a text-book of botany

373 Pages·2013·27.57 MB·English

TWENTIETH CENTURY TEXT-BOOKS
A TEXT-BOOK OF BOTANY
FOR SECONDARY SCHOOLS
BY
~HN ~ (pULT ElL A. M., PH. D.
U£AO or Dr:f'ART~£1'M' 0' BOTANY, Tilt: U1fI\-EIl lTV
0" CItICAOO
NEW YORK
D. APPLETON AND COMJ'~NY
Co1"TllIGhT. 1105. ltV
D. APPLETON ~-D COMPANY
ENTIETH CENTURY TEXT-BOOKS
EOlTEU BV
A. f. NIGHTINGALE. PH. D. LL. D.
TEXT-BOOKS IN BOTANY
By John M: Coulter. Ph.D.
K&A.D OP nU'.u.'T.M..'tNT 0" llMJ.ST 1.'" 'rat GKn'"EllSrrV
01 CJlIC.AUO
T ext-Boo k of Botany. 12mo. llIW!trsted.
Oloth $1.25
Plant Studl... An Elementary Botany. 12mo.
Cloth $1.25
Plant Relation •. A First Book of Botany.
12mo. Clotb '1.10
Plant Structures. A Second Book of Bo~
any. 12mo. Olotb 'J.20
Plant• • The two foregoing in one 'Volume.
For Normal Schools and Oolleges. 12m.o.
Olotb $1.80
In the Twenti6i4 Centufl Seri6& of Text-BtIOks
D. Appleton and Company, New York
PREFACE
THE several editions of Plilnt StUJb~., designed for uso
in secondary schools, were combined abridgments of Plilnt
Relations and Plilnl Str!Jdurc8, Although this arrangemont
involved a certain amount of repetition and lack of conli
nuity, it was felt tbat tbese faults would be corrected by ,
the competent teacher, whose chier desire would' ~ to
secure points of view in reference to botanical material.
During the fiye years that have elapsed sinee the publi
cation of the first edition of Plilnt StudiCIJ, tbe opinions of
many experienced teacbers have been obtained, These
opinions hM'e been based upon repeated usc of tbe book,
and have been of the greatest possible ser\'ice in develop- ,
ing definite idens as to the adjustment of tbe subject to the
needs of the schools, Tbe natural outgrowth of tins co
operation between author and teacbers has been the prop
aration of the present TexlrBook of Botany, wbirl! sel'ks t.<I
express their combined judgment. 'Ihere, has been substan
lial agreement as to tbe nature of the material and Ihe
poiots of view, tbe only differences of opinion being such
minor ones or presentation as must always be found among
equally competent teachers,
There has been no attempt to treat the vanous di"iaiollll ,
vi PREFACE
of Botany separately, but rather to deyelop them all in their
most natural relationships; and yet morphology, pbysiology,
and ecology have been kept so distinct that the teacher will
have no difficulty in calling attention to these divisions, If it
is thought desirable.
, In the first five chapters tbe structure, iunction, and rela
tionships of the most obvious plant organs are considered.
The purpose has been to use the most easily observed ma
terial to give preliminary training in obse;vation and some
conception of the activities of plants.
The following thirteen chapters present an outline of the
plant kingdom in the simplest possible form to be at all ade
quate. In these chapters the morphological point of view
neceSSArily dominates, but not to the exclusion of the phys
iologhu and ecological. In this presentation of the great
groups, which is also an outline of classification, there have
been included special accounts of forms of economic interest;
not only because such forms as well as any others may
illustrate groups, but chiefly because there is a growing con
viction that Botany in the schools must relate pupils to their
COmmon experiences. IlS well as train them in science. For
the same general reason the brief chapters on plant-breeding
and forestry haye been introduced.
Tbe four closing chapters include a. yery brief account of
plant associations, the most inclusive view of plants. This
subject is merely introduced rather than deyeloped.
It cannot h\l repeated too olten that this book will not
serve its purpose unless it is used as a. supplement to the
teacher, to the laboratory, and to field-work. Furthermore
. it mllJlt be insisted that tbe sequence of tbe book need not be
PREFACE vU
the sequence used by the teacher. For example', work on
leaves, stems, roots, and seeds may come in any order, and
may well differ according to the availability of material or the
conviction of the teacher. Itso happens tbat the book hegins
with leaves, hut those teachers who pmfcr to begin with secd~
should do so.
In the matter of illustrations, there have been many im
provements, eliminations, and additions. All of this work
has heiin done or directed hy my assistant, Dr. W. J. G. Land,
whose skill in photography has been made use of freely and
whose cooperation has added much to the value of the book.
Unless otherwise credited, all illustrations have been prepared
for thls volume or those previously mentioned.
JOHN M. COULTER.
THE U~'IVER.SITY 0' CmCA.Go~
September, 1905.
CONTENTS
CILU"l'Ii:R ""'GIL
I.-INTuODUCTIO:S
A1I.-LEAVES
/nI.-'sTEMS . 41
,IV.-Roo:rs . il
,A'.-GEmn.~AT10X 01" SEEnS 84
YI.-ALa.., !)8
VH.-FUNGI . [29
vrrr.-Ln"ERWORTS · 165
IX.-MOMES . · 175
x..-FERNS . · I 3
XI.-HORBETAU..s AND CLVO-r..tOSSCS · 197
A"1I.-GYl\["~OSPERMS · 207
>;IIL-A... . GIOSPERMS . . . · 220
/)av.-FLoWERS AND INSEcrs . · 242
/XY.-'sE1':D DISPERSAL • · 255
hvI.-MO~OOOTYL£DON8 . · 262
....xVII.-DICOT1.l..E'OObO'!S: ARCIllCULA."YDE~ · 282
"VllI.-DlOOT\'LEOONS: SYlfPETA.L& . .302
XIX.-PL"\"'<T-tlREEDlNG . · 316
-XX.-FORESTRY · 320
x.."'{l.-PLAST AssoCIA'1'lOll,"S .324
XXn.-Hl'"DROPItYTES · 328
XXIII.- XEROPH"\'"TES .337
XXIV .-M:!:soPffYTE5 · 345
INl)EX • '.357·
A TEXT-BOOK OF BOTANY
FOR SEOONDARY SOHOOLS
CHAPTER I
INTRODUCTION
1. Occurrence of plants.- Plants form the natural cover
ing of the earth's surface. So generally is this true that a
land surface without plants seems remarkable. Not only
do plants cover the land, hut they abound in waters as well,
both fresh and salt waters. One of the most noticeable
{acts in regard to the occurrence of plants is that they do
not form a monotonous covering for the earth's surface,
but that there are forests in one place, meadows in another,
swamp growths in another, etc. In this way the general
appearance of vegetation is exceedingly varied, and each
appearance tells of certain conditions of living.
2, Plants as Jiving tbings.-It Is very important to
begin the study of plants witl! the l.. .n owledge that they are
alive and at work. It must not be thought that animals
are alive and plants are not. There is a common impression
that to be alive means to have the power of locomotion,
but this is far from true; and in fact some plants l,ave the
power of locomotion and some animals do not. Both plants
and animals are lhing forms, and the laws of living that
animals obey must be obeyed also by plants, Of course
there are differences in detail, but the general principles
f Ii ving are the same in all living forms. To begin' with the
1
2 A TEXT-BOOK OF BOTANY
thought that plants are alive and at work is important
because this fact gives meaning to their forms and structures
and positio:ll!. For example, the structure of a leaf has no
meaning until it is discovered how its structure enables the
leaf to do its work.
3. The plant body.-Every plant has a body, which may
be alike throughout or may be made up of a number of
different parts. If one part of the body does not differ from
another, the plant is said to be simple; bnt the most con
spicuous plants, those with which everyone is best ac
quainted, are made up of dissimilar parts, such as root,
stem, and leaf, and such pla"ts are said to be complex.
imple and complex plants do the same work; but in the
simple plant the whole body does every kind of work, while
in the complex plant different kinds of work are done by
different regions 01 the body, and these regions come to look
unlike when different shapes are better suited to different
kinds of work, as in the case of leaf and root.
4. Plant organs.-The diiferent regions of the plant
body thus set apart for special purposes are called organs;
and complex plants have several kinds of organs, just as the
human body has bands, feet, eyes, etc. The advantage of
this to tbe plant becomes plain by using the common illus
tration of the difference between a tribe of savages and a
ch'ilize<! community. The SI"'ages all do the same things,
and each savage does eyerything. In the ciyilized com
munity some of the members are farmers, otbers bakers,
others tailors, otbers butchers, etc. This is i-.""1l0Wll as
"dh'ision of labor," and one great advantage it has is that
every kind of work is better done. Several kinds of organs
in a pl:rnt mean to the pl:.nt jn t what dh'ision of labor
means to the community; it results in better work and more
work.
5. Plant work.-Although many different kinds of work
. are 'being camed on by plants, all the wo~k may be put