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                                 BOTANY

                                   OF

                      THE NORTHERN UNITED STATES.




                                 MANUAL
                                   OF
                               THE BOTANY
                                 OF THE
                        NORTHERN UNITED STATES,

           INCLUDING THE DISTRICT EAST OF THE MISSISSIPPI AND
                 NORTH OF NORTH CAROLINA AND TENNESSEE.


                              BY ASA GRAY,
    LATE FISHER PROFESSOR OF NATURAL HISTORY IN HARVARD UNIVERSITY.


                             Sixth Edition.


          REVISED AND EXTENDED WESTWARD TO THE 100th MERIDIAN,
                                   BY
                             SERENO WATSON,
           CURATOR OF THE GRAY HERBARIUM, HARVARD UNIVERSITY,
                                  AND
                            JOHN M. COULTER,
                 PROFESSOR OF BOTANY IN WABASH COLLEGE,

              _ASSISTED BY SPECIALISTS IN CERTAIN GROUPS_.


                        WITH TWENTY-FIVE PLATES,
             ILLUSTRATING THE SEDGES, GRASSES, FERNS, ETC.


                     IVISON, BLAKEMAN, AND COMPANY,
                             _PUBLISHERS_,
                         NEW YORK AND CHICAGO.
                                 1890.

                           _Copyright, 1889_,
            BY THE PRESIDENT AND FELLOWS OF HARVARD COLLEGE.




CONTENTS.


                                                           Page

PREFACE                                                       1

SYNOPSIS OF THE ORDERS                                        5

ANALYTICAL KEY TO THE ORDERS                                 19

EXPLANATION OF ABBREVIATIONS OF AUTHORS' NAMES               30

EXPLANATION OF SIGNS                                         32

FLORA.--PHAENOGAMOUS OR FLOWERING PLANTS                      33
            Dicotyledonous or Exogenous Plants               33
              Angiospermous, Polypetalous                    33
                             Gamopetalous                   216
                             Apetalous                      425
              Gymnospermous Plants                          489
            Monocotyledonous or Endogenous Plants           495
        CRYPTOGAMOUS OR FLOWERLESS PLANTS                   675
            Vascular Acrogens, or Pteridophytes             675
            Cellular Acrogens, or Bryophytes (Hepaticae)     702

ADDITIONS AND CORRECTIONS                                   733

TABLE OF ORDERS                                             736

GLOSSARY                                                    738

INDEX                                                       749

PLATES, WITH EXPLANATIONS                                   761




PREFACE.


The first edition of Gray's Manual was published in 1848. It was to a
great extent rewritten and its range extended in 1856, and it was again
largely rewritten in 1867. The great advances that have since been made
in systematic botany and in the knowledge of our flora have for several
years past made another revision desirable, which Dr. Gray before his
death was purposing to undertake.

The present editors, acting to the best of their ability in his stead,
have endeavored throughout to follow his methods and views. The original
plan, so long retained by Dr. Gray and so generally approved, has been
closely adhered to, the characters and descriptions of the last edition
have been left essentially unchanged so far as possible, and in the
numerous alterations and additions that have been considered necessary
or advisable, his conclusions and principles have governed in every
matter of importance, so far as they could be known. The effort
especially has been to maintain that high standard of excellence which
has always made the Manual an authority among botanists.

In the treatment of the genera and species, Gray's Synoptical Flora has
been made the basis in the revision of the Gamopetalous Orders, and the
manuscript in continuation of that work, so far as prepared, for the
Polypetalous Orders which precede _Leguminosae_ (excepting _Nuphar_, the
_Cruciferae, Caryophyllaceae, Vitis_, and the small Orders numbered 18,
22, 23, 25-27, and 29). The genus _Salix_ has been rewritten for this
edition by M. S. BEBB, Esq., the genus _Carex_ by Prof. L. H. BAILEY,
and the Ferns and allied orders by Prof. D. C. EATON. For the rest, all
known available sources of information have been made use of, and much
willing help has been received from botanists in all parts of our
territory.

The increasing interest that is taken in the study of the Cellular
Cryptogams, and the desire to encourage it, have led to the inclusion
again of the Hepaticae, which were omitted in the last edition. These
have been prepared through the kindness of Prof. L. M. UNDERWOOD, though
the limits of the volume have necessitated somewhat briefer descriptions
than he considered desirable. The three fine plates illustrating the
genera of these Orders, which were used in the early editions, are also
added, with a supplementary one, as well as an additional one in
illustration of the Grasses, thus increasing the number of plates to
twenty-five. A Glossary of botanical terms is appended, to meet an
expressed need of those who use the Manual alone, and a Synopsis of the
Orders in their sequence is given, to contrast more clearly their
characters, and to show the general principles which have determined
their present arrangement. This should be a useful adjunct to the more
artificially arranged Analytical Key.

GEOGRAPHICAL LIMITS, AND DISTRIBUTION.--The southern limit of the
territory covered by the present work is the same as in the later
previous editions, viz. the southern boundary of Virginia and Kentucky.
This coincides better than any other geographical line with the natural
division between the cooler-temperate and the warm-temperate vegetation
of the Atlantic States. The rapid increase of population west of the
Mississippi River, and the growing need of a Manual covering the flora
of that section, have seemed a sufficient reason for the extension of
the limits of the work westward to the 100th meridian, thus connecting
with the _Manual of the Flora of the Rocky Mountain Region_ by Prof.
Coulter. These limits, as well as that upon the north, have been in
general strictly observed, very few species being admitted that are not
known with some degree of certainty to occur within them. The extreme
western flora is no doubt imperfectly represented.

The distribution of the individual species is indicated somewhat more
definitely than heretofore in many cases, so far as it could be
satisfactorily ascertained. The extralimital range is also sometimes
given, but the terms "northward," "southward," and "westward" are more
frequently employed, signifying an indefinite range in those directions
beyond the limits of the Manual. Where no definite habitat is specified,
the species may be understood as found more or less generally throughout
the whole area, or at least to near the western limits.

NOMENCLATURE, ACCENTUATION OF NAMES, etc.--In case of question
respecting the proper name to be adopted for any species, Dr. Gray's
known and expressed views have been followed, it is believed, throughout
the work. While reasonable regard has been paid to the claims of
priority, the purpose has been to avoid unnecessary changes, in the
belief that such changes are in most cases an unmitigated evil. Synonyms
are rarely given except where changes have been made. As a guide to
correct pronunciation, the long sound of the accented vowel (modified
often in personal names) is indicated, as heretofore, by the grave
accent (`), and the short sound by the acute ('). In regard to the
derivations of generic names, many valuable suggestions have been due to
W. R. Gerard, Esq., of New York.

PROMINENT CHARACTERS are indicated by the use of _Italic type_ for the
leading distinctions of the Orders, and generally in the specific
descriptions for those points by which two or more nearly allied species
may be most readily distinguished. The ready discrimination of the
gener