaves alternate, equally pinnate, without stipules, persistent. XXX. Euphorbiaceæ (p. 649). Flowers perfect; calyx 4—6-parted (Drypetes), 3-lobed (Hippomane), or 0 (Gymnanthes); petals 0; fruit a drupe (Drypetes and Hippomane), or a 3-lobed capsule (Gymnanthes). XXXI. Anacardiaceæ (p. 655). Flowers usually unisexual, diœcious or polygamo-diœcious (Pistacia without a calyx, and without a corolla in the North American species); fruit a dry drupe; leaves simple or compound, alternate, without stipules, deciduous (persistent in Pistacia and in one species of Rhus). XXXII. Cyrillaceæ (p. 665). Flowers perfect; calyx 5—8-lobed; petals 5—8; fruit an indehiscent capsule; leaves alternate, without stipules, persistent (more or less deciduous in Cyrilla). XXXIII. Aquifoliaceæ (p. 668). Flowers polygamo-diœcious; calyx 4 or 5-lobed; petals 5; fruit a drupe, with 4—8 1-seeded nutlets; leaves alternate, simple, with stipules, persistent or deciduous. XXXIV. Celastraceæ (p. 674). Flowers perfect, polygamous or diœcious; calyx 4 or 5-lobed; petals 4 or 5; fruit a drupe, or a capsule (Evonymus); leaves simple, opposite or alternate, with or without stipules, persistent (deciduous in Evonymus). XXXV. Aceraceæ (p. 681). Flowers diœcious or monœciously polygamous; calyx usually 5-parted; petals usually 5, or 0; fruit of 2 long-winged samara joined at the base; leaves opposite, simple or rarely pinnate, without or rarely with stipules, deciduous. XXXVI. Hippocastanaceæ (p. 702). Flowers perfect, irregular; calyx 5-lobed; petals 4 or 5, unequal; fruit a 3-celled 3-valved capsule; leaves opposite, digitately compound, long-petiolate, without stipules, deciduous. XXXVII. Sapindaceæ (p. 711). Flowers polygamous; calyx 4 or 5-lobed; corolla of 4 or 5 petals; fruit a berry (Sapindus and Exothea), a drupe (Hypelate), or a 3-valved capsule (Ungnadia); leaves alternate, compound, without stipules, persistent, or deciduous (Ungnadia). XXXVIII. Rhamnaceæ (p. 718). Flowers usually perfect; calyx 4 or 5-lobed; petals 4 or 5 (0 in Reynosia, Condalia, and Krugiodendron); fruit drupaceous; leaves simple, alternate (mostly opposite in Reynosia and Krugiodendron), with stipules, persistent (deciduous in some species of Rhamnus). XXXIX. Tiliaceæ (p. 732). Flowers perfect; sepals and petals 5; fruit a nut-like berry; leaves simple, alternate, mostly oblique at base, with stipules, deciduous. XL. Sterculiaceæ (p. 749). Flowers perfect; calyx 5-lobed; petals 0; fruit a 4 or 5-valved dehiscent capsule; leaves simple, alternate, with stipules, persistent. XLI. Theaceæ (p. 750). Flowers perfect; sepals and petals 5; fruit a 5-celled woody dehiscent capsule, loculicidally dehiscent; leaves simple, alternate, without stipules, persistent or deciduous. XLII. Canellaceæ (

tag="{http://www.w3.org/1999/xhtml}a">p. 753). Flowers perfect; sepals 3; petals 5; filaments united into a tube; fruit a berry; leaves simple, alternate, without stipules, persistent. XLIII. Kœberliniaceæ (p. 754). Flowers perfect; sepals and petals 4, minute; leaves bract-like, alternate, without stipules, caducous. XLIV. Caricaceæ (p. 755). Flowers unisexual or perfect; calyx 5-lobed; petals 5; fruit baccate; leaves palmately lobed or digitate, alternate, without stipules, persistent.

B. Ovary inferior (partly inferior in Rhizophora).

XLV. Cactaceæ (p. 757). Flowers perfect; petals and sepals numerous; fruit a berry; leaves usually wanting. XLVI. Rhizophoraceæ (p. 763). Flowers perfect; calyx 4-parted; petals 4; ovary partly inferior; fruit a 1-celled 1-seeded berry perforated at apex by the germinating embryo; leaves simple, opposite, entire, with stipules, persistent. XLVII. Combretaceæ (p. 764). Flowers perfect or polygamous; calyx 5-lobed; petals 5 (0 in Conocarpus); fruit drupaceous; leaves simple, alternate or opposite, without stipules, persistent. XLVIII. Myrtaceæ (p. 768). Flowers perfect; calyx usually 4-lobed, or reduced to a single body forming a deciduous lid to the flower (Chytraculia); petals usually 4 (0 in Chytraculia); fruit a berry; leaves simple, opposite, pellucid-punctate, without stipules, persistent. XLIX. Melastomaceæ (p. 776). Flowers perfect; calyx and corolla 4 or 5-lobed; stamens as many or twice as many as the lobes of the corolla; fruit capsular or baccate, inclosed in the tube of the calyx; leaves opposite, rarely verticillate, 3—9-nerved, without stipules. L. Araliaceæ (p. 777). Flowers perfect or polygamous; sepals and petals usually 5; fruit a drupe; leaves twice pinnate, alternate, with stipules, deciduous. LI. Nyssaceæ (p. 779). Flowers diœcious, polygamous, diœcious or perfect; calyx 5-toothed or lobed; petals 5 or more, imbricate in the bud, or 0; stamens as many or twice as many as the petals; fruit drupaceous (Nyssa), usually 1-celled and 1-seeded; leaves alternate, deciduous, without stipules. LII. Cornaceæ (p. 784). Flowers perfect or polygamo-diœcious; calyx 4 or 5-toothed; petals 4 or 5; fruit a fleshy drupe; leaves simple, opposite (alternate in one species of Cornus), without stipules, deciduous.

Section 2. Gamopetalæ. Corolla of united petals (divided in Elliottia in Ericaceæ, 0 in some species of Fraxinus in Oleaceæ).

A. Ovary superior (inferior in Vaccinium in Ericaceæ, partly inferior in Symplocaceæ and Styracaceæ).

LIII. Ericaceæ (p. 790). Flowers perfect; calyx and corolla 5-lobed (in Elliottia corolla of 4 petals); (ovary inferior in Vaccinium); fruit capsular, drupaceous or baccate; leaves simple, alternate, without stipules, persistent (deciduous in Elliottia and Oxydendrum). LIV. Theophrastaceæ (p. 804). Flowers perfect, with staminodia; sepals and petals 5; stamens 5; fruit a berry; leaves simple, opposite or alternate, entire, without stipules. LV. Myrsinaceæ (p. 805). Flowers perfect; calyx and corolla 5-lobed; stamens 5; fruit a drupe; leaves simple, alternate, entire, without stipules, persistent. LVI. Sapotaceæ (p. 808). Flowers perfect; calyx 5-lobed; corolla 5-lobed (6-lobed in Mimusops), often with as many or twice as many internal appendages borne on its throat; fruit a berry; leaves simple, alternate, without stipules, persistent (deciduous in some species of Bumelia). LVII. Ebenaceæ (p. 820). Flowers perfect, diœcious, or polygamous; calyx and corolla 4-lobed; fruit a 1 or several-seeded berry; leaves simple, alternate, entire, without stipules, deciduous. LVIII. Styraceæ (p. 824). Flowers perfect; calyx 4 or 5-toothed; corolla 4 or 5-lobed or divided nearly to the base, or rarely 6 or 7-lobed; ovary superior or partly superior; fruit a drupe; leaves simple, alternate, without stipules, deciduous; pubescence mostly scurfy or stellate. LIX. Symplocaceæ (p. 830). Flowers perfect; calyx and corolla 5-lobed; ovary inferior or partly inferior; fruit a drupe; leaves simple, alternate, without stipules, deciduous; pubescence simple. LX. Oleaceæ (p. 832). Flowers perfect or polygamo-diœcious; calyx 4-lobed (0 in some species of Fraxinus); corolla 2—6-parted (0 in some species of Fraxinus); fruit a winged samara (Fraxinus) or a fleshy drupe (Forestiera, Chionanthus and Osmanthus); leaves pinnate (Fraxinus) or simple, opposite, without stipules, deciduous (persistent in Osmanthus). LXI. Borraginaceæ (p. 858). Flowers perfect or polygamous; calyx and corolla 5-lobed; fruit a drupe; leaves simple, alternate, scabrous-pubescent, without stipules, persistent or tardily deciduous. LXII. Verbenaceæ (p. 864). Flowers perfect; calyx 5-lobed; corolla 4 or 5-lobed; fruit a drupe or a 1-seeded capsule; leaves simple, opposite, without stipules, persistent. LXIII. Solanaceæ (p. 867). Flowers perfect; calyx campanulate, usually 5-lobed; corolla usually 5-lobed; fruit baccate, surrounded at base by the enlarged calyx; leaves alternate, rarely opposite, without stipules. LXIV. Bignoniaceæ (p. 868). Flowers perfect; calyx bilabiate; corolla bilabiate, 5-lobed; fruit a woody capsule (Catalpa and Chilopsis) or a berry (Enallagma); leaves simple, opposite (sometimes alternate in Chilopsis), without stipules, deciduous (persistent in Enallagma).

B. Ovary inferior (partly superior in Sambucus in Caprifoliaceæ).

LXV. Rubiaceæ (p. 875). Flowers perfect; calyx and corolla 4 or 5-lobed; fruit a capsule (Exostema and Pinckneya), a drupe (Guettarda), or nut-like (Cephalanthus); leaves simple opposite, or in verticils of 3 (Cephalanthus), with stipules, persistent (deciduous in Pinckneya and Cephalanthus). LXVI. Caprifoliaceæ (p. 882). Flowers perfect; calyx and corolla 5-lobed; fruit a drupe; leaves unequally pinnate (Sambucus) or simple (Viburnum), opposite, without stipules, deciduous in North American species.

ANALYTICAL KEY
TO THE GENERA OF PLANTS INCLUDED IN THIS BOOK, BASED CHIEFLY ON THE CHARACTER OF THE LEAVES

I. Leaves parallel-veined, alternate, persistent, clustered at the end of the stem or branches. Monocotyledons. Stem simple; leaves stalked. Leaves fan-shaped. Leaf stalks unarmed. Rachis short; leaves usually silvery white below. Leaves 2°—4° in diameter (green below in No. 2), their segments undivided at apex. Thrinax (p. 96). Leaves 18′—24′ in diameter, their segments divided at apex. Coccothrinax (p. 100). Rachis elongated; leaves green below, their segments divided at apex. Sabal (p. 101). Leaf stalks armed with marginal teeth or spines. Leaf stalks furnished irregularly with broad thin large and small, straight or hooked spines confluent into a thin bright orange-colored cartilaginous margin; leaves longer than wide, divided nearly to the middle into segments parted at apex and separating on the margins into thin fibres. Washingtonia (p. 104). Leaf stalks furnished with stout or slender flattened teeth; leaves suborbicular, divided to the middle or nearly to the base into segments parted at apex; segments of the blade not separating on the margin into thin fibres. Acœlorraphe (p. 105). Leaves pinnate. Leaves 10°—12° in length, their pinnæ 2½°—3° long and often 1½° wide, deep green. Roystonea (p. 107). Leaves 5°—6° long, their pinnæ 18′ long and 1′ wide, dark yellow-green above, pale and glaucous below. Pseudophœnix (p. 109). Stem simple or branched; leaves sessile, lanceolate, long- and usually sharp-pointed at apex. Yucca (p. 110). II. Leaves 1-nerved, needle-shaped, linear or scale-like, persistent (deciduous in Larix and Taxodium). Gymnospermæ. 1. Leaves Persistent. a Leaves fascicled, needle-shaped, in 1—5-leafed clusters enclosed at base in a membranaceous sheath. Pinus (p. 2). aa Leaves scattered, usually linear. b Leaves linear, often obtuse or emarginate. Base of the leaves persistent on the branches. Leaves sessile, 4-sided, or flattened and stomatiferous above. Picea (p. 34). Leaves stalked, flattened and stomatiferous below, or angular, often appearing 2-ranked. Tsuga (p. 42). Base of the leaves not persistent on the branches; leaves often appearing 2-ranked. Leaves stalked, flattened, stomatiferous below; winter-buds pointed, not resinous. Pseudotsuga (p. 47). Leaves sessile, flattened and often grooved on the upper side, or quadrangular, rarely stomatiferous above, on upper fertile branches often crowded; winter-buds obtuse, resinous (except in No. 9). Abies (p. 50). bb Leaves linear-lanceolate, rigid, acuminate, spirally disposed, appearing 2-ranked by a twist in the petiole. Leaves abruptly contracted at base, long-pointed, with pale bands of stomata on the lower surface on each side of the midveins; fruit drupe-like. Torreya (p. 91).

Leaves gradually narrowed at base, short-pointed, paler, and without distinct bands of stomata on the lower surface; fruit berry-like. Taxus (p. 93). bbb Leaves ovate-lanceolate and scale-like, spreading in 2 ranks or linear on the same tree, acute, compressed, keeled on the back and closely appressed or spreading at apex. Sequoia (p. 61). aaa Leaves opposite or whorled, usually scale-like. Internodes distinctly longer than broad; branchlets flattened, of nearly equal color on both sides; leaves eglandular. Libocedrus (p. 65). Internodes about as long as broad, often pale below, usually glandular. Branchlets flattened. Branchlets in one plane, much flattened, 1/12′—⅙′ broad. Thuya (p. 67). Branchlets slightly flattened, 1/24′—1/16′ broad. Chamæcyparis (p. 75). Branchlets terete or 4-angled. Branchlets more or less in one plane; fruit a cone. Cupressus (p. 69). Branchlets not in one plane; fruit a berry (leaves needle-shaped, in whorls of 3 in No. 1). Juniperus (p. 78). 2. Leaves Deciduous. Leaves in many-leafed clusters on short lateral spurs. Larix (p. 31). Leaves spreading in 2 ranks. Taxodium (p. 63). III. Leaves netted-veined, rarely scale-like or wanting. Dicotyledons. A. LEAVES OPPOSITE. (B, see p. xix). 1. Leaves Simple. (2, see p. xviii). Leaves persistent. a Leaves with stipules. b Leaves entire or occasionally slightly crenate or serrate. c Leaves emarginate at apex, very short-stalked, 1½′—2′ long. Leaves obovate, gradually narrowed into the petiole. Gyminda (p. 678). Leaves oval to oblong, rounded or broad-cuneate (rarely alternate). Branchlets densely velutinous. Krugiodendron (p. 721). Branchlets slightly puberulous at first, soon glabrous. Reynosia (p. 720). cc Leaves not emarginate at apex. Leaves obtuse, rarely acutish or abruptly short-pointed. Leaves elliptic, 3½′—5′ long. Rhizophora (p. 763). Leaves obovate, usually rounded at apex, ¾′—2′ long. Byrsonima (p. 632). Leaves acute to acuminate. Leaves oblong-ovate to lanceolate; branchlets glabrous. Exostema (p. 877). Leaves broad-elliptic to oblong-elliptic; branchlets villose. Guettarda (p. 879). bb Leaves serrate (often pinnate). Lyonothamnus (p. 378). aa Leaves without stipules. Petioles biglandular; leaves obtuse or emarginate, 1½′—2½′ long. Laguncularia (p. 767). Petioles without glands. Leaves furnished below with small dark glands, slightly aromatic; petioles short. Leaves oblong to oblong-ovate and acuminate or elliptic and bluntly short-pointed. Calyptranthes (p. 769). Leaves ovate, obovate or elliptic. Eugenia (p. 770). Leaves without glands. Leaves green and glabrous below. Leaves obtuse or emarginate at apex (rarely alternate), 1′—1½′ long. Torrubia (p. 341). Leaves acute, acuminate, or sometimes rounded or emarginate, 3′—5′ long. Leaves distinctly veined. Citharexylon (p. 864). Leaves obscurely veined. Osmanthus (p. 856). Leaves hoary tomentulose or scurfy below. Leaves strongly 3-nerved, acuminate, densely scurfy below. Tetrazygia (p. 776). Leaves penniveined, rounded or acute at apex, hoary tomentulose below. Avicennia (p. 865). ** Leaves deciduous. a Leaves without lobes. b Leaves serrate. Winter-buds with several opposite outer scales. Leaves puberulous below, closely and finely serrate; axillary buds solitary. Evonymus (p. 675). Leaves glabrous below, remotely crenate-serrulate; axillary buds several, superposed. Forestiera (p. 853). Winter-buds enclosed in 2 large opposite scales. Viburnum (p. 886). bb Leaves entire. c Leaves without stipules. Leaves suborbicular or elliptic to oblong. Leaves rounded or acutish at apex, 1′—2′ long, occasionally 3-foliolate, glabrous; branchlets quadrangular. Fraxinus anomala (p. 837). Leaves acuminate or acute at apex, 3′—4′ long. Leaf-scars connected by a transverse line, with 3 bundle-traces; branchlets slender, appressed-pubescent. Cornus (p. 785). Leaf-scars not connected, with 1 bundle-trace; branchlets stout, villose, puberulous or glabrous. Chionanthus (p. 855). Leaves broad-ovate, cordate, acuminate, 5′—12′ long, on long petioles. Catalpa (p. 870). Leaves linear to linear-lanceolate, short-stalked or sessile (sometimes alternate). Chilopsis (p. 869). cc Leaves with persistent stipules, entire. Leaves oval or ovate; winter-buds resinous, the terminal up to ½′ in length. Pinckneya (p. 876). Leaves ovate to lanceolate; winter-buds minute. Cephalanthus (p. 878). aa Leaves palmately lobed. Acer (p. 681). 2. Leaves Compound. a Leaves persistent, with stipules. Leaves equally pinnate; leaflets entire. Guaiacum (p. 630). Leaves unequally pinnately parted into 3—8 linear-lanceolate segments (sometimes entire). Lyonothamnus (p. 378). Leaves trifoliate. Leaflets stalked. Amyris (p. 640). Leaflets sessile. Helietta (p. 637). aa Leaves deciduous. Leaves unequally pinnate or trifoliate. Leaflets crenate-serrate or entire, the veins arching within the margins; stipules wanting; winter-buds with several opposite scales. Fraxinus (p. 833). Leaflets sharply or incisely serrate, the primary veins extending to the teeth. Leaflets 3—7, incisely serrate; stipules present; winter-buds with 1 pair of obtuse outer scales. Acer Negundo (p. 699). Leaflets 5—9, sharply serrate; stipules present; winter-buds with many opposite acute scales; pith thick. Sambucus (p. 882). Leaves digitate, with 5—7, sharply serrate leaflets; terminal buds large. Æsculus (p. 702). B. LEAVES ALTERNATE. 1. Leaves Simple. (2, see p. xxiv). * Leaves persistent. (** see p. xxii). a Leaves deeply 3—5-lobed, ⅓′—½′ long, with linear lobes, hoary tomentose below. Cowania (p. 549). aa Leaves palmately lobed. Leaves stellate-pubescent, about 1½′ in

diameter, with stipules. Fremontia (p. 749). Leaves glabrous, 1°—2° in diameter, without stipules. Carica (p. 755). aaa Leaves not lobed or pinnately lobed. b Branches spinescent. Leaves clustered at the end of the branches, at least 2′—3′ long. Bucida (p. 765). Leaves fascicled on lateral branchlets, obtuse or emarginate, pale and glabrous beneath. Bumelia angustifolia (p. 816). Leaves scattered. Leaves generally obovate, mucronate, not more than ½′—1′ long, glabrous and green or brownish tomentulose beneath. Condalia (p. 719). Leaves elliptic-ovate to oblong, obtuse or emarginate, glabrous, 1—2 cm. long. Ximenia (p. 337). bb Branches not spinescent. c Leaves serrate, or lobed (in some species of Quercus). (cc, see p. xxii). d Juice watery. (dd, see p. xxii). e Stipules present. (ee, see p. xxii). f Primary veins extending straight to the teeth. Leaves and branchlets glabrous or pubescent to tomentose with fascicled hairs. Leaves fulvous-tomentose beneath, repand-dentate, 3′—5′ long. Lithocarpus (p. 236). Leaves glabrous or grayish to whitish tomentose beneath, entire, lobed or dentate. Quercus sp. 21—34 (p. 268). Leaves and branchlets coated with simpled silky or woolly hairs at least while young, not more than 2½′ long. Cercocarpus (p. 550). ff Primary veins arching and united within the margin. Leaves 3-nerved from the base. Ceanothus (p. 726). Leaves not 3-nerved. Leaves acute. Leaves sinuately dentate, with few spiny teeth (rarely entire), glabrous. Ilex opaca (p. 669). Leaves serrate. Leaves tomentose below; branchlets tomentose. Leaves narrow-lanceolate, glabrous and smooth above. Vauquelinia (p. 377). Leaves ovate, cordate, scabrate above. Trema (p. 327). Leaves glabrous below. Heteromeles (p. 392). Leaves entire, very rarely toothed. Leaves elliptic, glabrous. Prunus caroliniana (p. 579). Leaves oblanceolate, pubescent beneath when young. Ilex Cassine (p. 670). Leaves obtuse, sometimes mucronate. Leaves spinose-serrate, glabrous. Leaves broad-ovate to suborbicular or elliptic; branchlets dark red-brown, spinescent. Rhamnus crocea (p. 723). Leaves ovate to ovate-lanceolate; branchlets yellow or orange-colored, not spinescent. Prunus ilicifolia (p. 581). Leaves crenate (often entire), oval to oblong. Ilex vomitoria (p. 671). ee Stipules wanting. Leaves resinous-dotted, aromatic, 1½′—4′ long. Myrica (p. 163). Leaves not resinous-dotted, crenately serrate, 4′—6′ long. Leaves dark green, glabrous below. Gordonia Lasianthus (p. 751). Leaves yellowish green, pubescent below, sometimes nearly entire. Symplocos (p. 831). dd Juice milky. Petioles 2½′—4′ long; leaves broad-ovate. Hippomane (p. 652). Petioles about ¼′ long; leaves elliptic to oblong-lanceolate. Gymnanthes (p. 654). cc Leaves entire (rarely sparingly toothed on vigorous branchlets). d Stipules present. e Stipules connate, at least at first. Stipules persistent, forming a sheath surrounding the branch above the node; leaves obtuse. Coccolobis (p. 338). Stipules deciduous, enveloping the unfolded leaf. Leaves ferrugineous-tomentose beneath. Magnolia grandiflora (p. 345). Leaves glabrous beneath, with milky juice. Ficus (p. 333). ee Stipules free. f Juice milky; leaves oval to oblong, 3′—5′ long. Drypetes (p. 650). ff Juice watery. g Leaves obtuse or emarginate at apex. Leaves with ferrugineous scales beneath, their petioles slender. Capparis (p. 365). Leaves without ferrugineous scales. Leaves soft-pubescent on both sides. Colubrina cubensis (p. 730). Leaves glabrous at least at maturity. Leaves rarely 2′—3′ long, standing on the branch at acute angles. Chrysobalanus (p. 583). Leaves rarely more than 1′ long, spreading (sometimes 3-nerved). Ceanothus spinosos (p. 728). gg Leaves acute or acutish. Petioles with 2 glands. Conocarpus (p. 766). Petioles without glands. Leaves and branchlets more or less pubescent, at least while young. Leaves fascicled except on vigorous branchlets. Cercocarpus (p. 550). Leaves not fascicled. Winter-buds minute, with few pointed scales. Leaves rounded or nearly rounded at base. Colubrina sp. 1, 3 (p. 729). Leaves broad-cuneate at base. Ilex Cassine (p. 670). Winter-buds conspicuous, with numerous scales. Leaves usually lanceolate, entire, covered below with yellow scales. Castanopsis (p. 234). Leaves oblong or oblong-obovate, repand-dentate, fibrous tomentose below. Lithocarpus (p. 236). Leaves and branchlets glabrous. Leaf-scar with 1 bundle-trace. Ilex Krugiana (p. 672). Leaf-scar with 3 bundle-traces. Cherry Laurels. Prunus sp. 19—22 (p. 579). dd Stipules wanting. e Leaves aromatic when bruised. Leaves resinous-dotted. Myrica (p. 163). Leaves not resinous-dotted. Leaves obtuse, obovate, glabrous. Canella (p. 753). Leaves acute. Leaves mostly rounded at the narrowed base, ovate to oblong, acute, glabrous. Anona (p. 354). Leaves more or less cuneate at base, elliptic to lanceolate, usually acuminate. Leaves abruptly long-acuminate, glabrous, the margin undulate; branchlets red-brown. Misanteca (p. 364). Leaves gradually acuminate or nearly acute. Leaves strongly reticulate beneath. Branchlets glabrous, light grayish brown; leaves glabrous, light green beneath. Ocotea (p. 359). Branchlets pubescent while young, greenish or yellowish; leaves pale beneath, pubescent while young. Umbellularia (p. 360). Leaves not or slightly reticulate, glaucous, glabrous or pubescent beneath. Persea (p. 356). ee Leaves not aromatic. f Leaves acute or acutish. Leaves obovate, gradually narrowed into short petioles. Leaves 2′—2½′ long. Schæfferia (p. 679). Leaves at least 6′—8′ long. Enallagma

(p. 873). Leaves elliptic to oblong or ovate. Leaves rough or pubescent above, pubescent below, subcordate to cuneate at base. Leaves stellate-pubescent. Solanum (p. 867). Leaves scabrous above. Petiole ⅛′—¼′ long; leaves oval or oblong, 1¼′—4′ long. Ehretia (p. 862). Petiole 1′—1½′ long; leaves ovate to oblong-ovate, 3′—7′ long. Cordia (p. 858). Leaves smooth above. Winter-buds scaly. Leaves covered below with ferrugineous or pale scales, 1′—3′ long. Lyonia (p. 797). Leaves glabrous or nearly so below. Leaves ovate-lanceolate or obovate-lanceolate, 4′—12′ long, usually clustered at end of branchlet, veinlets below obscure. Rhododendron (p. 792). Leaves elliptic or oval to oblong or lanceolate. Leaves light yellowish green below and without distinctly visible veins or veinlets, entire, 3′—4′ long. Kalmia (p. 794). Leaves pale below and more or less distinctly reticulate, occasionally serrate or denticulate, 1′—5′ long; bark of branches red. Arbutus (p. 799). Winter-buds naked. Leaves pubescent below when unfolding. Mature leaves nearly glabrous below. Leaves oblong-lanceolate to narrow-obovate. Dipholis (p. 810). Leaves oval. Sideroxylum (p. 809). Mature leaves covered below with brilliant copper-colored pubescence. Leaves glabrous below. Chrysophyllum (p. 817). Leaves marked by minute black dots, ovate to oblong-lanceolate. Ardisia (p. 806). Leaves lepidote, oblong-obovate. Rapanea (p. 807). ff Leaves obtuse or emarginate at apex. g Leaves rounded or cordate at base, emarginate, their petioles slender. Leaves reniform to broad-ovate, cordate; juice watery. Cercis (p. 603). Leaves elliptic to oblong, rounded at base; juice milky or viscid. Leaves emarginate; petioles slender, rufous-tomentulose. Mimusops (p. 819). Leaves obtuse at apex; petioles stout, grayish-tomentulose or glabrous. Rhus integrifolia (p. 664). gg Leaves cuneate at base. Petioles slender, ½′ long. Beureria (p. 861). Petioles short and stout. Leaves coriaceous, with thick revolute margins (sometimes opposite). Jacquinia (p. 804). Leaves subcoriaceous, slightly revolute. Leaves reticulate-veined beneath. Leaves oval to obovate or oblong-oval, more or less pubescent while young. Vaccinium (p. 802). Leaves oblong to oblong-obovate, glabrous. Cyrilla (p. 666). Leaves obscurely veined beneath, glabrous. Leaves oblong-lanceolate, narrowed toward the emarginate apex, decurrent nearly to base of petiole. Cliftonia (p. 667). Leaves rounded at apex, distinctly petioled. Maytenus (p. 676). ** Leaves deciduous. † Leaves conspicuous. (††, see p. xxiv.)