Part 1

PRINCIPAL TREE REGIONS OF NORTH AMERICA

A North Eastern B North Western AB North Eastern & North Western C South Eastern D Tropical Florida E Texas-Mexican Boundary F Rocky Mountains G Oregon & California H New Mexico & Arizona Mexican Boundary

MANUAL OF THE TREES OF NORTH AMERICA (EXCLUSIVE OF MEXICO)

BY CHARLES SPRAGUE SARGENT _Director of the Arnold Arboretum of Harvard University_ _Author of The Silva of North America_

_WITH SEVEN HUNDRED AND EIGHTY-THREE ILLUSTRATIONS FROM DRAWINGS BY_ CHARLES EDWARD FAXON _AND_ MARY W. GILL

_Second Edition_

BOSTON AND NEW YORK HOUGHTON MIFFLIN COMPANY _The Riverside Press Cambridge_ 1922

COPYRIGHT, 1905 AND 1927, BY CHARLES SPRAGUE SARGENT ALL RIGHTS RESERVED PRINTED IN THE UNITED STATES OF AMERICA

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.

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 (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_).