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Curator, New York Botanical Garden


Published by the Author


Copyright, 1917 Per Axel Rydbehg

Press of


Lancaster. Pa.



After more than twenty-five years of study of the flora of the Rocky Mountain region, and seventeen years after the first description was drawn for the book, this manual is now presented to the public. Its history, pur- pose and scope are given in the introduction, with certain necessary explana- tions regarding the general features of the book.

Thanks are due to the custodians of many herbaria for the privilege of studying collections and types, and for the loan of specimens; these herbaria are enumerated in my introduction. The author wishes to thank all his associates at the New York Botanical Garden, especially Dr. N. L. Britton, Director-in-Chief, for encouragement and help in his work; Dr. J. K. Small, for help in critical cases and in certain groups, as for instance Polygonaceae and Saxifragaceae, and in the original draft of the key to the families; and Dr. J. H. Barnhart, for help in questions of nomenclature and literature. In drawing the generic descriptions, the author has frequently consulted Dr. Small's Flora of the Southeastern United States. Dr. Barnhart has contributed also the list of authors, including their full names and years of births and deaths wherever it has been possible.

Thanks are also due to Mr. K. K. Mackenzie, who contributed the manu- script of Carex; to Professor E. Brainerd, who prepared that of Viola; and to Mr. W. W. Eggleston, who revised that of Crataegus.

As most manuals of phaenerogamic botany also contain the ferns and their allies, an account of the fern-worts by Miss Margaret Slosson has been appended. The families Isoetaceae, Equisetaceae and Selaginellaceae were left by her until the last. She did some preliminary work on Selagin- ella, but before the work was finished she left the New York Botanical Gar- den temporarily, and the completion of the fern worts fell upon the author, who feels that the treatment of the three families is not adequate, as the manuscript was prepared hurriedly while the book was going through the press.

The author is indebted especially to the following botanists, who have kindly corrected the statements of the ranges of all of the species and fur- nished additions to the list of species known to occur in their respective states and provinces: Mr. J. M. Macoun, western Canadian provinces; Professor J. E. Kirkwood, Montana; Mr. J Francis Macbride, Idaho; Pro- fessor A. 0. Garrett, Utah; and Mr. George E. Osterhout, Colorado. Thanks are also due to the following persons who have gratuitously helped in read- ing the proofs: Professor A. 0. Garrett, Mr. G. E. Osterhout, Miss K. D. Kimball, and Mr. A. E. Urban, now manager of The Hershey Pre-ss, who kindly continued proofreading even after he left his old concern. The help of Mr. Urban, who is an amateur botanist as well, has been especially valu- able.

P. A. Rydberg. The New York Botanical Garden, November, 1917.



Introduction v

Tables: Abbreviations, Signs and Measurements xii

Descriptive Flora

Spermatophyta : Key to the Families 1

Gyimnospermae 11

Angiospermae: Monocotyledones 20

Dicotyledones 185

Pteridophyta 1038


Summary 1057

New Genera and Species and New Combinations 1060

Abbreviations of the Names of Authors 1070

Glossary 1078

Index 1088


Preliminary Work

In 1890, the author spent a month in western Nebraska. In the following Slimmer he was commissioned to coUect in the same region for the United States Department of Agriculture, and in 1892 in the Black Hills of South Dakota. A report on the last was published in 1896, in the Contributions from the Na- tional Herbarium, volume 3. These trips first introduced him to the flora of a part of the region covered by this manual. Since then he has done field work, partly for the United States Department of Agriculture and partly for the New York Botanical Garden, in Montana, Yellowstone National Park, Colorado and Utah, and has made shorter stops in eastern Idaho and southern Wyoming. In aU, he has spent eleven siunmers in the Rocky Mountain region. In this field work he was associated with or assisted by the following men: C. L. Shear, Ernst A. Bessey, A. O. Garrett, J. H. Flodman, F. K. Vreeland, and E. C. Carl- ton, to whom thanks are due.

After collecting for two summers and a half in Montana and the Yellowstone National Park, the author pubhshed in 1900, a Catalogue of the Flora of Montana and the Yeli,owstone National Park.* In preparing this, he studied the extensive collections made by Frank Tweedy of the United States Geological Survey, as well as that of W. M. Canby, and one made for the World's Fair in Chicago, 1893.

In 1901 the author was requested to determine the collection accumulated at the Agricultural College at Fort CoUins, Colorado, made by James Cassidy, C. S. Crandall, J. H. Cowan, and their assistants and students, and finally to pre- pare the results for publication. The Flora of Colorado! appeared in 1906. At this time the author had spent a summer and a half collecting in Colorado and the New York Botanical Garden had secured an almost complete set of C. F. Baker's, and Baker, Earle and Tracy's collections in that state. Together with the older collections preserved in the herbarium of Columbia University the material mentioned above made possible an almost complete catalogue of the Colorado flora.

The preparation of the manual has taken a longer time than expected, as only a small part of the author's time could be used for the work. During the time (1900-1916) the work has been progressing, the author has published a series of 29 papers imder the title "Studies on the Rocky Mountain Flora," in which numerous new species have been published. The pubUcation of a second edition of Coulter's Manual in the form of "A New Manual of Botany of the Central Rocky Mountains," by J. M. Coulter and Aven Nelson, in 1909, made the appearance of the contemplated flora less urgent, as the need was partly supphed, and the issuing of the manual was delayed.

Material Used in the Work

The main part of the work has been done in the herbarium of the New York Botanical Garden, where also the collections of Columbia University (including the Torrej^ and Morong herbaria) are deposited. These herbaria contain numer- ous types or duplicates of types of species described by Torrey, Torrey and Gray, Nuttall, Hooker, and Richardson, as well as the first sets of several collections and duphcate sets of many others.

The author has visited the United States National Herbarium five times, for weeks at a time, and has often had specimens as loans for study. He has gone through it quite thoroughly, except the family Cichoriaceae. The studies

* Mem. N. Y. Bot. Gard. vol. 1.

t Agr. Exp. Sta. Colo. Agr. CoU. Bull. no. lOO.


there included investigations of the types of species described by Vasey, Coville, Rose, Hitchcock, Scribner, Standley, and others; Dr. E. L. Greene's herbarium was deposited there at that time. The author has also made four similar visits to the Gray Herbarium, mainly to study types, especially those of plants de- scribed by Gray, Watson, Robinson, Fernald, Greenman, and others; three short visits to the Philadelphia Academy to study the types of Pursh and Nuttall; one to the Field Museum, Chicago; one to the Missouri Botanical Garden; one to the Geological Survey of Canada; and a day's stop at the Rocky Mountain Herbarium at Laramie. In 1901 he spent more than a week at the Royal Gar- dens, Kew, where he studied all the types of the plants described in Hooker's Flora Boreali-Ajiericana, and made a visit to the British Museum, which con- tains many of Nuttall's types. The herbarium of the College of Pharmacy of New York City has often been consulted and specimens borrowed therefrom. In addition, the following herbaria have passed through his hands for study and determination: Herbarium of the Agricultural College of Colorado; Herbarium of the Agricultural College of Montana (before 1900) ; Frank Tweedy's herbarium, now at Yale University; and the herbaria of F. D. Kelsey and F. E. Leonard, now at Oberlin College. The only important collections from the Rocky Mountains not studied are that of M. E. Jones and that of the University of Wyoming; many duplicates from these have been available, however. The author has also corresponded for years with Mr. Osterhout, Prof. Garrett, Prof. Cockerell, Mr. Macoun, and many others.

Area Covered by the Manual

When the manual was first contemplated the author estimated that it would comprise the description of about 4000 species; this estimate might have proved correct if the work had been limited to the Rocky Mountains themselves. His knowledge of the vegetation of the plains east of them, a flora not adequately treated in any manual, induced the author to include that also. As he has been interested in "the flora of the northern Rockies, perhaps more than any one else in the United States, the Geological Survey of Canada has for years sent the first set of its exchanges from the Rocky Mountain region to the New York Botanical Garden; it was desirable, therefore, to include the flora of this part of Canada in the manual, and perhaps 200 northern species have been added. The parts of Utah west and south of Wahsatch Mountains, as well as western Idaho, have not been included in any of the floras of the Rocky Mountain region. As many collections have been made in the part of Utah mentioned, by Edward Palmer, C. C. Parry, A. L. Siler, Mrs. Almon H. Thompson, L. F. Ward, and others, and especially lay M. E. Jones, the whole of the states of Utah and Idaho was in- cluded and at least 500 or 600 species thus added. The total number of species, in the meantime, has grown to nearly 5900.

The area covered by this flora thus includes the entire states of Colorado, Utah, Wyoming, Idaho, and Montana, and extends eastward to long. 102° W. in Nebraska, South Dakota and North Dakota; it also includes the Canadian i>rov- inces of Saskatchewan and Alberta, south of lat. 55° N. (the old boundary of the territories of the same name*), and the Kootenay Districts of British Columbia. The Rockies extend for some distance south into New Mexico, but no attempt has been made to cover any part of that state; as far as the truly mountain flora is concerned, however, it is practically covered.

As the number of known species within the area has increased, the author has been obhged to shorten the descriptions in order to make the book of a con- venient size; cutting dowm original descriptions one-fourth or more, and usually avoiding repetition of characters given in the keys. The resulting brevity will naturally detract from the value of the work, but otherwise the book would have become too bulky to be convenient, especially in the field. The descriptions are nearly all redrawn from actual specimens. The original types or duplicates of the types have been consulted wherever possible, and rarely have the original descriptions been merely copied or condensed.

* The present boiinrlary i.s lat. 60°, but the region between lat. 55° and G0°, is botan- ically practically unknown. *


Nomenclature and Limitation of Genera and Species

The nomenclature used agrees, as far as possible, with the so-called American Code, used at the United States National Herbarium and Department of Agri- culture, the New York Botanical Garden, and many of the universities and botanical institutions of this country. It differs from the International Code, followed by many institutions, principally in the following two features: it allows few exceptions from the rule that the oldest generic and specific name (after Linnaeus' Species Plantarum of 1753) should be used, and provides that, if a Latin name has been used for one plant, it can never be used for another. The nomenclature used in this manual differs somewhat on this account from that used by other writers on the flora of the region or a part thereof. Another im- portant difference is due to the fact that the author beheves that in many cases unnatural groups of species of diverse habit and structure should not be retained as genera just because our predecessors have regarded them as such. In other words, a genus should be divided into several, if it can be split up into smaller and more natural ones. Such divided genera are, for instance, the old large genera Astragalus, Oenothera, and Aster. On the other hand, the fully as large genera Carex, Eriogonum, and Senecio have been kept intact, as no natural divi- sion could be found.

For those who disagree with the author in the matters of nomenclature and limitation of genera and species, there will be very little difficulty in finding the scientific name to which they are accustomed, as synonyms have been freely cited, in fact as far as deemed necessary. The synonymy, of course, is by no means complete ; only such is included as has been in use for the plant recently, or is necessary for the explanation of the accepted name, or represents supposed new species, which the author regards as indistinguishable from the one described. In the cases where a synonym is preceded by a "(?)" this means that the author has not seen the tj-pe of the synonym, but from the description supposes that it represents the same species as the one accepted.

A few of my friends have suggested that the place of publication of each name should also be given; while this would have increased the utility of the book, it would have added perhaps 150 pages. This manual will be useful to three classes: the amateur botanists, the students in high schools and colleges, and the professional botanists. The first two classes, as a rule, do not care for the full citation, and most of the professional botanists have access to the "Kew Index" and the "Card Catalogue," or other reference books. The omission of the place of publication will work hardships, therefore, to only a few.

Pronunciation and Accentuation In most of the schools of this country the so-called Roman pronunciation is used in reading Latin, but exceedingly few botanists pronounce the Latin names in accordance with it. They are supposed to pronounce it according to the so- called English method, but the author has not found two persons who do it alike. He frankly admits that he does not know how to pronounce the names according to the latter method. According to the Roman method, as he was taught it, the vowels are pronounced nearly as follows:

short as in hat " " " met

" " " not " " " put

The consonants he learned to pronounce as they are in English, except that c and g are hard as in cat or go, even before e, i, and y; j as consonant y, z Bats, and ch and j)h in Greek words as k and /.

Most of the mispronunciations, whether the English, Continental, or Roman pronunciation is used, are due to ignorance of the accent. On the proper ac- centuation the author wishes to say more,* as the specific names in this volume

* The explanations given in this discussion may not agree •\vith most Latin grammars in English, but the author thinks that this is because the English grammarians consciously or miconsciously interpret constructions in Latin according to the models of the highly individuaUzed English language.

a e i

long as in father " " " there " " " machine

o u

" " " no " " " rule


do not have the accent indicated. Clements gives the following rule for accents: "In words of two syllables or more the accent is on the penult [next to the last syllable], when it is long; when the penult is short, the antepenult [third syllable from the end] is accented." This is correct if rightly understood. Long syllables are of two kinds, however; one with vowel length, the other with consonant length, that is, when it ends in one or more consonant sounds. Unfortunately, in a syllable with consonant length the vowel is usually called short, not only in Elnglish, but in most modern languages. In many Latin lexicons the vowel in such a syllable is marked as long (wrong according to modern notions), in a few as short; others are noncommittal. In fact, the syllable is long (as shown in verse) although the vowel is short. There are three kinds of syllables, tM^o end- ing in vowels, and one in a consonant. If there are one or more consonants between two vowels, one of these is always counted to the second syllable and the rest to the first, except that ch, ph, and th are regarded as one letter and a mute followed by r is carried to the second syllable {hy-dra, as-tra).

The grave accent (d) is here used to denote a long vowel* and the acute (d) a short vowel syllable or a syllable with consonant length. The penult has the accent when it ends in a consonant, but if it ends in a vowel it has the accent only if this vowel is long. In hy-dro-phjl-lum (water-leaf) the penult ends in a consonant and hence has the accent, and the vowel is marked short, as the syllable has consonant length; in hy-dro-phi-la (water-lover) the penult ends in a vowel and this is short; the accent is removed to the antepenult and, as the connecting vowels i (in Latin) or o (in Greek) in compound words are short, the antepenult has a short accent. Greek words follow practically the same rules, but un- fortimately they do not always have the same quantity as the corresponding Latin words. For instance, in Latin the y in stylus (in classical Latin better stilus) is short, while in (xrvko^ the v is long. In brevistylis (Latin) the accent is on the antepenult, while in brachystylis (Greek) it is on the penult. A person must not be influenced by the English pronunciation of words similar to or derived from the Latin or Greek scientific terms, as it is very often corrupted. The words Spermatophyta, Pteriddphyta, etc., have the accent on the antepenult and short o and y, while the English Spcrmdtophyte and Ptendophyte have the accent on the antepenult with a long y in the last syllable. Just the reverse we find in the Greek and Latin Anemone and the English Anemone.

As stated before, when the penult ends in a consonant, i. e., when the vowel is followed bj^ two consonants or more, or a double consonant, it always has the accent and this is short. If, however, the vowel is followed by one or no con- sonant, one has to find out whether it is long or short. To determine this one has very often to go to the lexicon. Most of the specific names are Latin or Greek adjective, some are nouns in the genitive case, and a few are old generic names or nouns of barbaric origin. For the last two categories no rules can be given, but the following hints may help in pronouncing the adjectives and geni- tives :

The penult is long, as a rule, in the following adjective endings and hence takes the long accent: -d/is,t -anus, -dm, -dtus, -enus, -elus, -i7iu^,t -ilus, -ivus, aides, -ovus, -osus, -unus, -iines, -iirus, -iisus, -^tus. In classical Latin there were verj' few compound adjectives, but in botanical Latin they are used freely. A few in which the last term has a long vowel in the penult and hence accented, may be mentioned: -fiisus, -glumis, -physus, -florus.

The penult has usually a short vowel in the following adjective endings, and hence the accent is removed to the antepenult: -acus, -eus, -eris, -crus, -eger

* Tills must not be confused with the so-called long EngUsh a, for in English nearly all the sotinds of a (except the short a as in "hat") are long. The a in "hall" is long in English, though not the so-called long sound. In Latin, a word with such a spelling would have consonant length and be denoted with the short accent. In EngUsh the a in the names Hall and Haller are pronounced differently, as it is in mall and mallet, but in Latin the a is pronounced the same in Hdllii and Hdlleri.

t Only the mascuhnc form is given here, the feminine and neuter forms follow the same rule; -alls and -anus stand for -alis, -alis, -ale, and -anus, -ana, -aniim, etc.

t Short in serotinus, (inssipinus, cannabinus, and others. On the other hand salicinus and cyperinus arc usually indicated as long. The classical form of these words were, how- ever, salignus and cyprinus.


(-egra, -egrum), -icus, -ichus, -iilis, -idus, -His, -ilus, -imus, -tor, -ius, -uus, -yus. The compound words ending in the following syllables have also a short vowel in the penult: -cladus, -cola, -color, -fera, -ferum, -gcra, -gerum, -gijnus, -fidus, -fdus, -philus, -lepis, -olens, -pilis, -podus, -stomus, -tomus, -virens, -phylum. If the short connecting vowels i (in Latin) and o (in Greek) appear in the penult, they are not accented; when they appear in the antepenult in words with short penult they receive the short accent: drmiger, armigera, sjAnifer, spinifera. Of course, in adjective endings in which the penult has consonant length, this is accented and the vowel is short: -ensis, -ellus, -illus, -formis, -eslus, -uster, -ester, -essus. The same rule applies to compound words enging in -cdrpus, -roslris, -phyllu^.

Bj' following the hints given above, any one can accent correctly eighty per cent, of the specific names in this flora. A few words may be said concerning the genitives of personal names and the same remarks apply to generic names dedicated to persons. The usual method of Latinizing a personal name is to add ius (genitive -it) or, in case of a generic name dedicated to a person, -ia, to it if it ends in a consonant (except r), and -us (-i) and -a if the name ends in a vowel or r. If the noun ends in -er, as Palmer, it is better to regard this as the proper Latin form with Palmer-i in the genitive. As the i in the penult of -ii and -ia always is short, the accent in such words will always be on the antepenult. Harder to determine is the place of accent if the genitive ends in a single -i or the generic name in merely -a, as it depends upon whether the penult is long or short. Many botanists pronounce the names derived from persons as they would the family name itself, with the Latin ending added, as Jdmes-i-a and Jdmes-i-i, named for James; while the Latin usage would require Ja-me-si-a and Ja-me-si-i. In Latin all syllables are pronounced and the accent can never be further from the end than in the antej^enult. It has been a custom to regard the vowel in the antepenult of the endings -esii, -onii, -inii, -unii, -elii, etc., and in the penult of -onis, -oni as long. Many include the ending -eri. This would be perhaps defendable in the case of Berlandieri, Plumieri, where the ending er has the accent in French and in plant names dedicated to some German and Scandinavian persons who write their name with an accent on the last syllable, but the author does not think it correct in Pdlmeri, Boreri, Breweri, Wdrneri, where the English name has a short er and the words in er following the second declen- sion in Latin as a rule had short e in the genitive or dropped it altogether. The author thinks that the four names just mentioned should have the accent on the first syllable.

The generic names are much harder to treat. They are old Latin or Greek nouns, or vernacular names, with or without Latin endings, or modified personal names, or compound words (mostly Greek) manufactured according to the whims of the authors. The author saw no other way but to indicate their proper ac- cent in each case as far as they could be ascertained.

Names of Authors

The generic and specific names are followed by the names of their authors, usually abbreviated; the abbreviations are explained on pages 1070-8. If an author's name is placed in parenthesis after a generic name, it means that he published it before 1753 and that it was accepted after that date by the author following the parenthesis (usually Linnaeus). After the specific name, an author's name in parenthesis signifies that he originally proposed it, either in another genus or else only as a subspecies, variety, or form, and the author follow- ing the parenthesis was the first one to make the accepted combination.

Common Names

The common names are given in most cases after the Latin generic name. A common name has been inserted after the description of a species only where it seems to apply exclusively or principally to that species. In the Rocky Moun- tain region the common names apply usually to all species of the genus rather than to a particular one. No attempt has been made to manufacture a " common name" where there is none in existence.



The measurements have been given in metric system, now used by most of the scientific bureaus of the United States and universities and colleges of the country. In the old English system, formerly used in descriptive botany, the inch was divided into twelve lines. A ruler with this division is hard to find now-a-days, while metric rulers can be had nearly everywhere. For those who are more accustomed to the English measurements a table is given on page xii, with equivalents near enough for all practical purposes.

Habitat and Distribution

Near the end of each specific description is given the usual habitat of the plant and its geographic distribution. In order to save space the latter is given in abbreviation. Usually four states or provinces, or less, are mentioned; if the distribution is irregular, sometimes more than four. The expression: Man. Kans. Utah Alta. would mean that the area in which the plant grows naturally extends from Manitoba to Kansas, Utah, and Alberta. If a state or province is placed within parenthesis with a question mark preceding, as for instance (? Colo.), it means that the plant has been reported from said state, but that the author has not verified the assertion and doubts its correctness. Isolated or exotic distribution is set off from the general endemic one by a semicolon; and immigrants are distinguished as adventive (adv.), i. e., not fully established, or fully naturalized (nat.), or escaped from cultivation. The abbreviations used are included in the table on page xii.

Altitudes and Life Zones

In the original draft, altitudinal distribution was stated. In an area which extends in latitude 18 degrees, or approximately 1250 miles, however, a statement of the altitudes does not mean very much, as a plant which has its best develop- ment in Colorado at 3000 meters (10,000 feet) does not reach half that altitude in the Canadian Rockies. Instead of the altitude in meters or feet, the zonal distribution is therefore given. The following life zones have been accepted in this work:

Alpine Zone (Alp.), the region above timberline.

Subalpine Zone (Subalp.), or Spruce Belt.

Montane Zone (Mont.), or Pine Belt.

Submontane Zone {Submont.), or Foothills, or in the south the Chaparral Belt.

Sonoran, or rather Upper Sonoran, Zone (Son.), or Pinon-Cedar Belt and the Upper Desert.

Lower Sonoran Zone (L. Son.) or Lower Desert, limited with the manual area to the Colorado River Caiion and Virgin River Valley in Utah.

As the first four of these zonal names apply only to a mountain region, they could not be used for the part of the area occupied by the plains, especially east thereof. The same life zone that occupies the high mountains in temperate latitudes will occupy the lowlands nearer the poles, and these zones there become Arctic, Subarctic, Boreal, and Subboreal. The Montane and Subalpine Zone reach the lowlands or plains in Alberta and hence also meet the western exten- sion of the Boreal and Subarctic Zones of the east. This merging takes place, however, mostly north of latitude 55°, as the grass-covered plains i)ush across the northern branch of Saskatchewan River; it is practically only along the lower part of said river that the Boreal and Subarctic flora enters the area of this work. The hardwood forests of the subboreal zone docs not reach the Rockies; only a small element roj>rcsents it in the foothills of the Black Hills, South Dakota, and exceedingly few of its j)lants reach eastern Saskatchewan. The zone is ro})re- sented on the j)lains by grasslands and as these arc so different from both the foothills of the Rockies and the eastern subboreal hardwood forest, it has seemed better to designate them with a different name, and the word Plain represents the grass-covered portion of the Subboreal Zone. The plains south of the divide between the Arkansas and Platte rivers belong in reality to the Sonoran Zone, but as the transition is so gradual and the general characters of the two divisions


are much alike, in many cases the word Plain also includes the Sonoran portion of the plains, the so-called Slaked Plains. Tables showing the approximate altitudes occupied by the different zones in southern Colorado and southern Montana, and in Alberta at the crossing of the Canadian Pacific Railroad, and also the approximate latitudes at which they meet the plains, lowlands, or level basins are shown below.

The western side of the mountains is warmer than the eastern. It is also dryer, except in the northern part, where the moisture conditions are reversed. The lower zones, therefore, extend further north on the west side.

Colorado Montana Alberta

Alpine {Alp.) 3500-4300 m. 2700-3.500 m. 2100-3500 m.

Subalpine (Subalp.) 3000-3500 m. 2500-2700 m. 1800-2100 m.

Montane {Mont.) 2.500-3000 m. 1800-2500 ra. 1200-1800 m.

Suhmontime {Submont.) . . . 1800-2500 m. 1500-1800 m. Plain

Upper Sonoran (Son.) 1350-1800 m. Plain

This table may be given also in the English measures:

Alpine 11,500-14.400 ft. 9.000-12,000 ft. 7,000-12.000 ft.

Subalpine 10,000-11,500 ft. 8.000- 9,000 ft. 6,000- 7.000 ft.

Montane 8,000-10,000 ft. 6,000- 8,000 ft. 4.000- 6,000 ft.

Submontane 6,000- 8.000 ft. 5,000- 6,000 ft. Plain

Upper Sonoran 4,500- 6.000 ft. Plain

The different zones meet the lowlands, plains or level basins at approximately the following latitudes:

East side West side

Alpine-arctic 69°-90° 69°-90°

Subalpine 55°-69° 55°-69°

Montane 48°-55° 50°-55°

Submontane 38° 30'^8° 42°-50°

Upper Sonoran 35°-38° 30' 35°-42°

Time of Flowering

At the end of the specific description is given the month of flowering. The symbols used are: Ja, F, Mr, Ap, My, Je, Jl, Au, S, O, N, D.



The well known abbreviations of the states of the United States are here litted.

Adv. = adventive

Alp. = Alpine Zone

Alta. = Alberta*

Am. = America or American

Ap = April

Arctic = Arctic Zone

Au = August

Auth. = Authors t

B. C. = British Columbia Boreal = Boreal Zone

c = central

C. Am. = Central America cm. = centimeter

D = December

dm. = decimeter

e = eastern

Eu. = Europe

Eurasia = Europe and northern Asia

F = Februarv

(Fl. Colo.) =' The Author's Flora of

Colorado (Fl. Mont.) = Catalogue of the Flora

of Montana and Yellowstone Park Greenl. = Greenland Ja = Januarj' Je = June Jl = July Labr. = Labrador L. Calif. = Lower California L. Son. = Lower Sonoran Zone m. = meter

Mack. = Mackenzie Territory Man. = Manitoba Mex. = Mexico!

mm. = millimeter

Mont. = Montane Zone

Mont. = Montana

Mr = March

My = May

n = northern

N = November

N. Am. = North America

Nat. = Naturalized

N. B. = New Brunswick

ne = northeastern

Ne^\'f. = Ne'R'foundland

N. S. = Nova Scotia

nw = northwestern

O = October

Ont. = Ontario

P. E. L = Prince Edward's Island

Plain = Subboreal Plains

Que. = Quebec

s = southern

S = September

S. Am. = South America

Sask. = Saskatchewan

se = southeastern

Son. = Sonoran Zone

Subalp. = Subalpine Zone

Subarctic = Subarctic Zone

Subboreal = Subboreal Zone

Submonl = Submontane Zone

sw = southwestern

Trop. = tropical

w = western

W. Ind. = West Indies


- (short dash) between figures or words means that the two figures or two words denote the extreme of varia- tion.

5 Subgenus or section of a genus.

(long dash) between the names of two or more states denotes the extent of distribution.

X denotes a hybrid between the two species mentioned.


1 mm. = V2.-3 inch

3 mm. = Vh inch

1 cm. = % inches

5 cm. =2 inches

1 dm. = 4 inches

] rn = 40 inches or 3K feet

300 m. = 1000 feet

1 line = 2 mm. i/g inch = 3 mm. 1 inch = 2.5 cm. 1 s])an = 1 dm. 1 foot = 3 dm. 1 yard = 9 dm.

* Many people ase the abbreviation "Alb.", but as far as the author has been able to a-scertain, the official one i.s ".\lla." .,.«..••.. 5 v,

t Used in cases of misapplications of names where the author first asmg it in sucn a sense has not been ascertained. >

t Observe the difference between N. M. (New Mexico) and n Mex. (northern Mexico).



Seed-bearing or Flowering Plants.

Plants with flowers containing stamens, or pistils, or both, and producing seeds containing an embryonic plant. Alternation of generations not apparent, the gametophyte being exceedingly re- duced. The pollen-grains {microspores) contained in the anther- sacs of the stamens, after liberation and reaching the stigma of the pistil or the naked ovules, germinate and produce a tube, by means of which the egg-cell {macrospore) of the ovules {macrosporange)

is fertilized.

Page Ovules and seeds borne on the surface of an open bract or scale; stigmas wanting.

Class I. GYMNOSPERMAE 11 Ovules and seeds in a closed ca\'ity (ovary), formed by one or more united modified leaves, with one or more stigmas at the end.


Cotyledons usually single; earlier leaves alternate; leave.s mostly parallel-veined;

stem endogenous. Subclass 1. Monocotyledones 20

Cotyledons mostly 2; earlier leaves opposite; leaves mostly netted- veined ;

stem e.xogenoiis. Subclass 2. Dicottledones 185

KEY TO THE FAMILIES. Class 1. GYMNOSPERMAE. Naked-seeded Plants.

Perianth none; trees or slirubs with needle- or scale-like leaves not sheathing. Pistillate flowers in aments; fruit a cone, either dry or berry-like.

Carpellary scales subtended by bracts, never peltate; ovules inverted; buds scaly ; wings of the seeds formed from a portion of the carpellary scales,

1. Pinace.\e 11

Carpellary scales not subtended by bracts, mostly peltate or fleshy; ovules erect; buds naked; wings of the seeds, if present, a part of the seed- coat. 2. Jdntper.\ceae 17 Pistillate flowers single or in pairs, without carpellary scales; fruit drupaceous

or baccate. 3. T.\xace.\e 18

Perianth present, urn-shaped; pistillate flowers single or in pairs; horsetail-Uke shrubs with jointed branches and the leaves reduced to sheatliing scales.

4. EPHEDRACE.'i^ la

Class 2. ANGIOSPERMAE Seed-vesseled Plants.


Small lens-shaped, ellipsoid, or flask-shaped floating aquatics without leaves.

15. Lemnaceae 143

Plants with true stems and leaves, the latter however, sometimes scale-like.

Perianth rudimentary or degenerate, its members often bristles or mere scales, not corolla-like, or wanting. Flowers not in the axils of dry or chaffy bracts (glumes). Perianth of bristles or chaffy scales.

Flowers in elongate terminal spikes; fruit hidden among bristles.

5. Ttphace.\e. 20 Flowers in globose lateral spikes; fruit not hidden among bristles.

. , , 6. Spakganiaceae 20

Perianth fleshy or herbaceous, or wanting.

Flowers in dense spikes subtended by an enlarged bract (spathe) ; fruit baccate; endosperm present; emersed water or bog plants.

14. Araceae 143

Flowers, if spicate, not subtended by a spathe; fruit drupaceous; endosperm wanting; submerged water plants.



Gynoecium of distinct carpels; stigma disk-like or cup-like.

7. Zanichelliaceae 21 Gynoecium of united carpels; stigmas 2-4, slender.

8. N.\JAD.\CE.\E 26 Flowers in the axils of dry or chaffy, usually imbricate bracts (glumes).

Leaves 2-ranked, their sheaths with their margins not united; stem

mostly hollow ; fruit a grain. 12. Poaceae 29

Leaves 3-ranked, their sheaths with united margins; stems solid; fruit an

achene. 13. Cyperaceae 103

Perianth of 2 distinct series, the inner series usually coroUoid. Gynoecium of distinct carpels.

Petals similar to the sepals; anthers long and narrow; carpels coherent.

9. Scheuchzeriaceae 26 Petals different from the sepals, in ours white; anthers short and thick;

carpels not coherent. 10. Alismaceae 27

Gynoecium of united carpels.

Stamens numerous; water plants with broad netted- veined floating leaf- blades. 47. Nymphaeaceae 2S4 Stamens 3-6.

Ovary and fruit superior.

Stamens dissimilar, or only 3 with fertile anthers; endosperm mealy. Calyx and corolla of free, very different members; stamens

free. 10. Commelinaceae 144

Calyx and corolla of quite similar members and partly vmited; stamens partly adnata to the perianth.

17. Pontedehiaceae 145 Stamens alike and fertile; endosperm fleshy, horny, or cartilagin- ous. Styles present, distinct or united; stigmas terminal.

Styles distinct; capsule septicidal. 18. Melanthaceae 146

Styles united, often very short or obsolete during anthesis. Petals and sepals very unlike; capsules septicidal.

24. Calochortaceae 171 Petals and sepals nearly aUke; capsules locuUcidal.

Sepals and petals chaffy. 19. Juncaeae 149

Sepals and petals not chaffy.

Herbs with bulbs, corms or rootstocks.

Plants with bulbs, or corms, or short erect rootstocks. Flowers in umbels, at first included in and later subtended by a scarious invo- lucre. 20. Alliaceae 157 Flowers solitary or racemose, or in Leuco- crinum by shortenmg of the stem the inflorescence umbel-like, without involucre. 21. Liliaceae. 163 Plants with elongate horizontal rootstocks.

22. Convaiaariaceae 166 Shrubby plants with woody caudices, or trees.

23. Dracaenaceae 169 Styles wanting.

Flowers perfect; plants not climbing.

Leaves and bracts alternate; plants with bulbs; fruit

a capsule. 24. Calochortaceae 171

Leaves or leaf-like bracts whorled; plants with rootstock;

fruit a berry. 25. Trilliace.\E 172

Flowers dioecious; plants climbing or trailing.

26. Smiiacaceae 173

Ovary and fruit wholly or partly inferior .

Flowers regular; androecium not reduced; stamens 3 or more. Aquatic plants, dioecious or polygamous.

11. Elodiaceae 28

Land-plants with perfect flowers.

Stamens 6; leaves not equitant. 27. jVM.\RyLLTDACEAE 173

Stamens 3 ; leaves equitant. 2S. Iridaceae 173

Flowers irregular, perfect; terrestrial or epii)liytic plants; stamens

1 or 2. 29. ORCinDACE.\.E 176


A. Corolla wanting.

I. Calyx wanting, at least in the staminate flowers.

Herbs. .

Land plants; styles di.stinct, cleft or fohaceous; ovaries 3-celled.


Aquatic plants; stylos simple, imited into pairs; ovaries 4-celled.

75. Callitkiciiaceae 547 Trees or shrubs.

Fruit 1 -seeded; seeds without tufts of hairs.


Fruit a nut or an achene. 33. Corylaceae 205

Fruit a drupe or a samara. 101. Ole.aceae 655

Fruit many-seeded; seeds eacb with a tuft of hairs.

30. Salicaceae 185 II. Calyx present at least in the staminate or in the perfect flowers.

1. Flowers, at least the staminate, in aments or ament-like spikes.

Plant not parasitic; fruit a nut or an achene.

Staminate and pistillate flowers both in aments; fruit not with a bur or cup. Staminate flowers 2 or 3 together in the axils of the bracts, each with a calyx; pistillate flowers without a calyx.

32. Betulaceae 202 Staminate flowers solitary in the axils of each bract, without a

calyx; pistillate flowers with a calyx.

33. Coryl-aceae 205 Staminate flowers in aments; pistUlate ones often solitary.

Fruit a nut, at least partly enclosed in a cup or bur.

31. Fag.\ce.\e 199 Fruit drupaceous, not enclosed in a cup or bur.

{Garrya in) 95. CORNACEAE. 634

Plant parasitic; fruit borry-like. 125. Loranthaceae 816

2. Flowers, at least the staminate, not in aments.

a. Ovary superior.

Gynoecium of 1, or several and distinct carpels; stigrma and style of each solitary.

Carpel soUtary.

Ovary neither enclosed nor seated in a hypanthium or a calyx- tube. Flowers not solitary in the a.xils of the leaves ; land plants. Plants with scarious stipules; flowers cymose.


Plants not with scarious stipules ; flowers clustered.

36. Urticaceae 208 Flowers soUtary in the a.xils of the leaves; aquatic plants.

46. CERATOPHYLL-ACEAE 284 Ovary enclosed in or seated in a hypanthiiuii or a caly.x-tube. Stamens borne under the gynoecium; calyx coroila~like ;

herbs. 40. Nyctaginiaceae 255

Stamens borne on the hypanthium or adnate to the calyx- tube; calyx not coroUa-Uke; shrubs. Hj-panthium becoming fleshy in fruit, enclosing the tail-less achenes; calyx 4-nierous; stamens 4