LIBRARY OF CONGRESS,
COPYRIGHT OFFICE.
No registration oft#te of this book
as a preliminary to copyright protec-
tion has been found.
JUN 15 1910
Forwarded to Order Division 25.
(Apr. 5, 1901—5,000. ) Yad |
A passion flower.
Fig. 77.
Photographed by the late Dr. J. R. Weist.
NATURE STUDY
ONE HUNDRED LESSONS ABOUT
PLANTS
BY
DAVID WORTH DENNIS,
A)
Professor of Biology in Earlham College.
With More Than One Hundred and Fifty Illustrations.
Marion, Indiana.
TEACHERS JOURNAL PRINTING Co.,
1906.
CopyricuHt, 1903,
BY
O.W. FORD & CO.
Received from
Copyright Office.
JUN 161910
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PREPACE
Nature Study is new; Liebig was the first man who used a labora-
tory for instruction. He began his career as a teacher in 1824.
Courses in mathematics and language have had centuries in
which to perfect their methods of instruction and the lessons it is
best to offer; for this reason, lessons in these subjects are good,
if not the best, that can be offered, and the methods of giving
them have had opportunity to eliminate errors. The teacher of
nature study has almost no past to guide him. The older teachers
of nature study were not themselves taught in schools. As a
department of instruction it is without traditions or precedents.
Every serious teacher so far.has had to pave his own road. All
teachers have gone different roads. It could not be otherwise.
The material with which nature study deals, is inexhaustible; no
one can ever be acquainted with more than an insignificant frac-
tion of it. Itis all good. It will always be the case that success-
ful teachers will give what they know. They will accordingly
teach different things. It is probably true that every successful
teacher has, from year to year, taken his pupils over different
ground, and that everything done has proved to be good. What it
is best to teach we cannot yet tell, in other words, than that that
material is best-which can be had.
This nature study work has passed through three phases. It
was first taught from books. The only nature study work I ever
did in school was in Geography and Physiology and every syllable
of these came from books. We next added the laboratory. How
new this phase of the subject is, may be learned from the presi-
dential address of Dr. Wiley before the Indiana Science Teachers’
Association at Lafayette, in 1895. He says: “Prior to 1863 no
laboratory instruction was given in Indiana except a little in
qualitative analysis.”’
Much has come from the laboratory as a means of instruction.
But we had not been trying it long when we learned that though
the laboratory, like the book, is a great help, still it is not enough.
Aristotle had set us our task; Zoology has its end not in what an
animal is or what it does, but why it does it. Fitness is the real
Zoology. We had studied the sucker in books and learned much;
Vi Preface.
we brought him to the laboratory and learned more, but the sucker
had spots. Why did he grow them? We had to go to the brook
for answer; his spots resemble the stones on the bottom of the
stream. He grew them in imitation of this bottom, and he thus
often escaped his enemies. This brought us to the third phase,
the outing. This is now in full swing; nature study of whatever
degree cannot do without it. The Gulf Stream and the Rocky
Mountains we cannot take. to the school, but we can and do take
the school to them.
It is now known that nothing we ever did was wholly wrong.
The book, the laboratory, the outing, all were necessary. This
book emphasizes the outing, but contemplates the use of book and
laberatory as well.
The outing, to be successful, must have a definite purpose and
nearly all the lessons and exercises here given hold up one thing
to be learned.
This one thing should be important. The teacher and pupil
alike should be able to see that the lesson is worth while. Terns
incidentally necessary to the learning ot the lesson should be
acquired by use first. Let definitions wait until they are needed.
The excuseless thing that nature study has done is: it has piled
up definitions of parts, forms, disguises, etc., by the hundreds
of pages and has turned them on in installments, away from what
they represent and apart from any possible use that the learner
could see. This book has been written with the conviction that
this ought to stop. If it has left undefined any necessary terms
for any lesson, Webster, Worcester or the Century at least, will
supply the omission.
It has been the constant aim of these pages to put the student in
possession of guiding principles,—something that will help him
interpret what he sees. Nearly all the lessons consider, in one
form or another, the plant in question as a species that has won
in the struggle for existence and they direct attention to the adap-
tations that have enabled it to win.
It is my conviction that knowledge on the part of the teacher
is the chief thing we lack. This consideration has led me to con-
fine these lessons to a field so limited that it would be possible for
the faithful teacher to gain the necessary knowledge. I do not
see how IJ could. give these lessons without knowing the plants in
question by name. This is the first thing children ask and the
best way to induce them to learn the important things the teacher
assigns is for him to tell them the unimportant (?) things they
Preface. vil
ask. These lessons mainly deal with common trees; but a teacher
should have a good manual of botany and know how to use it to
find the name of a plant. For the Ohio Valley, Gray’s Manual
is a good one for determining the names of flowering plants. Ap-
gar’s Trees of the Northern United States will enable any teacher
to find the name of most, if not all, trees by their leaves only.
A good general botany is Campbell’s University Botany. Three
good smaller works are Bailey’s Elementary Botany, Coulter’s
Plant Relations and Plant Structures, and Atkinson’s Elementary
Botany. The catalogue prices of these books and their publishers,
are as follows:
Bailey’s Elementary Botany, The Macmillan Co., $1.10.
Coulter’s Plant Relations, $1.10; Coulter’s Plant Structures, $1.20, D. Appleton
& Co.
Atkinson’s Elementary Botany, Henry Holt & Co., $1.25.
Campbell’s University Botany, The Macmillan Co., $4.00.
Apgar’s Trees, The American Book Co., $1.00.
Gray’s Manual, The American Book Co., $1.65.
A summer term in some lakeside or seaside laboratory, would be
of the greatest value to any prospective teacher of nature study.
It may be depended upon that in science, with fullness of knowl-
edge, enthusiasm and some good way to teach, will follow.
There is another sort of literature that the teacher should use
for the sake of the pupil: Stories and poems by masters that treat
directly or indirectly of plants. Only selections should be used
that are worthy; that belong to enduring literature. The follow-
ing list will show the character of the reading to which I refer:
Bryant, “The Yellow Violet,’ “‘The Fringed Gentian,’ ‘“‘The Death of the
Flowers;’’ Wordsworth, ‘‘The Oak and the Broom,” ‘‘Daffodils’—‘‘I wandered
lonely as a cloud,’’ ““To the Celandine;’’ Emerson, ‘‘The Rhodora;’’ Burns, “To
a Mountain Daisy;’’ Dickens, ‘‘The Ivy Green;’’ Holmes, ‘“‘Album Verses:’’ Southey,
“The Holy Tree;’”’ Santine, “‘Picciola;’’ Thoreau, ‘“The Succession of Forest Trees;”’
Kipling, “The Jungle Books.”
In addition to these there are hundreds of other worthy refer-
ences to plants in the works of all our standard authors, from
Shakespeare to Riley. Hunt them up and they are yours.
NATURE STUDY AND THE, CHILD:
My last recommendation may be criticised or called sentiment
or anything else, so the critic remembers it concerns itself with the
child’s need; his nature; his demands; the child’s imagination is
fairly riotous and must be directed; because poetry and story
Vili Preface.
were the first phases of the world’s literary activity, they appeal
to the mind of the growing child. Let him have them, part of the
time, and let them wed him to his more serious nature study as
they are sure to do. It is maintained that the imagination is to
be cultivated, but not in connection with nature study. But sup-
pose history teachers fence their preserve the same way? and
teachers of religion and sociology?
It has been said that this child preference for poetry, story,
myth and the heroic, is a “‘passing phase;’’ the tadpole’s tail is a
“passing phase’ but the stronger you make it the further the
frog will be able to jump. Let the child enjoy nature study,
science can stand it in any event and will gain by it if it helps the
child. As his interest in the subject grows, his need of any fanciful
presentation will decline.
The child’s powers of observation are proverbial; his desire for
knowledge is keen; it is universal among normal children; his
curiosity leads him to ask questions; disapproval or even punish-
ment will not stop his questioning. He only leaves it off when he
despairs of an answer. His impossible questions mean only that
his mind is awake and hungry; show him something it is worth
while for him to see or tell him something worth knowing and
keep this up to the point of weariness; then let him rest; let this
go on through the grades and nature study will have done for him
its best. How many curious, inquisitive children and how few
curious, inquisitive men! Nature study, if anything, can remedy
this. In the past, from the kindergarten or home to the high
school or college, our instruction has been almost wholly in books;
during this period, the pupil’s confidence in his power to see often
almost wholly disappears. Ask a class of a hundred freshmen
to learn how many gills a crawfish has, and the many will go to
the library, the few to the brook. What a blessing nature study
would be if it could keep alive throughout the formative period,
the child’s native desire to know at first hand. It would give to
Preface. 1x
the race as many Aristotles and Darwins as child endowments
promise us. i
The child has tasks enough; tasks which he must not only do
but remember for the quiz. Why not interest him in something
without the imminence of a judgment day. Ten inspiring minutes
twice a day and an outing twice a week, when the weather is
suitable, with the blessed privilege which men universally enjoy
of forgetting if he wants to, will put a spirit into all his tasks that
will surprise every one in its results. The one big result will be
that learning will become attractive.
Ivam under obligation to Prof. Ht. B. Dormer, of Purdue, for
misuce 30. to Prof. J. BP. Thompson, of the Richmond High
School for Figures 29, 54, and 87, and to Mr. A. M. Mahaffy for
Figure 139; to Miss Helen M. Fiske for several drawings and to
Mr. George Bond, Mr. Vivian Floyd, Miss Ruth Trueblood and
Mr. Charles H. Frazee for permission to photograph microscopic
slides; all of these are credited in connection with the several
illustrations. >)... 53
Deciduous: Forests). 4.2... {4 ee eee 54
Evergreen: Leaves). Vicia data) oo) oe oe a)
Bs es) k i cle a ct ee 57
De Persimmon) Prec special Case... oaeeeen 29
The Influence ot the Wind ..j..)-. 3.) eee 60
The Leaf.
The: Poliage Léats.20 2. 62
One Duty of Green eaves. .-2. = re 64
Leaves in’ the Role ot Spines. 72...) 4) 65
Leaves inthe. Rolevot Bracts . 75 3s). 66
Leaves. in the Role of Sepals and Petals fee .sam
Leaves in the Role of Stamens... 725) sae 69
Leaves in the Roleof Pistils 2.) 2 =e 70
Leaves in the Role of Bud-Scales.............. fiat
eaves in the Rolelof Bullb=Scales 4. eee UD
The Pappus of the Dandelion’ .().).. -) aaa 74
The Blossom Endvof thesApple >. 2.) eee Tie
Leaves in the Role of Tendrils | \)2 4. 77
How Tendrils Behave. ..22......2 4. 78
How the Bean Finds i1ts?Pole. 2... 2. 232) 79
Seed Dispersal.
The Multitude of Plants. The Struggle for
Existence: 020... es. ba eel rr 80
The Winged Seed of the Linden... 5°.) 33am
Other Seeds with Wings 2. 322.. ..2 2.5) 5 83
The Dandelion’s Parachute =..:... Sasa eee 84
Other Pappus-Bearing Seeds]. a. 1.. 87
some Adaptations of the @histley] =... ae 88
Smaliness of Seeds and Spores... .). . een 89
The Spanish: Needle (2... Yo25 2. eee 91
Other Seeds thatCline? 97.000: a. > ee 93
Currents of Waters. i). (05 eee Os oe eee 93
Fruit. The Service of Animals that Eat it..... 94
Lesson
LXV.
LXVI.
LXVII.
LXVIII.
EXITX.
LXX.
LXXI.
LXXIl.
LX XIII.
LXXIV.
LXXV.
LXXVI.
LXXVII.
LXXVIII.
LXXIX.
LXXX.
LXXXI.
LXXXII.
LXXXITTI.
LXXXIV.
LXXXV.
LXXXVI.
LXXXVII.
LXXXVIII.
LXX XIX.
XC.
XCI.
XCII.
XCIIT.
Contents. X11
Page
se GDP ESU En AVE lara Wra ia (2 8 CM ae ae pean Oy en 95
SperimeCOa nv alcese 4 2s gs et Bee es es 96
Seecia sO hier auCes. Se lee Rigs obey he 2 nls oS 98
Pesceieiviswer sal PAM TEs SY iy cir es ee 99
Plant Societies.
RV gsee Ptids sas i: ee eee fe tire wa SL, 2 101
Mouccoscupse! Piaiie'. x05. Ae ok phe ae Ss 6 104
One Plant.Adapted to Live in Water.......v2-.. 105
WPS et LAS to Seg Ny cge Sore ele iat ee, hn Se 109
Adaptation to Moisture. Land Plants......... 111
Some Advantages of Mass Life. Society Life ...112
Pe Walkin the Woods: “Porestty +... 24 2.2... ie
Stems.
whe @rore-Vascilar Bundle gee...) ot. ba <: - 115
The Arrangement of the Fibro-Vascular Bun-
RCo r ide tinda NCI VS vale ose oS Ob pe 117
SLOW or Wood in anrimroegen! oo). 6 seo. te 119
Air iGet aa Ns, OS Se oid ce ce le ewe weds 4 oo 3 123
[el eau ates ACE Clee ae Rees alee: RPP se katy ee ego 124
Soe tik DT Ps os A Oa ten ene oe ee a 126
Why the Yellow Violet Comes so Early in
So(ahitae pea Lk os Pel eee ee Cig oo Oe |
1 BIST [eagle apa Op bite S45. a2 7 gk ep ee Sa Calg Ea 128
[ASL ESP ie ie Bll date epee Gun: ae fe ee an rater Gee 129
SERVE eC aRig a e SF ter ok, ie Ge Mena ok Huse (isi ean a Re 130
Wig Clover Wietps the Soule 2a iso > ses els es as 132
Uses of Plants.
Bed eaia bs aid ee ede A cae os ic ht 5 2 I ews 134
Pini asa OO nese Ae nh ee ce Oe Se on 155
Piteus and Ciorhine, Mediceme, ete’. 2... 2.2... -.136
| OEE etl Ove eran C6 RR Ok be) Le gaia ce ee 137
Pata sthlev brit bs a Sak sae a2 Y ies Gel ok 140
The Plant’s Chief Work. Saprophytic Plants ...144
Chigrapliy lly si cetera eco es 5 Fe RE ek cs 3s 146
NMI
XCIV.
XCV.
XCVI.
XOCVIT:
XCVIE.
XCIX.
C.
CI.
Contents
Protoplasm. .
Differences Between Animais-and:Plants....... 148
The: Respiration of Plants*....°) >. 3 150
The: Cell oye cae Dek a i5t
How Plants Multiply.
The Asexual Way, vie... a0 22 152
‘The Sexual Way 2. 22)... 5) 2 156
Growth from the Cell:to the Tree 2 3a eee 164
Cell Duties in a:-Many-Celled Plant. =a eae 164
Young Plants... os... SS 166
NATURE STUDY.
ONE HUNDRED LESSONS ABOUT
RIGAIN-ES.-
LESSON I.
Adaptation to Light.
The Disposition of the Branches of a Beech Tree.
Figure 1 shows a beech tree in its winter condition. It
“will be noticed that its lower branches droop; higher up they
ere—trorizontal: higher still they rise. Why is this? It
cannot be that gravity alone makes the lower branches
droop for it acts on all alike. Look more closely and see if
the disposition of all the branches of the beech tree is not
such as to get its leaves to the light to the best advantage.
During all our observations on trees we should test the
following: The one main purpose of the stem of the tree,
its trunk and its branches, is to get its leaves to the light.
Exercise: Every pupil should draw a beech tree as ac-
curately as he can, but it should show the disposition of the
Branches above reierred to, “A pencil is a good eye.”
Examine also a sun flower to see if it gets its leaves to the
light in a similar manner; do the petioles of the lower leaves
droop; and those of the middle leaves grow in a horizontal
direction while those of the uppermost leaves rise?
2 Nature Study
Fig. 1.
A beech tree showing howfits branches get their leaves to the light; the lower
droop, the middle grow straight, and the upper rise.
~~
Adaptation to Lighi 3
LESSON II.
Adaptation to Light.
The Tree Grown im the Open Country and the Forest Tree.
Visit a walnut, oak, ash, or wild cherry tree that has
grown in the open country and one that has grown-in the
Fig. 2
_ This walnut tree grew in an open field; light called and its branches responded
ni all directions. It was photographed at the same distance as Figure 3.
2 Nature Study ) =
forest. How high is the tree in each case? How high is the
first branch? It will be seen that in the open, every branch
has responded to the influence of the light, has lived and
Fig. 3.
This walnut tree grew in the woods; light was to be had from above only; its
lowest, shaded limbs died; it is a tall tree.
Adaptation to Light 5
has grown vigorously toward the light; horizontal branches
are sometimes found as large as considerable trees in the
forest. In the forest, neighboring trees have shut out. the
light and the ‘lower branches have died; the highest
branches, called upward still by the light, have grown and
grown until the result is what we call the monarch of the
forest. Fig 2 is a walnut tree grown in a field; Fig 3 isa
walnut grown in the forest. These photographs were made
at the same distance from the trees and correctly represent
their dimemsions. The circumference of Fig 2 is 934 feet;
that of Fig 3 is 434 feet. So the country tree is much the
older. The forest tree is, however, much taller and its
lowest limb is much higher. In the pine forests of Europe,
it is a business for some women, children and old men to
cut off the under branches that have died in the shade and
gather up others that have fallen and bind them in bundles
for kindling purposes.
Exercise: Find and draw a tree that has grown alone in
the country-and one of the same kind grown in the forest,
care being taken to draw them to a correct scale. Measure
both trees just as they grow.
How to Measure a Growing Tree.
First, measure the height of, your eye on the tree trunk,
and mark the spotc. Walk back 100 feet from the tree to
e and set up a pole between you and the tree so you can just
Beebe top of the tree d over the top of the pole a. Mark
the point on the pole b between your eye and the spot c.
Now measure the distance ab; we will suppose it to be 6
feet. Measure the distance eb from your eye to b; we will
suppose it to be 10 feet. Now the distance dc is as many
times ab as 100 feet is times eb. This is ten; therefore the
6 Nature Siudy
tree is 10 times 6 = 60; add to this the height of your eye,
4 feet, and you have 64 feet, the height of the tree. Or if
“you understand it—eb:ec::ab:de. 10: 100::6: height of the
tree above your eye.
iil
aL
= 2 SGT
Ke) 40 4 | ||
LESSON III.
Adaptation to Light.
The Branching of a Fu-Tree.
Figure 41s a fir-tree. You can tell a fir-tree from a spruce
or hemlock by its leaves which have no petioles, but are at-
tached to the branch by a slightly enlarged disk. Notice
how perfectly conical its top is; the light makes it so. Go
under the tree, close to the trunk and look up. )Youswall
see that the branches are bare except at the extremmmes:
The leaves have all died where they were in shadow. Be-
cause the branches grow gradually shorter from below
upward, the upper ones cannot shade the lower at their ends;
here the leaves grow. When a tree has one main branch
from root to top as this tree has, we call its branching
Adaptation to Light 7
excurrent. But it is far less valuable for you to remember
this than it is for you to understand that this is one way for _
every branch to get some of its leaves to the light.
Fig. 4.
A fir-tree; excurrent branching; every branch reaches a little farther than those
above it and so all get the light.
Exercise: Find a fir-tree and sketch it to a correct scale;
go back to the beech again and see if its branching is also
excurrent. See if you can find a fir-tree, the branches of
which droop like those of the beech.
8 Nature Study
LESSON IV.
Adaptation to Light.
The Branching of the Elm.
Figure 5 is an American elm in its winter condition.
Notice that there is no main trunk above its lowest branches.
Find the tree growing out by itself where every branch has
Fig. 5. ;
The elm; deliquescent branching.
an equal chance at the light. When a main trunk divides
up into two or more somewhat equal branches and these
/
Adaptation to Light 9
branches divide in somewhat the same way, we call this
method of branching deliquescent. But the important thing
for us to consider is whether every branch grows in-the
direction that will most quickly and certainly bring its
leaves to the light. If the attraction of the light is the
determining thing and there is a flood of it 1n all directions
should we not expect a symmetrical top like this?
Exercise: Draw the elm showing its manner of branch-
ing. Find twenty different kinds of trees and determine
for each of them whether the branching is most like the fir
emuae elm. Is the apple excurrent or deliquescent in its
branching? The cedar?
LESSON V.
Adaptation to Light.
Unequal Lighting.
You are sure to see lack of symmetry in a tree, grown
where one side is in light and one in shadow. Figure 6
shows a pitch-pine that has grown in a clump of evergreens.
The main branch on the light side is 18 feet long. The
longest branch on the other side is only 4 feet. A wild
cherry tree growing between a linden and a sycamore near
my home, is flat because it is shaded on two sides and not
on the other two; its expanse from the light side to the light
side is 40 feet while from the shady side to the shady side
is only 20 feet.
Exercise: Find a tree somewhere so grown that it has
little light on one side; it may be on the edge of a forest or
10 Nature Study
on the outside of a group of trees or near a building. Meas-
ure its expanse of branches and draw it to a scale. Find
Fig. o.
_ The pitch-pine; the branches on the shady side are to those on the sunny side
in length as 4:18.
enough such trees so that you will feel sure that the amount
of light is one important thing in determining vigor and
direction of growth.
Consider the lilies of the field, how they row.
.
Adaptation to Light 11
LESSON VE
Adaptation to Light.
Pendant Branchlets.
Notice Figure 64, Lesson XX XIX, and you will see that
‘ the circles of limbs are some distance apart; this leaves
light spaces between them in which pendant branchlets
have grown down and brought their leaves to the light.
Find a Norway spruce and see that this is one of its char-
acteristic habits of growth. You can tell a spruce from any
tree that closely resembles it by the short, brown stems of
its leaves. These pendant branchlets of the spruce give it
a peculiar appearance in the distance. It should be one
aim of our nature study work to name as many tiees as we
can by their figures at a distance of forty rods or so. The
European larch has the same habit. It can be told from
the tamarack, the tree that iooks most like it, by its pend-
ant branches.
12 Nature Study
LESSON VII.
Adaption to Light.
Horizontal and Vertical Branches.
Figures 7, 8 and 9 show three branches of Norway spruce;
7 grew directly upright; 8 shows a side view, and 9 the view
from below of horizontal branches. The vertical branch is
round; the leaves grow on all sides of the branch; they
Fig. 7. Fig. 8. Fig. 9.
Fig. 7. A round spruce branch; it grew upright and had light in all directions;
Fig. 8’was horizontal and is flat; if turned through 90 degrees it would appear as
wide as 7 or 9. Fig. 9 was horizontal and is seen from below.
Adaptation to Light : 13
grow in like manner on all sides of the horizontal branch but
the under leaves come around to the side in order to get to
the light. The same lesson may be equally well learned
from a hedge that is just ready to be trimmed; some of the
long, fresh shoots will be found growing straight up, and,
as there are eight rows of
leaves on the stem it will
appear round in full leaf,
Figure 11; other branches
will be found that have
taken a horizontal direc-
tion and the leaves of these
will have crowded together
on the two sides and the
branches will appear flat,
Figure 10. Apple or peach
branches will show the
same thing, only there are
but five vertical rows of
Fig. 10. Fig. 11. }/
Fig. 10, a hedge branch that grew hori-
zontal. It is flat. Fig. 11, a hedge .
branch; it grew upright and round. Drawn leaves on these branches.
from nature by Miss Helen M. Fiske. If a two-ranked stem like
beech, elm or hazelnut is studied it will be found that on a
horizontal branch the leaves lie in the plane of the branch
—look at right anglestoit. Ona vertical branch so grown
that its light comes from above the leaves have turned
ninety degrees on their stems and face the tip of the branch.
Examine and see if it is the petiole that brings the leaves
into these varying positions.
Notice that the leaves of the spruce are short and narrow
and that there are many vertical rows on the branches with
the leaves close together; the hedge has broader and longer
leaves with fewer rows and the leaves in its rows much
farther apart. Does this ratio hold generally for leaves;
the wider and longer the leaves the fewer the rows and the
farther apart?
14 Nature Study.
LESSON VIII.
Adaptation to Light.
The Behavior of the Petiole.
Examine a pumpkin-vine; it will be found that the peti-
oles that come out on the upper side grow straight and
spread their leaves out directly above; but petioles coming
from the under side curve round and then grow out at the
angle best suited to bring their blades to the light.
Examine a morning-glory or any other sort of twining
vine; the petioles that leave the vine on the side next to the
support all bend around so as to bring their blades to the
light. Make the same study of a Virginia creeper growing
on the side of a house. Is not the petiole of a leaf a con-
trivance to bring the blade to the light? Does it not grow
straight or crooked, long or short, up or down or out, in
order that it may do this? Pull a branch from the Lom-
barday poplar; its branches cling close to the tree anem
almost straight up. Have the petioles all browehriiiices
blades around so as to face the light?
Adaptation to Light. 15
LESSON IX.
Adaptation to Light.
The Behavior of the Petiole. Maple Spray
Fig. 12.
A maple spray, showing the longer
petioles of lower leaves.
Figure 12 shows a maple
spray. Study this figure
with a maple spray before
you. Study it at the tree;
for the direction of growth,
or the length of a petiole
will often be determined by
the shadow of leaves on a
neighboring spray or on
neighboring trees. Com-
pare the maple spray with
the beechspray, Lesson XV.
Notice that on the maple
branch there are four rows
on eaves . while. on the
beech branch there are but
two. Notice again that
beech leaves on the same
spray cannot shade each
other, that the” maple
leaves can and that they escape this calamity by the vary-
ing length of their petioles and their direction of growth.
It must be some trouble and expense to a leaf to grow a
long petiole, and if nothing is gained by it why should it
do so? Do not pass from this lesson till you can see why
the beech does not need long and short petioles, while the
maple does. Study Lessons IX and XV together.
16 Nature Study.
LESSON X.
Adaptation to Light.
The Aspen. The Prickly Lettuce.
The aspen, the Carolina poplar, the Balm of Gilead, the
Lombardy poplar and a few other rare poplars have the
petioles of their leaves flattened vertically so that the leaves
quiver in the slightest breeze. Study this feature of the
aspen tree if possible. Scott, in order to tell how perfect
the calm, says,
“Scarce the frail aspen seemed to quake.”
This quaking permits the light to fall on leaves that other-
wise would be in shadow.
The common prickly lettuce furnishes an interesting
study ; its leaves turn 90 degrees on their axes near the stem
so that the leaf stands edgewise; they also turn so as to
point in a general north and south direction from which it
is often called the “compass plant.”’. The effeemten aanm
these movements is to lessen the amount of light they re-
ceive. We must not get the notion that the more light the
better for a plant, for plants can get too much light as well
as too little; in tropical and semi-tropical countries plants
have many ways of dodging or tempering the extreme light,
see Lesson LXXII and especially the cross-section of a
purslane leaf, Figure 117.
Adaptation to Light. ig
LESSON XI.
Adaptation to Light.
The Shape of the Leaf-Blade.
Figure 15 isa leaf of acut-leaved maple. Figure 12 shows
leaves of the Norway maple. Go close up to the Norway
maple and see it “‘as the squirrel sees it.’’ Its branches are
bare; now visit the cut-leaved tree; its branches are all cov-
Fig. 13. ; Fig. 14. Fig. 15.
Fig. 16. Fig. 17. Fig. 18.
_ Figs. 13 and 17. Notched, pinnately veined leaves of yellow chestnut-oak.
Fig. 14. Round-lobed leaf of white oak. Fig. 15. Cut-leaved maple leaf. Fig.
16. Awned, lobed leaf of red-oak. Fig. 18. Pinnately compound leaf of clematis.
ered with small branchlets, bearing many leaves. Is not
the reason for this that the sunlight sifts through between
the leaf-lobes of the cut-leaved maple, while the broad leaf
18 Nature Study.
of the Norway maple shades the main branches so that
leaves cannot grow on their branchlets?
Exercise I: Estimate the number of leaves on a Norway
maple and a cut-leaved maple of the same size. Have we
not here on one tree a large number of leaves with small
Fig. 19. Fig. 20. Fig. 21.
Fig. 22.
Fig. 19. Palmately compound leaf of horse-chestnut. Fig. 20. A chestnut leaf.
Fig. 21. The palmately lobed leaf of the sycamore-maple. Fig. 22. A moun-
tain-ash, odd-pinnately compound.
working surface doing for one tree what a much smaller
number of leaves with large blades do for another?
When the thermometer is 100 degrees in the shade, try
the shade of these two trees. Try the shade of the locust,
ash, walnut or Kentucky coffee tree in the same way; all of
them have pinnately compound leaves somewhat like
Figure 22. The light can filter through between the leaflets.
Adaptation to Light. 19
The pine has needle-shaped leaves; has it more leaves
than the sycamore? ‘Try to estimate the number of leaves
on trees about the same size. Try also the shade of the
pine. The light can sift through between its needles to
leaves below.
Exercise II: Find young trees, five to fifteen feet high,
Fig. 23. Fig. 24. _ Fig. 25.
Fig. 26. Fig. 27.
Fig. 23. Entire, heart-shaped leaf of lilac. Fig. 24. A greenbriar leaf showing
stipules changed to tendrils. Fig. 25. A stipulate leaf of rose. Fig. 26. Oblique
leaf of American elm. Fig. 27. Parallel-veined leaf of ginkgo.
growing in the shadow of a forest. Why have they larger
leaves than similar undergrowth where the light is stronger?
See if it is possible to make out a ratio between the size of
the leaves and the intensity of the light; that is, that a
larger leaf in a weaker light is required to do as much work
as a smaller leaf in a stronger light.
20 Nature Study.
oo
Fig. 28.
The rosette leaf-arrangement. A mullein of the first year
Adaptation to Light. 24
LESSON XII.
Adaptation to Light.
The Rosette Leaj-Arrangement.
Figure 28 shows a mullein at the close of the first season
of growth. Suchamullein can be found in October. Three
things are to be noticed; each leaf grows out between two of
a lower circle; the upper leaves are smaller than those below
them so they do not shade them much; the upper do not lie
flat as the lower do and for this reason shade the lower less.
How many leaves in the mullein, Figure 28, can get the
light? How many in the mullein you are now studying and
comparing with the cut? Draw accurately, as to direction
of growth and size, the leaves of the mullein you have found.
The mullein, thistle, cabbage and many other herbs are bi-
ennials; that is, they require two years to mature seeds.
During the first season they store up the food which they
will use the next in maturing the seed. A necessary part of
the work of preparing the food stored in the root is done in
the leaf, see Lessons XCII and XCIII. The October mul-
lein is getting ready for the stalk and seeds of next year.
Figure 54 shows the seed bearing mullein of thesecond year.
LESSON XIII.
Adaptation to Light.
The Stem’s Main Duty.
The stem, (in the case of a tree, the trunk and branches, )
holds the leaves up to the light; this main duty imposes upon
it the additional duty of bringing nourishment and moisturt
up from the ground and of supporting the top againse
22 Nature Stuay.
storms. It may be noticed that trees grown in rich soil
have much larger and taller trunks and branches than those
grown in poor soil; oak forests in sand, as those at Oak
Bluffs, Mass., are barely a third as high as those of our
northern states. As one travels toward the north, trees
become smaller and smaller until they at last trail beneath
the snow. One notices the same thing in ascending a
mountain; our prairie sunflowers in western Indiana and
Illinois are fifteen feet high or more; as one goes west he sees
Fig. 29.
Birches on Mt. Katahdin. Photographed by Prof. J. F. Thompson.
them becoming lower and lower until at Denver they are
three feet; as he ascends Clear Creek canon the same short-
ening goes on; ascending Gray’s Peak one comes to brook
plains carpeted from the melting snows on one side to the
melting snows on the other with apparently stemless flowers,
the prairie sunflower and its congeners from the plains.
This seems to indicate that the stem is a great convenience
under favorable conditions such as our rich soil affords, a
necessity to be sure for large growth, but not for existence
eee
Adaptation to Light 23
ee
as roots, leaves and flowers are. Varying conditions of soil
and climate do not permit a plant to avail itself of the sun-
light to the same measure, so the stem varies as its environ-
ment varies.
Exercise: Compare plants of the same species grown in
different soils. When opportunity offers make the same
observations while ascending a mountain.
Fig. 30.
Onions and corn growing in loam, clay, and sand to show influnece of soil.
orn the Proceedings of the Indiana Academy of Science for 1902, by Prof. H. B.
ormer.
Figure 29 shows birches growing on top of Mt Katahdin,
Maine. They are not small because they are young, but
because the climate compels them to be. The main stem
has become a rootstock from which the dwarf branches grow.
Figure 30 shows on the left three onion plants, one grown
in loam, one inclay and onein sand; on the right are three
stalks of corn similarly grown. The effect of soil need hardly
24 Nature Study
be commented upon. The conditions of moisture, tempera-
ture and light were the same for all.
Exercise: Try raising potted plants in different soils.
Try the effects of various fertilizers on plants. The secret
of variations giving the fine greenhouse plants is due some-
times wholly to the fertilizer.
LESSON .XIV.
Adaptation to Light.
The- Sleep. oj. Plants.
It will be shown, Lesson XCIII, that plants utilize sun-
shine in their work by day. Stems and branches hold their
leaves up to the light and each petiole grows so as best to
bring its blade into proper relations to it. Figure 31 shows
an Abutilon photographed on a sunny day atnoon. Figure
32 shows the same plant in the same situation at 10:45 p. m,
Every leaf droops. The day expanse was 14 inches; the
right expanse, 9 inches.
Exercise: Grow squash, pumpkin, cucumber, eteymas
potted plants and measure accurately the positions of their
leafblades at midday and at midnight. The same measure-
ments may be made on shrubs that grow in the yard. A
good one to measure is redbud. Make also day and night
examinations of bean and pea, growing in the garden. In
the day time, every leaf is alert and adjusted to the light.
Can it be that plants sleep and wake, work and rest?
What causes the leaves to assume these different posi-
el
Adaptation to Light. 25
tions? We are accustomed to say that it is the stimulus of
the light; but this Abutilon assumes the erect position before
it becomes light. It begins to awaken about 4 a. m. and
Fig. 31.
Abutilon, photographed at noon.
is fully awake when it is light (January, 1903). It wakens
up in a dark room into which no ray of light comes, at its
usual waking hour.
26 Nature Study.
_ These night and day movements of plants are called
nyctitropic; they may be studied to advantage in clover
a ee ee SS ge a
Li Mla
Fig. 32.
Abutilon, photographed at 10:30 p. m.
and Oxalis. In Oxalis the leaves fall from the horizontal
position until they rest against the stem; in clover on the
Adaptation to Light. 27
contrary two of the three rise and bring their upper faces
together while the third leaf rises in such a manner as to
cover the two somewhat.
Campbell says these movements are to diminish the
radiating surface and prevent the loss of heat, but the
Abutilon, clover and Oxalis all make these movements in a
room that remains at the same temperature. Whether the
action was at first caused by the alternation of light and
darkness or by day and night changes of temperature or by
both, the habit is so established that the movement is
carried on, for a time at least,at a constant temperature and
in total darkness.
Examine leaves also at midday on a very bright day and
see if they respond to the stimuli and change their positions
in the presence of too much light and heat as well as too
little.
LESSON XV.
Adaptation to Light.
The Leaf-Arrangement of the Beech Tree.
An elm will do for this lesson as well. The leaf-arrange-
ment and bud-arrangement, when no buds are suppressed,
are the same for the same tree. The buds generally ap-
pear in the axils of the leaves, that is, just above the
attachment of the leaves to the stem. It will be seen that
the beech spray in full leaf is flat, that the leaves grow on
opposite sides only; that there are two rows of leaves only
on each branch; that consecutive leaves are 180 degrees
apart; that if a string is passed through a beech branch
from a leaf to those above it in order, the third leaf is over
the first as shown in Figure 33. By this arrangement no
leaf-blade can ever shade another on the same branch.
For this reason they do not need long petioles to bring them
to the light. Notice that they do not have long petioles.
28 Nature Study.
Test this proposition on every plant you can find: the
petiole of a leaf has for its main duty the task of bringing
the blade to the requisite amount of light. Compare Lesson IX
Fig. 33. Fig. 34. Fig. 35. Fig. 36.
Fig. 33. A two-ranked beech branch. Fig. 34. A three-ranked birch branch.
Fig. 35. A five-ranked apple branch. Fig. 36. A way to determine leaf- ~arrange-
ment. Drawn by Miss Helen M. Fiske.
Exercise: Draw a beech or elm branch. The drawing
should show for the purposes of this lesson that the petiole
is very short and that the leaves are two-ranked.
LESSON XVI.
Adaptation to Light.
Leaf-Arrangement.
In previous lessons reference was made to the two-
ranked leaves of beech, the eight-ranked leaves of hedge
and the five-ranked leaves of apple. It was necessary to
do this in order to study the light adaptations.
Exercise I: Get straight young branches of elm, beech,
a ee x
SS
Adaptation to Light. 29
mulberry, and hazelnut and compare them with Figure 33.
This is the simplest of all leaf-arrangements. There are two
leaves in one round; the leaves are 180 degrees apart and
there are two vertical rows on the stem. Notice now that
the arrangement of the branches is the same on those trees;
notice that the bud-arrangement is the same; that buds and
Ltranches are alike just above leaves; this pcesition of the
Fig. 37. Fig. 38.
Fig. 37. A thirteen-ranked pine cone. After Gray.
Fig. 38. A five-ranked tamarack cone. After Gray.
branches can be seen more easily on some branching annual
like the clematis or ragweed.
_ Leaves, then, have positions in which they grow; so have
buds and branches; this has reduced the study of disguised
leaf forms to a science instead of a notion. Position is the
determining element. It is important for the student to
learn this.
30 Nature Study.
Exercise II. Get short, straight, young branches of
birch and also some of the tall, rough, triangular sedge
grasses; cut these off very close to the ground and examine
Fig. 39.
A cabbage-palm—Melbourne, Fla.
the sheathing leaves at the base. Compare their leaf-ar-
rangement with Figure 34. Notice that there are three
leaves in a round, that any two consecutive leaves are
therefore one-third of 360 degrees, or 120 degrees apart.
This will be much more difficult than exercise I. If you
ee
Adaptation to Light. 31
fail try exercises III, IV and V first and then return to II.
Exercise III. Get straight water sprouts of peach,
cherry, plum and quince and cones of the larch and tama-
rack. Compare them with Figures 35, 36 and 38. Passa
string as shown in the cut. Notice that the sixth leaf is
over the first; that the string to reach the sixth must pass
twice around the stem. There are then five leaves in two
rounds; or the consecutive leaves are 2-5 of 360 degrees,
that is 144 degrees apart.
Exercise IV. Get similar branches of hedge, holly and
plantain and compare them with Figure 11, and make cal-
culations as before. How many rounds does the thread
make before reaching the leaf directly over the first? How
many leaves does it pass? What is the angular distance
between consecutive leaves? How many vertical rows are
there on the stem?
Exercise V. Get a cone of white pine and make out the
arrangement in Figure 37 and make calculations as before.
Answer the questions for the white pine given at the close
of Exercise IV.
Notice that all these different leaf-arrangements are so
many ways plants have to accomplish the one purpose of
getting their leaves to the light. Figure 39 is a cabbage-
palm. What has its trunk to do with getting its leaves to
the light? The long petioles of the leaves? The arrange-
ment of the leaves? The frayed out ends of the leaves?
“Next to moisture, light is the most powerful external
factor in giving shape to plants. Warmth sets the machin-
ery of the plant in motion and regulates in the highest de-
gree its development and activity but does not affect form.
Light, as also water, exerts a commanding architectonic
influence in the upbuilding of the plant body.’”’—Schimper.
Plant Geography as Influenced by Light.
32 Nature. Study.
LESSON XVII.
Pollination.
Self- Pollination.
Figures 40 and 45 show flowers
with sepals, petals, stamens and
pistils. In Figure 40 the stig-
mas are recurved and at the
center. Every one has seen the
t owder, often yellow, which the
stamens bear. Figure 41 and
42 show photographs of some of
this dust taken with a micro-
Fig. 4v. scope; the figures show the grains
A complete flower; three sepals, °
the smaller outér leaves; three Many times as large as they
petals, the longer inner leaves; six
stamens and a pistil of three united really are.
sees Tee en rea These grains of powder are called
pollen. It has often been shown that plants will not bear
seeds unless this pollen falls on the stigma of the pistil.
This process 1s called pollination. Figure 41 shows 2 pollen-
grain, the wall of which has opened and the co itents of
which are growing down through the top of the style toward
the ovary.It does notcease to grow Ccwn untilit reaches the
ege-cell of the ovary when one of the pollen nuclei unites.
with the egg-cell and fertilization is complete. When the
stamens that furnish the pollen grow in the same flower
with the stigma on which they fall, we call the process self-
pollination. When the stamens grow in one flower and the
stigma on which their pollen falls g-ows in another flower,
we call the process cross-pollination. Flowers which have
both stamens and pistils are perfect flowers.
Exercise: Find a half dozen kinds of flowers that are per-
fect. Count the stamens and stigmas in each so as to b>
Pollination. 33
Fig. 41.
Two pollen-grains that have alighted on a stigma of purslane; their pollen-
tubes are growing down toward the egg-cell in the ovary. From a slide by Mr.
Vivian Floyd. x 300.
sure the flower has both and sketch them, showing just the
right number.
LESSON XVIII.
Pollination.
Staminate and Pistillate Flowers. A Monoecious Species.
If a flower contains stamens but no pistils, we callita
staminate or sterile flower. There are many such flowers in
34 Nature Study.
a single tassel of corn. If a flower contains pistils but no
stamens we call it a pistillate or fertile flower. The silks
that corn bears where the ear is to be, are parts of fertile
flowers.
We name all those plants that we think sufficiently re-
Fig. 42.
Pollen-grains of white pine with an air balloon at each end. x by about 400.
semble each other to have descended from a single seed or
from common parents, a species. Corn, the marsh-mari-
gold and the red maple are examples of species. When the
‘staminate flowers grow on one part of a plant and the pis-
tillate on another, as in the case of corn, we call the species
a monoecious species. When the stamens grow on one
plant and the stigmas on which the pollen falls grow on
Pollination. a5)
another, we have cross-pollination, in which different 1n-
dividuals take part as well as different flowers. Yellow and
white corn will, as is well known, mix across a road; this is
because pollen from the tassels, the stamen bearing flowers
of one kind, falls on the stigmas of the other kind. It is
said that it will not do to plant watermelons and pumpkins
in the same patch; the pollen from the pumpkin blossoms
will get on the stigmas of the watermelon blossoms and the
melons will be ruined. Broomcorn and cane cannot, for
similar reasons, be raised near each other. These are cases
of cross-pollination between different species. Cross-polli-
nation between individuals of the same species seems to
result in stronger plants. Many experiments have been
tried that show this; see Lesson XXVIII. We would be
justified in concluding that it is so because nature has
taken such pains to bring cross-pollination to pass. 7
LESSON XIX.
Pollination.
The Advantage which the Monoectous Species Has.
The tassels containing many staminate flowers grow on
the top of the corn stalk; the chances are that the pollen will
be carried by the wind obliquely and that it will reach the
pistil of some other stalk and so produce cross-pollination
between flowers of two individuals. If the pollen grew in
the same flower with the silks this would be far less probable.
It may be said that the monoecious arrangement favors
cross-pollination from plant to plant and is therefore a help.
_The ragweed furnishes another fine illustration of this.
The sterile flowers grow in long racemes at the top of the
weed. It is a habit some boys have to scrape up between
JOP. Nature Study. |
their fingers the yellow dust and its receptacles from the
sterile flowers. Where do the fertile flowers and seeds of
the ragweed grow? At least they grow somewhere lower
on the weed than the sterile flowers do. The wind carries
the pollen everywhere and doubtless effects cross-pollina-
tion from plant to plant generally.
LESSON XX
Pollination.
The Dioectous Species.
It often happens, as in the case of the mulberry, shame
of the trees do not bear seeds. This may be because one
tree bears only pistillate flowers and the other only stami- ~
nate flowers. The first kind is said to be a fertile, pistillate
or female tree, the second a sterile, staminate or male tree.
A pistillate tree will only bear when there is a staminate
tree somewhere near enough to send pollen to its stigmas.
Exercise: Find a mulberry tree that bears and see how
far it is to a pollen bearing tree. It would manifestly aid
the wind in bearing the pollen long distances if the pollen-
grains were winged. This is often the case. Figure 42
shows the winged pollen-grains of white pine.
Herodotus makes note of the fact that the Egyptians had
a yearly festival, in which they went to the desert and
brought sterile palm branches and waved them over the
fertile trees they had planted along the Nile. By this
means they could give all their space to the growing of trees
that would bear: It would be interesting to know how they
came by the knowledge that such action would cause fruit
to grow, long before we knew the office of pollen in fruit
production.
Exercise: See if box-elder is a dioecious species. Is red
:
:
|
Pollination. Sch
Cedar? Is Ailanthus? Is the Persimmon? Is any willow
you know?
The plain advantage of the dioecious arrangement is that
cross-pollination is the only kind that can occur; but it
seems to be a law that every advantage has its accompany-
ing disadvantage; the disadvantage in this case is that only
part of the trees can bear fruit.
LESSON XXI.
Pollination.
Flowers in which the Psitil Appears First.
Common plantain is a weed every one knows; it has a
rosette of tough broad leaves from which it sends up a long
spike of flowers. This spike blooms from the bottom up.
In any given flower the pistils ripen before the stamens do;
it is therefore entirely impossible that any stigma should
receive pollen from a stamenin the same flower. Protogyny
is the term we use to describe this arrangement; the word
means pistils blooming first. This is one of many ways by
which nature provides for cross-pollination. If the lowest
flowers on any stalk are fertilized at all it must be with pol-
len from another plant; it 1s often coubtless true that higher
stigmas receive pollen from other plants. That the ripe
pistils are above the ripe stamens favors this. The growth
of the plants in societies also favors it.
Some species of plantain may be found blooming all
summer long. Sketch a spike when the ascending circle of
protruding stigmas has reached the middle of the stalk with
the circle of stamens below it.
38 Nature Study.
LESSON XXII.
Pollination.
Flowers in which the Anthers Appear Furst.
The fireweed, Epilobium, is not so common as the plan-
tain. I have, however, seen it blooming in many parts of
the country, late in August. Its time for blooming is given
from July to September. It has a pink-shaped blossom
with a reddish-purple color. It is some four feet high and
very striking. Its anthers come out first, the stigma being
bent quite out of the way, and discharge their pollen and
wither; the pistil now becomes erect; the anthers of its own
blossom having withered, only cross-pollination can occur;
bees carry pollen from one flower to another and thus pro-
duce cross-pollination.
Fig. 43, after Gray,
Wee 22 shows the ripe stamens
and the recurved, un-
ripe stigma. Figure 44,
Fig. 43. Fig. 44. also after Gray, shows
Fig. 43. Fireweed blossom, stigma green and the erect ripe stigma
recurved, stamens ripe. Fig. 44. Fireweed; stig-
ma ripe and erect; stamens withered. After Gray. and withered stamens
Figure 45 shows two blossoms of Amaryllis. The one on
the right has ripe stigmas and withered stamens; the one
on the left unripe, recurved stigmas and ripe stamens.
Notice the white stigma quite below the anthers in front of
a petal. Notice that it is not divided. Nine days later
when its own stamens were wholly withered it had bent up
to about their position so that an entering insect would
brush it and its three stigmas were fully ripe and unfolded.
The stamens being now mature in the left blossom are in a
position to be brushed by an entering insect.
Pollination. 39
Fig. 45.
Two blossoms of Amaryllis; the stamens and pistils show the same thing as
Figures 43 and 44.
40 Nature Study.
LESSON Oc,
Pollination.
Flowers and Insects. Bees.
A fine beginning of the study of this relationship can be
had by the careful study of the parts of a bean blossom;
after which the visits of the bees to the blossoms must be
, watched. The wings of
the bean blossom (1),Fig-
j-7 ure 46, furnish a landing
j place for the bee; image:
Fig. 46. ewe land here in order to get
Fig. 46. A bean blossom; 1, the wings on the honey. The style,
which the bee lights. 2, the keel in which
are the stamens and pistil. After Gray. 5
' Fig. 47. Bean blossom. The weight of the stigma and stamens are
bee on the wings causes the stigma 1, and /
the hairy, pollen-laden style 2, to come out enclosed in the keel. The
of the keel. The stigmastrikes the bee and picks -
up pollen from another flower. The blow stamens early shed their
males Sig oun, pollen toll om the stvic-en pollen which lodgesaaas
Gray. hairy style near the stig-
ma, Figure 47. The weight of the bee on the wings presses
the style and stigma out in such a manner that the stigma
picks up pollen from the bee’s body that came from another
flower and at the same time the style scatters down oa
the bee its pollen to be carried to the stigma of the flower
next visited.
Exercise: Press down on the wings of the bean blossom
where the bee must light and watch the naked stigma and
pollen-laden style come out. Cipher out the entire machin-
ery and watch the bee’s visit.
GLEICH UND GLEICH.
“Ein Blumenglokchen A tiny hare bell
Vom Boden hervor, In the meadow grew up
War fruh gesprosset And hung out enchanting
In lieblichem Flor; Tts little, olue cup;
Dan kam ein Bienchen A bee came and sipped
Und naschte fein: Of its sweets caintily;
Die mussen wohl beide They must for each other
Fur einander sein.” Be flower and bee.
GOETHE.
ne
Pollination. At
LESSON XXTV-
Pollination.
Flowers and Insects. Butterflies and Moths.
Adaptations between flowers and insects to produce cross-
pollination are very numerous and common. Some of them
Fig. 48. Fig. 49. eu
Fig. 50.
Fig. 48. Head of a moth. Its long tongue enables it to reach the nectary of
an orchid shown in 2, Figure 50. P
: ollen masses 1, of Figure 50, adhere to the
moth’s eye by the disk; they are thus carried to the flowers subsequently visited.
Fig. 49, the pollen masses by their gravity, turn down so as to reach the stigmas
of flowers later visited. After Gray.
Fig. 50. An orchid blossom, after Gray. Its pollen mass adheres to the moth’s
eye by a glutinous disk, 1, while the moth is getting nectar.
are very complex andinteresting, as, for instance, the lady’s-
slipper, which will only let a bee out of the “‘slipper”’ along a
road that forces it to rub first against the stigma and pollin-
42 Nature Study.
ate it and then against the stamens and gather pollen for the
next flower. The relations between certain other orchids
and moths are as remarkable.
Figure 50 shows one of the orchids. The nectar is at the —
bottom of the long spur 2. The moth’s tongue is just the
instrument to reach it there. The opening into the nectary
is so small that ants cannot enter; this is the case with many
flowers; ants have no wings; they cannot fly from flower to
flower and carry pollen for cross-pollination; it is therefore
as necessary to keep ants out in some way as it is to attract
bees, butterflies and moths. |
Notice the flower again; at 1 there is a glutinous disk that
carries many pollen-grains on a long stalk. These two disks
are so situated that when the moth is taking nectar they will
touch and adhere to its eyes as shown in Figure 48. Gravity
then pulls them around to the position shown in Figure 49.
When the moth visits succeeding flowers these will be
thrust down to the concealed stigmas and cross-pollination
will take place. Coordination 1s common between the vari-
ous parts of one animal or plant, as for instance the tiger’s
claws and teeth go with the savage disposition; but here
moth and flower fit each other like the nose and the specta-
cles. How came this fitness to pass? The way to study
this question is to notice from year to year carefully all
similar relationships and see if they do not finally fall into
a system.
LESSON XXV.
Pollination.
Symbtosis.—‘‘ Reciprocity.”
Bees get pollen and nectar for the hive from the flowers.
Pollination. 43
Flowers get the inestimable advantages of cross-pollination
from the bees. The relationship is one of mutual helpful-
ness. Symbiosis means life together. Butterflies and
moths get nectar and pay for it with service in cross-polli-
nation. The world of life is full of instances like this.
The raspberry and cherry feed the bird and the bird plants
their seeds in distant soils. The kingfisher digs the hole in
Fig. 51.
A cross-section of lichen, showing its come upper and lower layers to prevent
drying out; its inner reservoirs for moisture, 1, and the symbiont within 2, the
round, black cells. Their real color is green.
the bank and the bumble-bee has been known to occupy it
with him and keep the small boys and other enemies away.
The rattlesnake and the prairie-dog sometimes live together
for similar reasons. The lichen has imprisoned a green
plant between its leathery exteriors. The lichen holds the
green plant up to the light, gives it support and protects
it from the drought on rock or tree, while the green plant
gathers food for both.
Exercise: Cut a lichen in two with a sharp knife or razor
4+ Nature Study.
and notice the green strip between the two white ones.
Figure 51 1s a photograph of a cross-section of a lichen and
its imprisoned alga. The alga has been taken from the
lichen and reared separately ; so it is an independent plant.
What is the relationship between man and the domestic
animals and plants? That is,
are man and corn mutually
helpful? Are men and horses?
Fig. 52.
Cyclamen blossoms. The flower nods
and the floral envelopes turn back up
in such a manner that the entrance of
ants or rain into the blossom is impos-
sible. The lines in the petals shown
in the blossom to the right were caused
by eosin absorption.
LESSON: XXxavae
Pollination.
Flowers and Insects. How the
Anis Are Kept Out.
One common way is given
in Lesson XXIV. There are
several other ways; the plant
is sometimes surrounded by
a water cup,—the teazel is
anexample. It sometimes is
covered with bristly, down-
ward pointing hairs in some
part; sometimes these hairs
are sticky and imipedemes
even catch the ant; some-
times the plants are slick and
the ant, in her efforts to stick
on, pierces the skin of the
plant and a viscid juice turns
her back or catches her;
sometimes the flowers are
nodding and she can’t crawi
down to the edge of the cor-
olla or calyx limb and safely
turn and craw] back up to
the nectar; sometimes the nectar is shut in and the door will
Pollination. 45
not open except to the knock of the friendly bee.
Exercise: Be on the watch for all these methods of ar-
resting the ant. Seeif you can find a smartweed that grows
both on land and in water, having a water cup to keep ants
away when it grows out of the water, which it leaves off
when it grows in water. Read chapter III of Sir John
Lubbock's ‘‘Ants, Bees and Wasps.”’
LESSON XXVII.
Pollination.
Flowers That Never Open.
Pollination sometimes occurs in a closed flower. This
must always be self-pollination. The anthers that furnish
the pollen and the stigma on which it lodges must belong
to the same flower.
Exercise: In the spring,
examine every sort of violet
that you can find, especi-
ally those that seem to
have no stems; you will
find a second kind of blos-
som concealed by the leaves
hard to find, but which
| bears nevertheless, more
| seeds than the flowers you
| have always known, Figure
53. These blossoms never
| open. There are flowers
belonging to sixty different
genera that are self-polli-
nated without opening.
Cleistogamy is the name
given to self-pollination in
closed flowers.
Fig. 53.
A violet plant dug in December.
Large pods of cleistogamic flowers, 2, and
pods of other ordinary flowers opened, 1.
£015 Nature Study.
Some of the advantages of cleistogamy are: 1. Pollina-
tion is sure to occur. 2. Itis not necessary for the flower
to provide so much pollen. A cleistogamic flower grows
some 400 grains of pollen; flowers which depend on insects
to carry their pollen produce many times 400 and other
kinds of plants yet to be described, see Lesson XXX, so
many that the number can be estimated, not understood.
Here, as elsewhere, advantage and disadvantage are bal-
anced. The cleistogamic plants are weak. It is believed
that they lack a factor that is necessary to their higher
development. For some unknown reason, copulating cells
from individuals of a species diverse in their origin give a
strength and variety not otherwise to be had. Many sim-
ple plants and animals reproduce by division of the parent;
but these do not improve; they live on and on at one dead
level. Some eggs will grow into new individuals without
fertilization; we call the process parthenogenesis, but the
parthenogenetic species does not improve from generation
to generation. A capital exercise for any one provided
with a microscope would be, to estimate the number of
pollen-grains in a cleistogamic flower of violet, an anemo-
philous flower like pine and an entomophilous flower like
clover.
ARSSOIN SOC WARE
Pollination.
Results of Experiments in Cross and Selj- Pollination Plants
of the Same Species.
Darwin raised 73 morning-glory plants from seeds pro-
duced by cross-pollination and in the very same soil 73
plants from seeds produced by self-pollination; these sets of
73 plants both belonged to ten generations. The height of
the first 73 was to the height of the second 73 as 100 to 77.
So the crossing made stronger plants.
Pollination. 47
His crossed and not crossed plants of the ninth generation
bore seed by weight as 100 to 61. These experiments con-
firm what we should expect from the fact that nature takes
such pains to produce crosses and the further fact that
' crossing actually takes place among all higher plants.
Exercise: Cut the tassels from a few hills of corn before
it ripens so that you can be sure cross-pollination from
plant to plant, must occur. Dust the pollen from its own
tassel on the silks of a few other stalks in the same row
growing close by and see which makes the best corn.
ESSON?: XX LX
Pollination.
Why. Flowers Are Showy. Entomophilous Plants.
The word entomophilous means insect-loving. It is
applied to all those plants that depend on insects to carry
their pollen. Such plants have bright colored flowers.
Examples are red clover, white clover, morning-glory,
hollyhock, snapdragon, Catalpa, etc., all showy flowered
plants, ait pients the tlowers of which attitact general atten-
tion. It is believed that they are showy in order that. the
insects may see them. Why should they provide pollen
and nectar for the insects and then not inform the insects
in some way where they are? The odor of the flower serves
the same purpose; a single flower might grow where the bee
could not see it; in this case the odor alone tells the tale.
We learned in Lesson XX VII that flowers that never open
are inconspicuous. They are so inconspicuous that al-
though they grow on our well known and universally loved
violets, very few people indeed ever saw them. No doubt
it is greatly to the advantage of flowers that do not depend
on insects to help them to be inconspicuous.
48 Nature Study.
Exercise. Keep a list all summer long of the plants you
see visited by insects. See if you can find out how it is
necessary for the insect to become covered with the pollen
and, also, to brush it on the stigmas of the flowers they
afterward visit.
LESSON XXX.
Pollination.
Why Trees Have Not Showy Flowers. Anemophilous Plants.
The word anemophilous means wind-loving. It is applied
to all those plants that depend on the wind to carry their
pollen. This includes most of the forest trees north of the
Ohio river. Most people do not know that our beeches,
oaks, hickories and pines, etc., ever bloom at all, but if we
examine them in the spring we shall find that they produce
countless millions of pollen-grains; enough, so that a single
tree can give them to the wind and fill all the air for long
distances. The trees are tall: they can take advamtageren
the wind as low herbs cannot. It is a considerable tax on a
plant to produce large, showy blossoms. Why should they
do this when they have a perfectly adequate way to get all
done that insects could do?
Exercise: Make a list of anemophilous plants. You
may at first write in this list all plants with inconspicuous
flowers, then notice to see whether bees visit them and if
they do, note this fact. You cannot learn too soon that all
our distinctions and cividing lines are artificial and for our
convenience. You can not help observing, if you look,
that many plants are crossed both by wind and insects and
that self-pollination often occurs by the agency of both
Adaptation to Climate. 49
insects and wind and also in the very same plants without
the agency of either of them. Let apparent inconsistencies
be an incentive to you to look again. Sooner or later you
will find that the sum total of the influence of wind and
insect is to produce cross-pollination.
LESSON XXXII.
Adaptation to Climate.
Storms.
Stand by the window and watch a tree when the fiercest
storm is on; see how trunk and branches and leaves, if there
are any, yield to the storm. Where is the strain greatest?
Is it not just at the ground? And yet is not this just the
place where a sound tree never breaks? Did you ever try
to splita stump? When the sound tree must fall does it not
always break a few feet above the ground or else blow up
by the roots? How does it come that the strongest place
in a tree is the place of greatest strain and danger? Watch
a very small tree, only two or three years old, in a storm.
Does it not yield to the strain, even to the extent of bending
over to the earth sometimes? Would this not have a
tendency to twist the grain at the ground and make the
grown tree stronger there? The storm then strengthens
most where it threatens most.
Try to split a tree that has grown for a long time on the
edge of a forest on the windward side and another that has
grown in the middle of the forest; which splits the more
easily? Why?
In parts of Europe, large areas are plantedin trees. Hills
and mountains are kept covered in this way by forests. As
one ascends the Brocken he sees every few hundred feet, a
50 Nature Study.
small, fenced area. Trees are being sprouted in these to ke
planted out subsequently at the same altitude. They are
raised from the start, subject to the same tempests, rairs
and temperature that will surround them when they are
trees; and in the same kind of soil.
IE SSOUNE SOOO,
Adaptation to Climate.
Annual Herbs.
In the northern United States, the growing season is
practically between March and November. During the
winter the temperature may fall to 20 degrees or more below
zero. Most indigenous plants have habits which especialy
adapt them to this. Consider a tender herb like the rag-
weed; as winter approaches, it must cover itself with a cloth-
ing that can resist this cold and the accompanying wet, or
die. J presume most of us think 11 dies, but thanwicumer
quite the case. It selects a small part of itself which we
call the seed, to which it gives a covering adequate to with-
stand all the exigencies of winter and keep the embryo
within alive. To have protected its entire body or even
the main part of 1t would have been very expensive and,
although some plants do this, if all plants did 1t we would
have to have far fewer plants for there would not be room
for them in the world.
One way then to meet the conditions of winter is to reduce
life to the compass of the embryo and wrap it up securely
with the food necessary to start it in the spring.
The beans we eat, the corn, the wheat, contain an embryo
in every grain. Every one of them is a plant reduced to
its winter condition.
Exercise: Make a list of fifty plants that live through
Adaptation to Climate. sul
the winter in their seeds only. In making this list, you
must know from careful examination that the root as well
as the top, dies. While this is true of the mullein or thistle
that bears seed, it is not true of all mulleins or thistles.
LESSON XXXIII.
Adaptation to Climate.
Bienmal Herbs.
A biennial plant is a plant that lives for two years only;
that requires two years to bear seed. The root in all cases
survives the first winter and the seed the second. The
thistle, mullein, dandelion, turnip and cabbage are examples.
The mullein does not grow a long stem the first year. This
is an adaptation to the winter it must pass. It grows flat
on the ground, Figure 28, and has a thick covering of
branched hairs. These may serve to temper the light of
the sun; to hold dampness away from the surface of the leaf
so that when it freezes it makes a cloak to keep the leaf
warmer than it would be if naked, to check transpiration,
or to protect the mullein from enemies that would otherwise
eat it. The chief adaptations of the wild biennials like the
mutlein and thistle, to climate are that they grow only a
short stem the first year, and they shrink to the dimensions
of seeds the second.
Exercise: Make a list of biennial herbs. Watch marked
plants and see that they die when they seed at the end of
the second year. Figure 54 shows a two-year-old mullein
aesceamme time, | Compare it, with Pigure 23.
On
bo
Nature Study.
Fig. 54.
A two-year-old seed-bearing mullein. Photographed by Prof. J. F. Thompson.
Adaptation to Climate. 53
LESSON XXXIV.
Adaptation to Climate.
Perenmial Herbs. Solomon’s-Seal.
You must know this interesting plant if you do not.
Figure 55 shows the underground stem with its peculiar
seals, the places where the plant grew in previous years, and
a terminal bud. The seals mark the place from which the
Rig. 5.
Underground stem of Solomon’s-seal. The scars or “‘seals’’ are shown above
where the above-ground stem grew one, two, three and four years ago.
aerial stem broke off last year and for the three years before.
The root-stock is dying at the left. Its adaptation to win-
ter manifestly is that it dies down to the ground at its
approach and lives only in its underground stem and its
seeds.
Exercise: Make as long a list as you can of plants in
your vicinity that live through the winter by dying down
54 Nature Study.
to the ground only; it may help a little to ask, do ferns do
this? Does bloodroot do it? Does blue-grass?
LESSON XXXV.
Adaptation to Climate.
Deciduous Forests.
The falling of the leaves in autumn is one of nature’s
great phenomena. To one born in the tropics, where verd-
Fig. 56.
A cross-section of a deciduous leaf, a fern leaf; a stoma is shown open below.
All the cells between the two layers of epidermis are working cells as their chloro-
phyll granules show. x by about 200.
ure is perennial, nothing is more striking. We are used to
it and the strange thing for us would be for them not to fall.
Adaptation to Climate. 55
The falling of the leaves is a preparation for, an adaptation
to winter.
Two choices are open to a tree: one is to so cloak its leaf
surface that it can resist the cold of winter; the other is to
shed its leaves. Each plan has its advantages and disad-
vantages; each has been followed by successful species.
The sycamore saves itself the trouble and expense of pro-
tecting its leaves by shedding them; but when spring comes,
it must spend many days of its precious time in getting its
leaves back again ready for work. Figure 56 is a cross-
section of a leaf that perishes as winter approaches; notice
how thin is the outside protecting envelope. One of the
stomata for admitting air is shown, open below. All the
cells between the upper and lower layer are working cells.
They are supplied with sap by means of the leaf’s veins, one
of which is shown near the middle of the section.
Exercise: Collect a half dozen different kinds of ever-
green and as many deciduous leaves and see which will tear
the easier.
LESSON XXXVI.
Adaptation to Climate.
Evergreen Leaves.
The pine has taken the second plan, mentioned in the last
lesson: it protects its working cells. Notice again, how
tough its leaves are. Find out anew that its outside cover-
ing is tougher than that of the leaves of deciduous trees.
Figure 57 is a cross-section of the half of a leaf of the Scotch
pine. Youcan tell this tree because it has reddish branches;
it has leaves about three inches long and two in a bundle.
Its leaves are covered with a white powdery substance and
have a grayish green appearance. Notice how thick are the
56 Nature Study.
walls of the outside row of cells and also of the cells next to
it except in the places where the leaf mouths for the ad-
mission of air are. Notice that this second layer is three
cells thick at the corners. It would be difficult to find any-
thing more remarkable in its adaptations, its fitness, than
the pine leafis. The cells from the protecting outside layers
Fig. 57.
A cross-section of pine leaf. It shows from without in, 1, a thick walled epider-
mis; 2, a thick walled hypodermis, both pierced by the stomata; 3, chlorophyll-
bearing cells, to be known by their infolded wals. They contain a resin duct,
near the corner; a chain of bundle-sheath cells, 5, surrounding a fibro-vascular
bundle. x by about 100.
to the large empty row, the bundle-sheath, are working
cells; they contain the green of the leaf, called chlorophyll.
These green granules require surface positions on the cell
wall in order to work. The cells have their walls infolded
to increase the surface to which the chlorophyll granules
Adapiaiion to Climate. 57
may cling. These cells of the pine are packed very close
together in pavements one aktove another throughout the
length of the leaf, with a slight space between for air, in
Fig. 58.
An evergreen forest.
order to save space, so precious because it must be protected,
at such cost to the tree. Figure 58 shows an evergreen
forest. It and Figure 3 are December pictures; the one a
Florida and the other an Indiana landscape.
LESSON XXXVII.
Adaptation to Climate.
Buds.
It seems to us that buds, as we see them in winter, are
necessary to trees; that they are to be expected; a matter of
58 Nature Study.
course ; so they are in our climate; the tender, growing points
of a tree must be protected against the rigors of winter.
There is no reason for such buds, and there are none, where
there is little or no change of climate.
Fig. 59. Fig. 60. Fig. 61. Fig. 62. Fig. 63.
Fig. 59. Apple buds, five-ranked. Fig. 60. Large, well protected hickory buds.
Fig. 61. Lilac buds; scales opposite; this is well shown in 61a. Fig. 62. Buckeye
buds. Fig. 63. Beech buds.
Exercise: Gather some large buds from hickory, buckeye
or horse-chestnuts; count the scales that protect the living
Patise yeatieyeMete hairs in the bud to add to the warmth?
Is there a varnish or any other means to prevent the bud
Adaptation to Climate. 59
from getting wet? Gather walnut, beech, lilac and maple
buds. .What difference isthere in arrangement on the stem?
Is it the same as the leaf-arrangement? Where are the buds
of sycamore? Locust? Is there any tree in your vicinity
that conceals its buds under the bark? Consult the ac-
companying Figures, 59 to 63.
An interesting phenomenon one may occasionally see is
due to latent buds. The early buds of willows are some-
times killed in spring by frost; the trees have the power to
produce branches in this case by means of the latent buds;
but considerable time is required to bring them on; so the
willow’s second spring dress comes later than the leafing
out of the forest trees. It is as if it had resolved not to be
caught the second time.
During the winter of 1900-1901, most of the sycamore
buds were killed by the severe cold; in the spring the few
buds that had escaped leafed out and after two weeks or
more latent buds were developed on the other branches and
the two sets of leaves of different sizes could be distinguished
until midsummer.
LESSON XXXVIII.
Adaptation to Climate.
The Persimmon Tree. A Special Case.
Examine carefully several branches on which persimmons
grow and you will find that they grow on branchlets that
have grown the same year. This is greatly to their advan-
tage during winter. Fruit can hardly be killed when it does
not exist. The winter might be so cold as to kill the tree;
but if 1t is not, the branches of the year will grow out and
put out flower buds and flowers and bear fruit. This is a
great advantage and would leave the persimmon quite
ahead in the struggle with frost, only 1t must take also its
60 Nature Study.
disadvantage, which is that a much longer time is necessary
in which to mature its fruit, and so it may be caught by
the frost.
LESSON XXXIX.
Adaptation to Climate.
Influence of the Wind.
Figure (4 shows a Norway spruce. It grew in an open
space where light could be had in all directions. It should
Fig. 64.
Norway spruce; branches longest on the leeward side.
have been as symmetrical as the fir in Figure 4 is. Notice
Adaptation to Climate. 61
that the branches are longer on the right hand side. This
was the northeast side of the tree. To the southwest there
is an open space of several miles; prevailing southwest winds
have thrown the symmetrical light influence out of balance.
They have lessoned growth on the southwest side and
increased it on the northeast side. In many countries the
winds are stronger and they blow much more steadily than
with us; in such places exposed trees lean and stretch their
long limbs in the direction the wind blows in a very striking
Fig. 65.
A live-oak forest leaning from the seaward, windward side. Melbourne, Fla.
View from the south.
manner. Figure 65 shows a live-oak forest near Melbourne,
Florida, every tree of which leans very strongly from the
ocean, the direction from which the prevailing winds come,
Figure 66 shows a single oak from the same forest photo-
graphed from the other side. Neighboring trees made it
impossible to get the entire tree in the picture. That it
leans from something is, however, evident.
62 Nature Study.
Exercise: Find twenty-five exposed trees and see if you
can determine by a study of them that the prevailing winds
Fig. 66.
A single oak of the forest shown in Figure 65. View from the north.
have modified their growth; look in places between forests
that act somewhat funnel-like in directing the wind.
LESSON XL.
The Leaf.
The Foliage Leaf.
The most conspicuous thing inthe plant worldis the green
leaf ,—the foliage leaf, as we callit. A complete foliage leaf
‘The Leaf. 63
has a blade, a petiole, and stipules. Figure 31 shows all
these parts; Figures 24 and 25 show the stipules. when
there is more than one blade, we call the branched leaf com-
pound, Figures 19 and 25. When these are arranged as in
Figures 22 and 25 we call the leaf pinnately compound.
When they are arranged as in Figure 19 we call it palmately
compound. Figures 20 and 21 show leaves pinnately and
_ palmately veined.
Foliage leaves have many different forms: Figures 12 to
27 show a few of them. It is important for us to consider
in the presence of every tree, every plant, how its leaves,
considering form, size, number and arrangement have suc-
cessfully solved the problem of getting to the light. We
must learn to consider green leaves as light traps; they
cannot discharge their most important duty, photosynthe-
sis, without the light. If we cannot understand this duty
now, we need not be too much disturbed; no one fully under-
stands it. See Lessons XCII and XCIII. It is enough for
our purposes now to know that no tree can live without, at
some time of the year, an expanse of green, which in our
latitude, the leaves furnish.
feecneise: Wear to tell trees by their leaves. Begin
with the commonest tree in your neighborhood. Collect,
press, catalogue and draw accurately its leaves. Question
_ yourself about the leaf’s apex, its base, its margin, its lobes,
if it has any, and its leaflets, if it is compound. Is its sur-
face rough? ‘Try the slippery-elm. Is it hairy? Try the
white poplar. Is it smooth? Is it shining? Is the color
the same above and below? Try the silver maple. Is it
petiolate? Has it stipules? Is it thick or thin for a leaf?
Tough or tender? What comparative advantage or dis-
advantage has the tree from every quality of its leaves?
64 Nature Study.
LESSON XLI.
One Duty of Green Leaves.
Figure 67 shows a fresh,
ereen growing end of a
plant which was cut off
obliquely and smoothly
from its stem and thrust
through a card board into
a tumbler of water and
covered with a second dry
tumbler-. TheWeayessnane
given off water which has
collected in droplets in the
upper tumbler. This ac-
tion of the leaf is called
transpiration.
Exercise: Prepare an
apparatus like this and
after some two days try to
form an estimate on seule
Leaves se = moisture. amount of moisture given
Transpiration. off by all the green leaves
of the great forest, or grass covered plain. You must not
think any one can do this accurately with data such as this
experiment alone furnishes, but it is interesting to consider
to how great a thing our experiment points. The air cannot
for many reasons be so dry where forests are as it would be
without them. We must of course, notice that the condi-
tions of our experiment are not those of a growing plant.
Our cutting absorbs from water, not from the soil, with its
varying degrees of moisture; it absorbs through its cut end,
The Leaf. 65
not through roots. The air in the tumbler where the
moisture is given off soon becomes saturated with moisture,
which the air surrounding forests and plains rarely is.
What our experiment shows is the fact of transpiration.
LESSON. XLII.
The Leaf.
Leaves in the Role of Spines.
Leaves sometimes become
spines; we know this because we
find the spines in the position of
leaves or of stipules. We know
it also because we find all de-
grees of transition from leaves to
spines. The leaf of the thistle is
armed with spines. The bar-
berry bush shows all stages in
the transition from leaf to spine, |
Le Figure 68. The locust has a :
~~ pair of spines at the base of its .
leaf in the place of stipules.
The prickly ash shows a similar
modification. The English holly
has spines on its lower leaves;
these continue as high up as a |
cow can reach; above this it has
no spines. Southey writes of
this tree:
— ae
ao
Fig. 68. ‘ “Below, a circling”fence, its leaves are seen’
A barberry spray; leaves become ~ Wrinkled and keen,
thorns. No grazing cattle through their prickly round
Can reach to wound: ]
But as they grow where nothing is to fear,
Smooth and unarm’d the pointless leaves.
?
appear.’ ’
66 Nature Study.
Spines become gradually larger until we at last begin to
call them thorns; but size does not determine; spines do not
become thorns; thorns are modified branches. In the same
way we determine the nature of tendrils, Lesson LI, we can
tell whether we have thorns or spines in a given case. Do
they come off with the bark and have they the position of
leaves? Then they are leaves. The position of a branch or
a permanent union with the wood declares them thorns.
Exercise: Examine haws of all sorts, the honey-locust,
the prickly ash, and determine whether their sharp append-
ages are in the positions of leaves or branches; whether they
come off with the bark or are a part of the wood of the plant.
Prickles such as one finds on the raspberries must not be
confounded with leaf-spines. They are emergencies in the
nature of highly complex and hardened hairs.
LESSON XLIII.
The Leaf.
Leaves in the Role of Bracts.
Notice the leaves of mullein, Figure 54. It will be seen
that they decrease in size from below upward. They finally
become so small that the photograph does not show them.
They are mingled among the flowers all the way to the top
of the stalk. These reduced leaves we call bracts. They
surround dandelions and can be seen reflexed in Figure 88.
A whorl of four surrounds a group of dogwood blossoms. In
this case they are very showy to attract insects. A beauti-
ful blossom in early spring, the liverleaf that grows from a
bunch of last year’s three-lobed leaves has a whorl of three
green bracts so close to the flower we call them sepals some-
The Leaf. 67
times; the only harm that comes from this is, it confuses us
if we are hunting in a key for the name of the plant. No
one can tell every time where bracts leave off and sepals
begin; no more can he tell where leaves stop and bracts
begin.
We will have accomplished the purpose of this lesson
when we see by a study from plants themselves that bracts
are only reduced leaves.
Exercise: Begin with the daisies and find as many
flowers as you can that are surrounded by one or more
whorls of reduced leaves. What is the chaff of oats, wheat,
rye, barley, timothy hay and other grasses? See if they are
not bracts, little leaves in among the flowers.
LESSON XLIV.
The Leaf.
Leaves in the Role of Sepals and Petals.
When a whorl of bracts,—reduced leaves, grows very
close to the flower we change its name and call it a calyx;
and instead of bracts for the separate parts, we say sepals;
sometimes the sepals are green; often they are white, yellow,
etc., and give its color to the flower, in part, just as the
bracts themselves are colored white sometimes, as in dog-
wood. They are sometimes as small as the separate hairs
of the dandelion’s down; again they are larger than ordinary
leaves as in the lily. Position alone determines whether or
not they are sepals. Many flowers have just two whorls of
floral leaves, Figure 40; in this case we call the outside
whorl a calyx and the inside whorl a corolla. The separate
68 Nature Study.
leaves of the corolla are called petals. The sepals and
petals of flowers exist under many disguises; they are grown
together sometimes. One is entirely suppressed sometimes,
in which case we call the one that is left the calyx; the
petals often grow on the sepals; sometimes the petals are
very unlike as in the bean, Figure 46, the snapdragon, and
many other flowers; so are the sepals. You will often have
difficulty in determining which are sepals and which petals.
Do not become discouraged at this; experts have difficulty ;
if you are interested in the naming of flowers you are ready
for a work on systematic botany. Gray’s Manual is a very
good one. Details that would guide you in every case are
too numerous for a book like this to give them.
The purpose of this lesson is to point out that sepals and
petals whatever their shapes or disguises, are modified
leaves. If it seems to you that it is impossible that organs
like the spurs of many flowers can be leaves, two things will
help you: Study spurs in all sorts of spurred and irregular
flowers and see if you cannot arrange a list in which they
become simpler and simpler until they fade out; study a
very complex flower in younger and younger stages until
they are so small you require a lens to see them; are the
flowers more regular as they become younger? Are the
petals and sepals more alike? We apply this term irregular
to flowers that do not have all the separate parts of the
same whorl alike.
The Leaf. 69
BESSON Xx DY.
The Leaf.
Leaves in the Role of Stamens.
We need in this lesson to
know what a stamen is. Fig-
ure 69 shows a complete sta-
(}
y) men at the right: its stem, its
lower part, is called the fila-
; ment; the enlarged upper part
Y is the anther; the anther bears
Fig. 69. the pollen; see Lessons XVII
eee Mar Gay Pecome and XX. Is the stamen a
modified leaf? Students where water-lilies are to be had
are especially fortunate for this lesson. Go to the water-
lily and see if you do not find something like Figure 69.
Here is a gradual transition from a perfect stamen, right
hand figure to a perfect petal, left hand figure. Other
flowers will show the same thing. I have often seen it in
roses. Examine the peony and you will certainly find it.
Exercise: Look at the ends of the innermost petals of
roses for anthers on their tips. Gather some wild roses ;try
to estimate the number of their stamens; compare them
with cultivated roses; have the wild rose stamens become
petals under cultivation? Cultivation (plenty of rich plant
food of the right quality) changes the stamens of many
flowers into petals. This is another reason why we think
stamens are modified petals. It must not be concluded
that in the cultivated flower there is a petal for every stamen
in the wild state and no more.
70 Nature Study.
LESSON XLVI.
The Leaf.
Leaves im the Role of Prstils.
We have seen, Lesson 43,
that leaves gradually
change on the same flower
stalk into bracts; and that
bracts as insensibly become
sepals; sepals in turn be-
come petals which again
may become stamens. We
have also seen that leaves
become spines sometimes
Fig. 70. and we shall see in Lesson
and’ dalage Wat femetions as @ pitche Lf that they pecamameam
ordinary pitcher-plant leaf. drils. In the pitcher-plant
they become pitchers, Figure 70. In a curious plant in
North Carolina leaves become traps 1n which flies are caught.
In many plants leaves become scales. All these organs:
prickles, tendrils, stamens, pitchers, scales, and the highly
specialized foliage leaf itself, are doubtless end results in
the transformations of a common leaf-like form. Spines
would have to go back to or toward this primitive structure
before they could become tendrils or stamens. For the
same reason stamens do not generally become pistils; they
would need to go back in most cases and set out on the new
road which ends in pistils. This is what we should expect,
and it is what we generally find.
Exercise: Look on double flowers of all sorts for pistils
at the center and see if in many instances they have not
become petal-like or even in extreme cases, green leaves
again. Find some if you can that are rolled somewhat pis-
til fashion and with a “‘style-like apex.’”’ Do not be in a
The Lea}. ia
hurry to reach this or any other conclusion to which your
books point. Look often and long and let conclusions grow.
Examine the petalloid stigmas of the common blue flag.
LESSON XLVII.
The Leaf.
Leaves in the Role of Bud-Scales. .
It will be useful to study this lesson in the spring when
the dogwood begins to grow. You will find that growth
from below pushes the scales up and four large petaloid
leaves take the place of the scales of the flower bud. These
were described in Lesson XLIII, and called bracts; the
dogwood thus furnishes us evidence that bracts and scales
are alike modified leaves—the scale in this instance is the
tip of the leafblade; it cannot growand its death produces a
notch in the apex of the dogwood’s bracts. It clings on
for a while, brown, while the bract is white or greenish
white.
It is sometimes the stipules of the leaves that form the
bud-scales. This can be well seen in the forming of new
buds of the magnolia in the fall. It again happens that the
bud-scale is the petiole of the leaf. Ifa sweet buckeye can
be found, its bud-scales will show that they are reduced and
modified petioles because some of them will be tipped with
the remains of the leaflets of its palmately compound leaves.
Another reason why we think bud-scales are modified
leaves, is, the scales are arranged on the buds in the same
order that the leaves are on the stem. Consult Lessons
XV and XVI on leaf-arrangement.
Exercise: First learn Lesson XVI thoroughly so you can
quite understand the two-fifths arrangement; next examine
the arrangement of the petals on a rose or apple blossom
and see if it is not the same; now examine the arrangement
72 Nature Study.
of the scales on rose or apple buds and you will find that the
arrangement is the same. |
Exercise II: Watch the formation of beech and tulip
buds and their openings 1n the spring and see if you can find
any reason why their scales are stipules.
Exercise III: Watch the unfolding of lilac buds in early
spring and you will see every stage of transition from scale
to leaf. See if you can tell by the veining of alae eee—
scale that it 1s a modified leaf-blade. Note especially the
arrangement of leaves on lilac; the leaves are opposite and
“successive pairs are at right angles to each other. Notice
now the arrangement of the bud-scales;isit the same? See
JaEAbERS Oi Bi,
Exercise IV: Examine a spray of atbor-vitae. Its
leaves are reauced o small green scales closely appressed to
the stem; see if there are not two kinds, one on the side and
one on the edge of the flat branch. Examine also a spray
of cedar for leaves reduced to scales. What are the bud-
scales of the Norway maple?
EAS SON Perv anle
The Leaf.
Leaves in the Role of Bulb-Scales.
A white lly bulb will serve us best for this study. Figure
71 shows one taken up in November,—a good time to study
this lesson; any time in Autmn will, however, do. The
scales at the bottom are the bases of leaves in which food
has been stored up to help in making stem, flowers and
seeds the coming year. The leaves which are still green at
the top and still function as foliage leaves, are pale and
thickened at their bases and function as storehouses of food,
—a function of leaves not hitherto noted. Probably there
is no leaf that does not in some part and at some time, hold
some stored food.
The Leaf. 13
Exercise: Cut across an onion; does each of the several
concentric circles you see represent the base of a leaf in
Fig. 71.
A lily bulb; leaves as storehouses for food.
which food is stored? Go for answer to the young growing
onion and see 1f you can trace its leaves to circles in its bulbs.
74 Nature Study.
LESSON XLIX.
The Leaf.
The Pappus of the Dandelion.
Exercise: Get a
dandelion that has
just fully bloomed;
cut the large head
in two from above
downward so as to
split the stem on
which it grows.
Look at the cut
Gea Seen: pees Sekt me half of the large
stamens; 4, pistil. After Gray. iat es head and see if it
is not composed of separate flowers, many of which look like
Figure 72. Compare this part by part with the) simple
flower in Figure 40 and with the separate parts of a spring-
beauty. You will see the same number of separate whorls
in them; sepals, petals, stamens, pistils. Similar parts are
similarly named in the two figures. The outside member of
the dandelion flower is very unlike that of Figure 45, and
of flowers generally, but we have already learned that
position determines; form cannot, for forms are as different
almost as different kinds of flowers. This dandelion down,
then, is a modified calyx. But as we have already learned
that a calyx is a whori of modified leaves we are, therefore,
justified in concluding that the dcwn which we find on the
dandelion seed and which occurs with modifications on
many kinds of blossoms is an extreme modification of leaves,
The Leaf. 75
LESSON L.
The Leaf.
The Blossom End of the Apple.
What are the dead brown appendages at the blossom end
of the apple? They seem to be leaf-like; perhaps they are
the tip of the calyx.
Exercise: When the apple blooms next, examine the
blossom carefully. The parts of the apple are present in
the blossom. Some parts of the blossom are dropped,
some remain and grow greatly. Mark one definite apple
blossom and watch it every day until it becomes a small
apple and you cannot help learning that the calyx closes in
about the pistil and at last fuses with it and then both
thicken together. As the calyx consists of modified
leaves and the pistils of modified leaves it must be that the
edible portion of an apple consists of modified leaves.
You can watch the modification all the way from the leaf
to the apple. .
} Cut an apple across midway
between stem and blossom and
scrape a little from next to the
core; now scrape a little from
next the peeling; which is softer
and. tenderers * See al you can
tell by any appearance where
the outside and inside meet.
compare your cut apple with
Riguce-3., Dhe eaves ~ that
went to make the apple’s pistil
Fig. 73. were wrapped with the upper
A cross-section of apple. Drawn : ‘
by Miss Helen M. Fiske. side in and when the leaves of
the calyx were bent together their upper sides were also in.
76 Nature Study.
In eating the apple then you eat the upper side of the calyx
leaves and the under side of the pistil leaves. Notice care-
fully this figure (Fig. 74) of the upper and under side of a
leaf and see what difference the two sides present. The
upper side at least makes apple pup! that is firmer than the
under. The upper side of the leaf is the compact side; the
lower is the spongy side.
Exercise: Pull some raspberries and blackberries your-
self. Does a portion of the top of the flower stem come off
with the blackberry that stays on with the raspberry?
When we eat a blackberry we are eating a part of the stem
that has become fleshy. Examine the seeds of the black-
Fig. 74.
A section of a leaf. The lower side is spongy. After Gray.
berry and see if the separate seeds are not made on the plan
of a cherry, a stone within and the fleshy part without.
The cherry has no bloom on it when ripe as the apple has;
it is the ripened pistil alone. This pistil leaf has greatly
thickened; the outside which is the under side of the leaf
has become fleshy and the inside which was the upper side
of the leaf has become the hard stone.
Exercise IV: Study walnuts, strawberries and pears
from the first appearance of the flowers until they are fully
formed and see what their several fleshy parts are. Try to
The Leaf. fi
learn what parts of the stem or flower has become tke edible
portion of every fruit you eat.
LESSON LI.
Leaves 1n the Role of Tendrils.
Figure 24 shows us a greenbriar leaf. Its stipules have
abandoned the office of foliage leaves and are entirely given
up to support; they appear as tendrils. Sometimes tendrils
are modified branches. If they grow out from the wood so
as not to strip off with the bark they are modified branches
instead of leaves. Compare the distinctions between
prickles and thorns, Lesson XLII.
Exercise: Find out by this’rule what tendrils are in
erapevines. of
Figure 75 is a leaf of a garden-
pea; notice that in this case the
leaflets of its compound leaf are,
several of them, converted into
tendrils and that its stipules have
grown to the size of leaves to dis-
charge the duties of the green leaf,
which the leaflets have laid down
in order to support the plant. Ex-
amine the sweet pea plant care-
Fig. 75. fully. It has given up its leaflets
ee ee a en form tendrils jalsoy bub instead “of
enlarged stipules for leaf surface, it has expanded append-
ages along its stem; Figure 76.
78 Nature Study.
Another way to tell whether a
tendril is a modified branch or
leaf is by its position. Remem-
ber a branch generally grows
from a bud in the axiom
leaf—that is, from the stem
just above the leaf. Figure 77
shows a tendril of passion flower
in this position. It is, therefore,
a branch, not a leaf.
Exercise: Find some tendril-
bearing plant not here mer-
tioned and ascertain by one or
Fig. 76. the other, or both, of the above
natare te Men Hulen Me baie tules, whether its tene@miamem=
modified leaves or branches.
LESSON LIT.
How Tendrils Behave.
Exercise: Find some tendril-bearing plant and note in
what direction some tendril points that is nearly grown, but
has not yet begun to twine itself about an object. Watchit
every ten minutes for a few hours; does it move around in a
circle or an ellipse? What can it be doing? Is it hunting
for something about which to twine’? Let the tendril itself
answer; bend a twig over so it will just lightly touch the
tendril near its tip and see if it does not stop its movement
in a circle and begin to twine about the twig. How long is
it before the tendril has taken strong hold on its support?
How the Bean Finds its Pole. 79
Examine several
tendrils that have
taken fast hold on
some object and see if
Figure 78 represents
them correctly. What
are the coils between
the plant and its sup-
“port for? . Let “the
tendril again answer;
watch its action in a
storm and see if the
purpose of this can
Bp a, Bie 18. be to yield somewhat
fiegwcil ihe plast nares tothe cuppa? roto the pull of. the
enable it to yield a little in the storm? After ;
Gray. leaves so that it may
not be suddenly snap-
ped off. May it also
be to pull the plant and support closer together?
BESSON LIL,
How the Bean Finds its Pole.
Plant twenty or more twining beans, corn-field beans.
As soon as they come up put poles down for them to climb,
some five inches away and on all sides of the beans. Watch
the beans as they grow and see if they grow up and reach
out in some direction as if hunting something. Mark the
direction in which they point from hour to hour and see if
they swing round in a circle in search of their pole. Do they
grow a little longer and reach a little further every round?
When they have almost reached the pole at a distance of
several inches remove it and see how far the beans can
reach. Of course the same experiment can be tried with
E0 Nature Study.
morning-glories or any other sort of twining plant; it would
be very profitable to try it with several twiners for compara-
tive study. These experiments could be tried on the farm
or in the garden in spring at very little cost of time. Let
the results grow with the season. If the bean fails to find
a pole within supporting distance, does it bend to the
ground, establish a new base and begin to hunt in its new
territory as before?
LESSON LIV.
The Multitude of Plants. The Struggle for Existence.
Count the grains on what you think is an average ear of
corn. I have just found 400 well developed grains on a
single ear. This means that one grain can become 400, in
one year and this 400 can become 400x400 or 160,000 the
second year; and these 160,000x400 or 64,000,000 the third
year; 25,600,000,000 the fourth year. One bushel will
yield as many bushels as one grain will grains; so one bushel
will yield 25,600,000,000 bushels in four years.
The earth’s land surface is 52,500,000 square miles. One
bushel will plant eight acres and eighty bushels will plant
640 acres, or a square mile and to plant the whole earth
would require 52,500,000x80, or 4,200,000,000 bushels.
One bushel of corn would yield enough corn in four years
to plant the whole earth more than six times over.
Read the chapter, ‘‘The Crowd of Animals,” in Jordan
and Kellogg’s ‘““Animal Life.’ 7
Exercise: Estimate the number of beechnuts on a beech
tree and allowing that each tree will begin to bear at thirty
years old and bear at the same rate, how long would it
require for the descendants of one tree to occupy the entire
United States allowing 1,000 square feet to each tree?
Read Chapter III, of Darwin’s “Origin of Species.” Natur-
The Multitude of Plants. 81
alists are agreed that every living species, if its food did not
fail and it had no casualties from climate or enemies, could
in a short time occupy all the available space. This fact
makes the struggle for existence inevitable.
Count the seeds of several plants and the eggs of several
different birds and insects and calculate their rate of in-
crease and see if you cannot verify this conclusion. In this
struggle for existence between plants, every slight help,
every noticeable adaptation is important. A plant that
has some advantages in the scattering of its seeds might
win in this struggle, while other plants without these ad-
vantages, however slight they may seem, might fail. We
are now to study several ways by which seed dispersal is
brought to pass. The, student should not forget while
working out these lessons that he is dealing with one of the
means by which the plant in question has successfully held
its own through the ages in the midst of a multitude of
plants that would have crowded it out if they could; in the
midst of many animals that have lived off of it in part at
least, and in the midst of forces,—heat, light, moisture,
soil, gravity, etc., that have never been considerate of it in
any way.
All the preceding lessons on adaptation to the light, and
all the succeeding lessons on various topics may be profit-
ably considered with reference to the struggle for existence.
Indeed, whatever the book or lesson, if it concerns itself with
any plant or animal it cannot help aiding you in your study
to remember: this species has existed on the earth through
its ancestors from the beginning. What qualities, what
adaptations does it possess that have aided in this long and
successful struggle? No one can fully answer this question
nor does any one know all the conditions that might help
to the answer. The question is not suggested because it is
easy, but because it is important. Because men are work-
82 Nature Study.
ing on it and because it will help any one to interpret what
he sees.
LESSON LV.
Seed Dispersal.
The Wind. ‘Winged Seeds.
Figure 79 shows the fruit
of the linden, often called
linn. This is found hang-
ing on the tree from August
to December.
Gather the fruit when it
is ripe and compare it with
| the figure. Drop it from a
height when the wind is
_ blowing and when there is
, no wind. Why does it
| that the’, leat-like sioner
| , clings to the peduncle for
' half its leneth- aig. siige ges
leaves it at an oblique
een RN) anole, Put ity Conaaenemmm
Fig. 79. see whether it lies flat on
Wing-like bract of linden seed. the ground. Does it lie
In such a manner that the wind can easily get under it to
pick it up and carry it further?
Gather in the autumn a quart of the seed of sugar-maple.
When the wind is blowing, let a boy who volunteers to do
so, sow a hand full from the top of the house. Every one
who sees will be surprised and pleased. Go to the east side,
the leeward side of a maple forest late in the fall and see the
sowing of young maples the wind has effected a quarter of
a mile or more from the trees.
whirl as it falls? sMeieess
Seed Dispersal. 83
LESSON LVI.
Seed Dispersal.
Other Seeds with Wings.
Exercise: Gather as many as you can of the following
tree seeds: ash, hop-tree, Ailanthus, (tree of heaven), water-
beech, ironwood, Catalpa and pine. The pine seeds will be
found in the space just above the spreading scales of the
Fig. 80. Fig. 81. Fig. 82. Fig. 83.
Fig. 84. Fig. 85. Fig. 86.
Fig. 80. Winged seed of water-beech. Fig. 81. Winged seed’of pine. Fig. 82.
_ Winged seed of ash. Fig. 83. Winged seed of tulip. Fig. 84. Winged seed of
maple. Fig. 85. Winged seed of ironwood. Fig. 86. Winged seed of hop-tree.
Drawn from nature by Miss Helen M. Fiske.
two-year-old pine cones. The Catalpa seeds will have to
be taken out of their long bean-like pods. All these seeds
may be gathered in autumn. The seeds of the elm may be
added to this list 1f they are gathered in the early summer
84. Nature Study.
Compare your seeds with Figures 80 to 86. Describe them
in words or sketch them or write out a description of all of
them, giving special attention to the differences between
them. What trees or plants do you know by their seeds?
Increase this number all you can and you will be doing very
valuable nature study.
When these seeds dry, do they warp in such a manner as
not to lie flat on the ground? How does this help them?
In North Carolina a pine forest will very soon thickly cover
an abandoned field. How do the seeds get there? Read
Thoreau’s essay, “Fhe Succession of Forest Trees,’ in
“Excursions.”
LESSON: EVE.
Seed Dispersal.
The Dandelion’s Parachute.
Figure 87 shows many dandelions bearing seeds. Each
seed is provided with a parachute to carry it to some distant
home. You must consult Figure 89 with dandelion seeds in
your hands. How high is the stem that carries these seeds?
Measure it and see if it is not a foot or more. You have
played with these hollow stems many times, making them
into fantastic curls. What are these long stems for? The
dandelion flower bloomed right on the ground, did it not?
The flower was very heavy; it would have taken a much
stronger stem to hold it up than the dandelion has; besides.
the flower is much safer on the ground than it would be a
foot above it, and it can-do its work just as well close to the
ground. But the seeds to be well scattered must be given
to the wind above the grass in which the dandelion grows so:
that it may not catch and entangle them close to the home
blossom, so also that the wind can the better get hold of
them. Weneed not goaway from home for wonders; thereis.
Seed Dispersal. 85
not in all the earth a creature more wisely cared for than
the dandelion that grows at every door.
Fig. 87.
Dandelions in fruit. Photographed by Prof. J. F. Thompson.
“O’er land and sea I traveled wide,
My thought the world could scan,
But wearily I turned and cried
Oh little world of man.
“T wandered by a green woodside
The distance of a rod,
My eyes were opened and I cried
Oh mighty world of God.”
Exercise: Mark a dandelion as soon as it blossoms so
that you cannot mistake it for another. Watch it every
86 Nature Study.
xfi(
Fig. 88. Fig. 89.
Fig. 88. Dandelion plant. Fig. 89. Dandelion seed. Drawn by Miss Helen
M. Fiske.
few hours night and day, and see how quickly when the
right time comes, it shoots up and sends its seeds on their
dandelion mission.
Seea Lispersal. 87
LESSON LVIII.
Seed Dispersal.
Other Pappus-Bearing Seeds.
Figure ,92 is a seed of a thistle; Figure 93 of ironweed ;
Figure 90 of clematis; Figure 91 of milkweed. Compare
them all with the seeds themselves. Find all the seeds you
can that have some kind of hairy arrangement to make them
Wis
Fig. 90. Fig. 91. Fig. 92. Fig. 93.
Fig. 90. Clematis seed. Fig. 91. Milkweed seed. Fig. 92. Thistle seed. Fig
93. Ironweed seed. Drawn by Miss Helen M. Fiske.
light enough for the wind to carry them. Make collections
of these seeds for your home or school in small covered
glasses, jelly glasses will do, all correctly labeled with the
time and place of gathering them and if you know it, the
time of blossoming.
88 Nature Study.
LESSON LIX.
Seed Dispersal.
Some Adaptations of the Thastle.
The thistle has no friends in the world; it has taken care
of itself for so long that it does not expect anything else; it
will be worth while for us to find out how it does this.
Do not try this lesson without thistle seeds that you have
gathered for yourself. Notice how very small the seeds are.
Collect enough seeds of thistle to weigh a grain. Get your
druggist to weigh them for you; break them off from the
hairy balloon before weighing. -Do not think that it makes
no difference how small the seeds are; this is one of the
thistle’s important secrets of success in the world. If the
seeds were larger they could not be sent so far even in its
matchless balloon. You must not think that for thistles or
men there is an advantage without a disadvantage. This
small seed contains all that the thistle that is to be, heirs
from its parent thistle. It will take it a long time to get a
start. Go again to the pasture where you gathered the
seeds and you will see thistle rosettes flat on the ground;
they are one-year-old thistles. They have to work a year
to make up for the small start they had in the world.
Consult Lesson XII on mullein. They are storing food so
they will be able to grow a stalk and bear seeds next year.
Every one knows the thistle is armed with prickles; these
serve to defend it through the two whole years it requires
for maturing its seed.
Exercise: Find in summer the smallest thistle you can.
Mark it so you can’t mistake it and watch its growth from
time to time till it bears seeds the following year.
Seed Dispersal. 89
To learn what its balloon is, see Lesson XLIX.
Read Burns’s poem, ‘‘The Daisy.”’
“The flaunting flowers our gardens yield
High sheltering woods and wa’s maun shield;
But thou beneath the random bield
’ clod or stane,
Adorns the histie stibble field
Unseen, alane.’
LESSON LX.
Seed Dispersal.
Smallness of Seeds and Spores.
As we saw in the last lesson, smallness of seeds has its
advantages. The seed of corn is much larger than that of
the thistle. How much larger? Would you rather I would
tell you or would you prefer to balance them on as delicate
a balance as you can get and find out for yourself?
Because of this good start the corn has in the world, it can
&
eA
Fern rootstock with fertile
and sterile fronds. After Gray.
be planted in May and it will ma-
ture in early autumn. We sow
oats in April and harvest it in July.
Because smallness or largeness of
seed has each its advantage, plants
have carried both to remarkable
extremes.
The fern gains in smallness by
not producing seeds at all, but
spores, which grow in spore cups
collected into little fruit-dots gen-
erally on the under side of the leaf.
These fern-spores are so.small one
can only see them with a micro-
scope. They float in the air as a
~ part of its impalpable dust. They
often light on the perpendicular,
damp, rock wall of a gorge. Here
90 Nature Study.
they grow into small, kidney-shaped bodies, quite unlike
ferns. These bodies bear on the under side rootlets, which
enable them to cling to the rock, and male and fetnale cells
which unite and form embryos. Fern seeds then are not
carried to this apparently inhospitable home, but young
ferns are formed there by a minute cell of the fern, which it
sends out by the wind for this purpose. The fertilized cell
grows at cnce, and so has no need of seed coats for its pro-
tection.
Fig. 95. Fig. 96.
Fig. 97. Fig. 98. Fig. 99.
Fig. 95. Fruit-dots of Figure 94. After Gray. Fig. 96. Cross-section of a
fruit-dot of Figure 94. Fig. 97. Sporangium of Figure 94. After Gray. Fig. 98.
Prothallium bearing archegonia, antheridia and rootlets. After Gray. Fig. 99.
A young fern plant. After Gray.
Exercise: If you cannot learn all this lesson now, you
can see the fruit-dots on the under side of the fern leaf, Fig-
ures 95 and 100. You can visit the greenhouses and see
Seed Dispersal. Q4
Fig. 100.
€ection of fruit-dot and indusium of maiden-hair-fern. x by about 100.
young ferns, prothallia, they are called, the word is plural,
its singular is prothallium, Figure 98; and sometime you can
see through the microscope the sporangium, Figure 97, and
the spores it contains. You can learn also from this lesson
that when you see a plant able to live so extraordinary a
life as the fern does on a rock, it is in some way specially
fitted to its kind of life.
LESSON LXI.
Seed Dispersal.
The Spanish Needle.
We have seen that seeds are variously winged and are
scattered by the wind, Lessons LV and LVI, that they are
borne up by buoyant, hair-like appendages, by means of
which the wind carries them, Lessons LVII and LVIII.
92 Nature Study.
Sometimes they cling by special contrivances with which
they are provided, to men or animals, and are carried long
distances. _The common Spanish needle is one of these,
Figure 101. Notice that the barbs extend away from the
point of the needle, fish-hook-like; they go in easily, but
come out with difficulty. Can any instrument be more
nicely adapted to carry out its purpose than these Spanish
Fig. 101. Fig. 102. Fig. 103. Fig. 104.
Fig. 101. Spanish needle. Fig. 102. Cockle-bur. Fig. 103. Burdock-bur. Fig.
104. Chestnut-bur. Drawn from nature by Miss Fiske.
needle points? How came this weed to be thus provided
for? When you have really seen into a case of fitness like
this, you have as much right as any one to ask this question ;
You had better answer it wrong than not to try to answer
it at all.
Exercise: Collect as many kinds of Spanish needles as
you can. Are these barbed bristle-points in or out as the
seed grows on the stem? How should they be, considering
the interests of the Spanish needle? Do Spanish needles
sink or swim in water? How long will they swim? Do
they have a seed coat that keeps them from becoming soaked
for a considerable time in water? Do they grow in great
abundance in corn fields that are often overflowedby streams?
Seed Dispersal. 93
LESSON LXII.
Seed Dispersal.
Other Seeds that Cling.
Collect cockle-burs, Figure 102, burdock-burs, Figure 103,
sticktights, chestnut burs, Figure 104, bed-straw seeds and
as many other prickly seeds and burs as youcan. You can
get a pocket lens that will magnify five or ten diameters
from the Bausch and Lomb Optical Co., Rochester, N. Y..,
that will greatly help you. Talk over with one another the
differences between these seeds and their adaptations for
sticking. Cockle-burs are very abundant along streams in
my neighborhood, where they overflow their banks; are they
in yours? Answer all the questions for cockle-burs that are
given for Spanish needles in Lesson LXI1, especially the
question, how many days will it swim? How long will it
float in a water current and how far will the current of your
swollen stream carry it in this time?
LESSON LXIII.
Seed Dispersal.
Currents of Water.
It is intimated in Lessons LXI and LXII that Spanish
needles and cockle-burs are distributed by currents of water
as well as by clinging to men and animals. Go along your
nearest stream and get acquainted with as many plants as
you can that grow abundantly and mainly, or altogether
there; do not be discouraged if you cannot name them all,
only be sure that you know them. You will be almost sure
to find the great ragweed.
Exercise: In October gather a quantity of the seeds of
the great ragweed or some other river plant bearing smooth
seeds. Will these seeds float? How long will they float?
How fast does your stream flow in time of flood and how
O4 Nature Study.
far could these seeds be carried before they will sink? When
the seeds have floated as long as they will, will they still
grow if you dry them and plant them? If you try these
things yourselves, you will not need to be told that currents
of water plant seeds in very distant soils. Suppose a new
made island is one hundred miles from land. In how many
ways that you can think of could seeds get there? Could
birds carry them in mud that clings to their feet? Read
“Occasional Means of Distribution” in Chapter XII of the
“Origin of Species.”’
LESSON LXIV.
Seed Dispersal.
Fruit. The Service of Animals that Eat 1.
Crows assemble together sometimes to the number of
200,000 or more and roost through the winter in the same
trees; such a place is called a crow-roost. There is a crow-
roost in Arlington Cemetery near Washington, D. C. In
1889 Mr. Walter B. Barrows collected all the droppings of
the crows from two square feet, and in this material he
found 4,764 seeds of plants brought there by the crows. He
estimates that on the ground of the entrie roost there were
700,000,000 seeds; enough to sow a thousand acres as thickly
as wheat is sown. These were the seeds of stone-fruits, like
cherries, sourgum, sumac, etc. The birds had eaten them
for the fleshy part. The stones had prevented the seed
from being destroyed by the digestive process.
In many parts of our country the mistletoe is found.
It grows on branches of oak, elm and other trees many feet
from the ground. It could not spread if its seed were not
sown in these inaccessible places in some way. ‘The seeds
are gummy and cling to the bills of the birds that are eating
them. The birds then fly away, wipe their bills on the
Seed Dispersal. 95
limbs of distant trees and so plant the seeds where they can
grow. Figure 135 shows a section of an oak branch through
its own wood and that of the mistletoe growing on it. How
are the seeds of raspberries, blackberries, mulberries, wild
cherries, Virginia creepers, etc., dispersed? Next time you
see a bird eating a cherry don’t hurry to throw at it; think
of this vast and mutually beneficent relationship between
plants and birds. The plants feed the birds and the birds
plant the seeds for new plants. Isit not a wise, fair arrange-
ment? Consult Lessons XXV and LXV.
°-LESSON LXV.
Seed Dispersal.
Nuts and Animals.
Have you noticed that walnut trees often grow along
fence rows? They are planted there by some animals, es-
pecially the squirrel; but as he, for some reason, never
returned to claim his hoarded treasure, it has grown into a
tree.
Exercise: What birds or mammals feed on acorns, beech-
nuts, hickory-nuts, chestnuts or hazelnuts? What birds or
other animals hoard them for winter use? All these birds or
other animals sometimes bury or drop them at distances
greater or less from the tree that bore them. Here is our
wise arrangement again; itis wiser than we think. It is not
aftificial. Both parties are vitally interested in maintain-
ing it. In Thoreau’s essay, ““The Succession of Forest
Trees,’ referred to above, Lesson LVI, he shows that in a
neighborhood of oaks and pines, if the pine forest is cut
down, an oak forest will take its place because squirrels,
birds, etc., will carry acorns to the site of the original pinery.
If the oaks are cut down the wind will sow pine seeds where
the oaks had been. Thoreau credits Linnaeus with saying,
“While the swine is rooting for acorns he is planting acorns.”’
96 . Nature Study.
LESSON LXVI.
Seed and Spore Dispersal.
Special Contrivances.
Everyone must know that if you touch one of the ripe
seedpods of a touch-me-not, it bursts with a suddenness and
Fig. 105.
Fern spore-case discharging spores. After Atkinson.
force that send the seeds to considerable distances. The
seed-pods of some other plants do the same thing—as, for
instance, the fireweed, which thus gives its sail-provided
seeds to the breeze.
Spores are sometimes scattered by similar means.
Figure 105 shows a sporangium of fern, greatly magnified.
Spore Dispersal.
97
It will be seen that at the left side in the figure, the cells
change in character; here the adhesion is less than other-
wheres in the outer circle; the contrivance bursts here; when
the cells of the outer ring dry out, their walls tend to collapse
and the outer walls being thinnest, give way and a united
pull is exerted; suddenly the spore-case bursts and scatters
the spores to the wind. a
2
Exercise: Get some stable
manure and put it on wet
blotting paper under a bell-
glass. This compost con-
tains spores of a white mould
that will cover it all over in
two or three days. Gener-
ally after this dies, in about
nine days after the prepara-
tion is set, a mould of smaller
growth comes up, Figure
106. The black cap at the
- top is filled with thousands
Fig. 106.
Fig. 106.
mould that has no common name.
text. Drawn by Miss Fiske. Fig. 107.
Fig. 107.
Pilobolus shooting its spore-case into the
air and scattering spores. Drawn by
Miss Helen M. Fiske.
Pilobolus crystallinus, a
See
of spores too small to be seen
with the naked eye. When
the spores are ripe, the en-
larged portion of the stem
swells out and pulls the part
in the spore cap out forcibly
and suddenly, sending the
cap two feet or more into the
air. The spores are caught
by the wind and scattered
over the grass. Stock eat
them and they pass through
their digestive organs with-
out damage and if they have
warm, wet weather for a few days they grow and ripen again
98 3 Nature Study.
in the droppings of the stock. Everything about their
growth can be seen under a bell-glass, except the spores,
which require a microscope. They will shoot off their little
cannons, hundreds of them and cover the interior of the
bell-glass with their little black caps. Get a high bell-glass
if you can and see how high they can shoot. A curious
thing about the shooting is, the caps always turn over, as
shown in Figure 107, and land on the bell-glass spore-side up.
When this shooting occurs in the open air the caps, on ac-
count of their heavier specific gravity, fall away from the
spores and leave them to be scattered by the wind. |
LESSON LXVII.
Seed Dispersal.
Special Contrivances.
A walnut is round and can roll long distances on a hillside.
Many seeds are rendered conspicuous by being bright
colored. This is true of the seeds of dogwood, black haw,
wild cherry, and of berries and stone-fruits generally.
Black seeds with the snow for a background are especially
conspicuous. This is, of course, to attract the birds and
effect the dissemination of seeds.
Tumbleweeds break off close to the ground; the weeds are
generally roundin shape. The wind starts to roll them and
sometimes heaps them against obstacles in large heaps; as
they roll the seeds are sown over the ground. Figure 108
shows pampas-grass; its tassel shaped tops break off and
are carried in the same way, sowing their seed as they go.
Seed Dispersal. 99
Fig. 108.
Pampas-grass; the tassel tops break off sooner or later one way or ancther and
the wind scatters the seeds.
LESSON LXVIII.
Seed Dispersal.
A Seed Dispersal Table.
Sometimes edible fruits contain seeds the covers of which
are indigestible; these are swallowed by birds and animals
100 Nature Study.
and dropped with their ejecta, Lesson LXIV. Sometimes
as in the case of nuts and grain the seeds eaten are destroyed,
but the plants bear far more than they need and many are
dropped by animals by accident, Lesson LXV. Some seeds
are winged, Lessons LV and LVI; some have hairy append-
ages, Lesson LVIII; some have hooks on the pods, which
contain them, Lesson L XI; some float, Lesson LXIII, and
some have special contrivances, Lessons LX VI, and LX VII.
Exercise: Try to find a plant with no special help for
seed scattering.
Exercise: Fill out the following table for every plant in
your neighborhood as the years go by. :
ort o : ‘ wou 4 '
Ieee [eee] B ee?) 8 5
Tm 009 ™ HO i Ne 4 9
O:n Y ofutrs| ¢ By fe) -
ou Ones “ol On A ‘) =) oO
a 85 PF IS go8| a 7a ae
D al 2A8 a) ag 2 D ers Se
oa o8| d od |\o ‘= aa ao O8
Opel oF oO Oo, ae a) oe or
oPr2Oo| oS 7) OARS ® =o orn
nHeBo| 0,90 nN |4AgaAl DM Hs nN,
Wratten Se eee ate pelle ee : Kao fa tek wee | eee ee est eee ee eee : x
Sour-gum sea se hap FOR Soe cecil Bae cet tl enlace ober ole eel a er
Slippery-elm. 0.02 2 5 os | ce Sec | own noel] oo = ace tke [ce oie cca.y fell te ipl eee
TRIS El tae sae eat a Ped ote Leen | ae Ue tener meee : D eee PRIMES ts ae :
Cockle=bins.2i37 aoe es nila oe | eee en heat ome [eateceaeiee x K “2 ierae sas :
TPouch=ne=-nGt 5 ae ol ee ee | es es cia ee 3
Read Chapter IV in Sir John Lubbock’s “Flowers, Fruiis
and Leaves.”
Plant Socteties. 101
LESSON EX TX:
Plant Societies.
Water Plants.
Exercise: Visit several forests, especially to see if you
find considerable numbers of the same kinds of trees growing
in them. Do you know of a maple forest? a beech forest?
an oak forest? Where can you find many willows, syca-
mores, sassafras, gum or other sorts of trees growing to-
gether? Do you know of a society of lilies, ragweeds,
mallow,. blue-grass, cockle-burs or wild roses anywhere?
A group of similar plants we name a plant society. Figure
110 on St. John’s river, Florida, is a palm society. This
island of palms is known as “‘North Indiana Field.” It is
surrounded by shallow water in which reed societies grow.
Locate as many plant societies within a half mile of the
school-house or your home as you can.
Figure 109 shows four societies: lilies in the foreground,
then reeds; then willows; then deciduous forest trees, oaks.
Why do these plants grow together? What advantages
come to them because they grow together? Do not beina
hurry to answer these questions. Do not think that you or
any one else can fully answer them. You will one day
travel in warmer countries than this; in colder; in dryer; in
higher. There are places in your neighborhood that are
dryer than others; places that have a different soil from
others. The south side of a hill is warmer than the north.
From what you see at home and away you may easily learn
that some plants grow in the water only or in very wet soils.
Nature Study.
102
‘pIeMYIEG PUNOIBIIO] oY} ULOIJ 4Sa1OF YEO UL PUL SMOTIIM ‘Spool ‘SaT]I] 1ayeM MOTIO A
; . ‘601 “31a
*Sotjetoos yueyd nog
Plant Societies. 103
These are called water plants, hydrophites; pond-scum,
stonewort, duckweed, and white and yellow water-lilies are
examples.
Fig. 110.
A palm society and a reed society.
Exercise: See how many different plants you can find
that are free-swimming.
104 Nature Study.
LESSON LXX.
Plant Societies.
Microscopic Plants.
All natural waters, ponds, streams, lakes and the ocean
itself, contain plants and animals so small that singleindivid-
Fig. 111.
Diatom shells. One of J. D. Moeller’s slides, loaned by Bausch and Lomb
Optical Co., and photographed with their one-inch photo-objective. x by about €0_
uals can only be seen by the microscope. This life is called
Plankton. Diatoms, shells of which are shown in Figure
Plant Societies. 105
111, belong here. In all our streams, stones and sticks will
be found covered with a gelatinous, sleek, yellowish-brown
layer; this consists of millions of diatoms; there are also
numberless free-floating forms; their walls are made of the
same material that sand is, —silica. These plants have
died in lakes and bays in past ages in such numbers as to
make rock formations
several feet in thickness
and many square miles in
extent. The shells are
sometimes so small, Fig-
ure 112, that 41,000,000,-
000 can occupy a single
cubic inch. Many kinds
of diatom shells are beau-
tifully sculptured, and
have been much studied
on this account. Thou-
Fig. 112.
sands of different kinds Infusorial earth. These cylindrical di-
: atoms shown from both the side and the end
have been described and are so small that 41,000,000,000 can occupy
one cubic inch. x by about 500.
figured.
Exercise: In March every stone and blade of grass in a
stream near my house is covered with this yellowish-brown
growth to the thickness of half aninch or more. Find this,
pass it through your fingers, and if possible, look at a little
of it under a microscope. The quantity of microscopic life
in a lake or other body of water is important, for it deter-
mines the amount of higher life—fishes, for example, that
it can support.
LESSON LXXI.
Plant Societies.
One Plant Adapted to Live im the Water.
Figure 113 is a view near Syracuse, Ind., in a bay of Tur-
key lake. In the view here shown there were hundreds of
Nature. Study.
106
oye] Aoyiny jo Aeq we ‘euerpuy ‘eye’ osnoerés
“€Li “Sa
"SOlfI]-107e
es Ver dy
Plant Societies. 107
water-lilies. The lake was of varying depth from one to
something like four feet. These large leaves and flowers
grow from rootstocks buried in the mud at the bottom of
the lake in which the food necessary to produce them had
been stored up. In this way the stem is preserved from all
danger. The leaves and flowers all seem to have stems just
long enough to bring them to the top of the water. Pull
Fig. 114.
Surface view of stomata and epidermis of the pie-plant. x about 200.
some of them up or row out to where the water is clear
enough to permit you to see the bottom, and you will find
that they are much longer than long enough to reach the
water’s surface; the extra length of the flexible stem enables
it to bring leaf or flower to the top in varying depths; they
can thus ride on the crests of the highest waves that are
likely to come on the lake. They are buoyed up by air-
cavities that make them lighter than the water. These
108 Nature Study.
cavities serve also to conduct air down to the stem. Figure
115 shows such cavities in a kindred species. Figure 114
shows the stomata of leaves under a high power of the
microscope. It is through these openings that air enters
the leaves. In Lesson XXXV there is a cut of a cross-
section of a stoma. Most leaves have these openings more
numerous on the under side. This is, of course, not possi-
ble for the water-lily ; its stomata are all on the upper side;
an adaptation to its life in the water.
Paneer ees
Sa wcQteee
e, C) 288 Ree, Bins
Sear es etter nibe yee
a
yoda]
SWIOOLYSNuUL _ [OSVIE,,
146 Nature Study.
sewer’s mouth and as far in it as you can see, white stream-
ers that live on the decaying matter contained in the sewer
water.
The mushroom and its allies are degenerate plants. They
are not doing plant duty. If they live on living plants or
animals, we call them parasites. If, like the mushroom,
they live on decaying vegetation, or other dead organic
matter, we call them saprophytes. The mushroom has
chosen the line of least resistance which cannot be chosen
by plant, animal or man, except at the expense of its birth-
right. The oak faced the strenuous life; the mushroom
dodged it. Read the introduction to Hawthorn’s “Scarlet
Metuer,
LESSON XCIII.
Chlorophyll.
The general green color of leaves is due to green granules
in the cells. Figure 56 shows these granules. They are
living bodies; they increase by division just as many low
forms of life do. They are simply colored protoplasm.
Alcohol will extract their color from them after which they
can be stained other colors. The upper side of the leaf is
greener than the lower because, for one reason, these gran-
ules are far more numerous on the upper side. They are so
small that they can be seen with a compound microscope
only. They can be well seen in leaves of moss simply by
mounting the leaves in water. They can, of course, also
be seen in all sections of green leaves or of other green parts
of plants. They are very fantastically shaped in some of
our commonest green pond scums, Figure 140.
The chlorophyll granules are the starch makers. They
sometimes contain so much starch that a solution of iodine
colors them so deeply as to mask their green. Starch is
Chlorophyll. 147
composed of carbon and water. These are in some unknown
way brought together in chlorophyll granules. The carbon
comes from the carbon dioxid of the air. The process is
named from three Greek words, which mean a putting
together in sunlight, photosynthesis. We ought sometime,
to see these little granules, and find out how incalculably,
unthinkably numerous they are in a single tree and to
remember that it 1s to their combined action that the earth’s
organic upbuilding is due.
Fig. 140.
Filaments of Spirogyra getting ready fcr conjugation. The flaments can adapt
themselves to the distance between them by length of tube. x about 1CO.
Exercise: If the following experiment is difficult of per-
formance, nevertheless it will help us to understand how it
is learned that starch is made in the sunlight by the green
leaf. Immerse a leaf from a potted plant, in Shimper’s
solution, see below, at about 2 o'clock p. m., and notice that
it gives a starch color; the leaf should have been all morning
inthe sunshine. Keep the same plant in the dark from one
morning until 2 o’clock the next afternoon and then im
merse a leaf in Shimper’s solution. It will show no starch
148 Nature Study.
at all, or very little. Now take a leaf and darken a spot on
it between two slices of cork, thus, Figure 141, from 10
o'clock until’2 the mexteadeas
~ keeping the plant all the time in
==) the sunshine. Immerse this leaf
<“) as before in Shimper’s solution
and the starch color will show
everywhere except in the spot
covered by the cork, which had
been in the dark.
Fig. 141, Shimper’s solution: Dissolve
grows hee foo Toe 1a 8 grams chloral hydrates aaames
Gor eters Denes of water and add to this 1 cc of
iodine solution; see Lesson LX X XVII for the formula of
this solution.
LESSON XCIV.
Protoplasm.
» Differences Between Animals and Plants.
If one considers a cow and a tree the difference is plain
enough; one is fixed, the other can come and go; one ab-
sorbs liquid and gaseous food only, the other can take solid
food into its body and by processes of its own, reduce it to a
liquid state; one can live on inorganic food alone, that is,
what it gets from the ground, water and air; the other must
live on organic food. The plant utilizes and stores the sun’s
energy; the animals utilize the energy of other animals or
plants. The cow has a specialized nervous system. She
knows, feels and wills. The tree seems to lack these things.
These manifest differences between plant and animal life at
their extremes all vanish as we approach the boundary line
Protoplasm. 149
between them as we consider the more similar forms of both.
Animals generally require organic food, but so also do all
fungi, mushrooms, rust, smuts, mildews and moulds.
Animals generally eat solid food and plants generally do
not, but some plants like Venus’s fly-trap and Drosera can
surround and digest solid food. Plants are generally fixed
to the soil where they grow, but so also are many kinds of
hydroids, corals, sea-fans, etc., and many kinds of plants
move freely at some stages of their lives, as freely as ani-
mals do. It has always been true that naturalists could
not agree as to whether certain forms are animals or plants.
From time to time it is agreed that certain forms hitherto
regarded as belonging to one kingdom, shall be set down as
certainly belonging to the other. It has often been pro-
posed to have three kindgoms, a plant kingdom, an animal
kingdom and a plant-animal kingdom; and this would long
ago have been done but for the fact that it would simply
have multiplied the difficulty by two; it is now impossible
to determine in all cases whether a given form should be
called animal or plant; if three kingdoms were recoginzed
it would be impossible to distinguish animals from plant-
animals and plants from plant-animals. The impossibility
of separating plants and animals except by arbitrary
bounds, is one reason why modern science recognizes the
term Biology, the science of life.
That the animal moves is probably an adaptation to its
food supplv, which is, in general, solids that it must go to
get.
That the plant is fixed is likewise perhaps an adaptation
to the fact that its food-stuffs are liquids and gases that can
and do come to it.
150 Nature Study.
LESSON XCV.
Protoplasm.
The Respiration of Plants.
It was thought for a long time that plants consume car-
bon dioxid in respiration and give off oxygen and that
- animals consume oxygen and give off carbon dioxid. This
is wrong, but it is so nearly like something that is right that
it is hard to correct. Plants retain the ‘carbomtomicasaam
dioxid and give off oxygen during the day time, but they
do not consume the carbon in breathing; they make it into
food on which both they and animals can live; they use it
in their work of photosynthesis. The part of the plant,
however, which lives must consume oxygen. During the
night plants give off carbon dioxid as a result of their breath-
ing just as animals do. During the daytime their breathing
is disguised by the larger work they are carrying forward;
during the day they give off carbon dioxid in respiration,
but consume in photosynthesis more than they give off.
Plants that are not green and cannot therefore do photo-
synthesis give off carbon dioxid all day long just as animals
do. |
Exercise I. Make lime-water by soaking a pint of lime
in two quarts of rain-water a few days. Pour off the clear
lime-water and keep it in a tightly corked bottle. Pour a
little of this water into a test tube or homeopathic vial,
.breathe on it and shake it up and it will turn milky on ac-
count of the carbon dioxid in your breath. Now soak two
ounces of peas by measure, in warm water over night and
place them for twelve hours in a six-ounce bottle, well
corked. Decant the air from this bottle into a little lime-
water as before and shake it; it becomes milky. The
sprouting peas give off carbon dioxid also. |
Protoplasm. 151
Exercise II. To show that chlorophylless plants give off
carbon dioxid, put a growing mushroom in a fruit can, seal
it and after a day try the air of the can with lime-water.
Exercise III. Puta healthly potted plant in a fruit can,
close the can tightly and set it where it is perfectly dark for
twelves hours and test the air in it for carbon dioxid. If
it is not put in the dark, carbon assimilation will disguise
respiration; but the respiration will not be any the less real
because it is disguised.
LESSON XCVI.
Protoplasm.
The Cell.
Among the great achievements of the nineteenth century
is the discovery of protoplasm and the proof of its identity
in animals and plants. Protoplasm has been defined as
“the physical basis of life.’ We can, perhaps, better get
at the fact if we say it is the thing that lives, the only thing.
Protoplasm makes starch and fat, the cell wall in all its
forms and all its varied cell contents. It is a granular,
nearly transparent substance; it can surround a bit of food
and digest it; it can grow and divide so that what was one
individual, becomes two; or what was one cell, becomes two,
Figures 143 and 145. Two separate masses can combine
so that two cells become one. Figure 140 shows two fila-
ments of a common green pond-scum which have grown
passage ways from one to the other through which the con-
tents of two cells can unite; the process is going forward at
the top of Figure 147; it is completed at the bottom of the
same figure. Protoplasm is sensitive to heat and cold, to
an electric current or any sort of bodily contact. It re-
quires food and oxygen to carry on its life processes; it can
work in the dark as well as in the light; indeed most of it
152 Nature Study.
is shut up in the more or less opaque walls of plant or animal
cells and does its work there; it can carry on the processes
of assimilation and excretion. It is contractile; it can
slowly move about from place to place when free or it can
move about within the cell wall that confines it. It can
build cell by cell the oak or the elephant and it is its ac-
tivities that enable all living things to do whatever they can
do. Itcan surround itself with a wall of wood, of phosphate
of lime as in bones, of silica. Goethe, who explained so well
the transformations of the leaf, thought there must be
somewhere a type plant by the modification of which all
plants are made. This type plant, “Urpilanze; siaamne
named it without seeing it, is the typical plant cell. When
he sat in his gardens and talked about them but could not
find them, millions of them clothed his trees from root to
crown, for the green coating on bark and fences in damp
countries and localities often consists almost entirely of
them. Multiply them enough and modify them enough
and the miracle of the vegetable world is all about us; and
cells in the presence of the proper stimuli can be shown to
be able to do this multiplying and modifying.
LESSON XCVII.
How Plants Multiply.
The Asexual Way.
Go first to the strawberry and see the runners, prostrate
stems that grow out along the ground and take root at a
suitable distance from the parent stem. This is one way
that a plant can become two. Figure 142 shows a similar
mode of multiplying in the water hyacinth, a plant found
How Plants Multiply. 153
in abundance on the St. John’s river in Florida. The
petioles of the leaves swell out into large floats (a) and by
their number and arrangement keep the plant upright and
prevent it from sinking. The runner has sent roots down
into the water six inches away from the parent plant.
This plant has so spread over St. John’s river as to seriously
interfere with navigation and the government has made
Fig. 142.
Water hyacinth. See text.
an appropriation for the year 1903 for the purpose of
stamping it out.
Go next to the raspberry, or if you know it, to the walk-
ing-fern; the raspberry bends its tip over to the ground and
the fern its to the rock wall on which it grows and they alike
take root at a distance from the home-plant and one be-
comes two. Cut off a number of limbs from a willow and
plant them along a stream; they will grow into trees. Are
they new trees? Individuals? If they had grown on the
old stem would they have been new trees? Is a tree a
— ee on —— ~
154 Nature Siudy.
colony? Budding consists in taking uninjured buds from
one tree and planting them under the bark of another tree.
Grafting consists in taking little shoots from one tree and
properly planting them in the limbs of another. Suppose
wine-sap, bellflower and five other varities of buds are
planted on the seven limbs of a seedling and grow into
thrifty, fruit-bearing branches; what sort of tree is this? Is
Fig. 143.
Filaments of Nostoc, a blue-green alga in process of cell division. x 400.
it seven trees? Is every bud an individual in the colony
that goes to make up a tree?
There are many one-celled plants that have only this
asexual way of multiplying. Figure 143 is a blue-green
alga that may be found in gutters, often along the street or
damp places in greenhouses; it is called Nostoc. The cells
of the filament here shown are in several stages of division.
How Plants Multiply. 135
Figure 145 shows a
parasite plant that is
often found in sores on
the body; it is often
coughed up by patients
suffering with sores on
their lungs. Several
stages of cell division
can be seen.
Yeast owes its prop-
. erties to a one-celled
Yeast-cells in ne os budding. See plant that lives and
text. x 200. grows in suitable liq-
uids. The yeast-plant has a peculiar way of dividing,
ae Be: *
: e %e*|
e po ee |
: f ee
°
Fig. 145.
Filaments of Streptococcus dividing. The kinship in form of Nostoc and Strepto-
coccus is ore good reason for regarding bacteria as degenerate plants. Highly
magnified.
156 Nature Study.
called budding, Figure 144; a very small bud appears on
one side, which grows until it is as large as the mother-cell.
It is called the daughter-cell; in actively “‘coming”’ yeast it
often happens that a daughter-cell begins to bud before it
separates from its mother. This is true of a grandcaughter
and great granddaughter-cell also before any of them have
let go, so that it is possible to get four or five generations in
one picture.
LESSON XCVIILI.
How Plants Multiply.
The Sexual Way.
Another very different mode of reproduction
is by the union of two cells one of which is
known as the male cell and the other as the
female. Figure 146 shows two exactly similar
plant cells uniting on neutral ground. This is
the simplest possible sexual multiplication.
The new individual formed by their union will
divide many times asexually to form new gen-
erations. In this instance it is not possible to —
-| say which is male and which is female, for both
Fig.146. look and act exactly alike.
Rennes enon Figure 147 shows two cells uniting, but not
by celi union
onyund 4) on neutral territory. The cell contents of all
distinction of cells in the left filament pass entirely through
vigil: the funnel tube to the right filament. Both
cells help to make the connecting tube; they look alike, but
do not act quite alike; there is physiological, but not ana-
How Plants Multiply. 17
tomical, distinction of sex; the left filament is the male
filament. The egg-shaped bodies in the female cells are
|
Cd
a
FA
é
Fig. 147.
Spirogyra. Reproduction by cell union in the home of the female cell; physi-
ological distinction of sex, not anatomical; the flaments look alike. x 200.
new one-celled plants; the parent cell walls will decay and
after a rest these will all grow by division into new fila-
ments of pond-s7um.
Fig. 148.
Oedogonium, a common
green alga attached to sticks
and stones. 1, the small
motile male cell goes to the
large female cell. 2. Ana-
tomical and physiologica
distinction of sex. After
Oltmans.
Nature Study.
Figure 148 shows male and female
organs of a plant in which there is
anatomical, as well as physiological,
distinction of sex; here the female
cell not only stays at home and
awaits the coming of the male, but
it is larger, better fed: and better
housed.
Any number of illustrations could
be added showing progress in dis-
similarity between the male and
female cells. This difference is in
size, the male being the smaller; in
activity the male being the more active; in protective
Fig. 149.
Section through the well-protected, well-fed home of a female cell of Erigenia.
The section is through the micropyle through which the male nucleus enters. Slide
prepared by Mr. Charles H. Frazee. x 100.
Fig. 150.
Cross-section of the summit of a male moss plant. a, an antheridium containing
perm-cells. x 200.
Fig. 151.
The same as Figure 150, with antheridium discharging sperm-cells. x 200.
160 Nature Study.
coverings and mode of nutrition, the female being the better
cared for and better fed. Figure 149 shows the safe and
well lardered house of the female cell of the harbinger-of-
Fig. 152.
Two sperm-cells of moss very highly magniited. After Atkinson.
spring, Erigenia bulbosa. Figure 150 shows the summit of
a male moss stem. (a) is a longitudinal section of an an-
theridium containing sperms.
aS
Fig. 153.
Archegonia of a liverwort, Marchantia;
1, an almost longitudinal section through
the entrance; 2, passes through an egg-
cell. These are ver, similar to the same
organs in moss. x 200
Figure 151 shows an an-
theridium bursting and dis-
charging the sperms. A sim-
ple sperm, when mature, re-
sembles Figure 152.) tie
swims by means of its cilia
into the archegonium of the
female moss head which
closely resembles Figure 153.
It reaches the egg-cell at the
bottom of the archegonium,
and fertilizes it. It will be
seen by these figures that
among mosses the differences
between the egg-cell and the
sperm-cell are very great.
Figure 154 shows at (a)
the fertilized egg-cell of the
harbinger-of-spring.
All higher plants, mosses,
ferns and flowering plants
produce in one way or an-
other and at one time or
another in their life history,
How Plants Multiply. 161
such a fertilized egg-cell, and from this cell new plants
grow.
Fig. 154.
A section of a young plant of Erigenia bulbosa during the resting stage after the
7
egg-cell had been fertilized. Slide prepared by Mr. Charles Frazee. x 750.
Figure 155 shows a young embryo of a smartweed; the
fertilized egg-cell has divided twice so that it now consists
of four cells. Figure 156 shows a stage considerably more
advanced. It is thus by cell division, unequal growth, in
different parts, unequal growth in the cells themselves, and
162 Nature Study.
the development of walls of varying thickness and quality,
that the plant with its organs and tissues is matured.
It is worthy of note that the pistil which houses the female
cell, the macrospore, grows at the center of the receptacle, in
the direct line of the food supply; the stamens always grow
to one side and are accordingly, never so well-fed; they
Fig. 155.
A_young smartweed after the fertilized cell had divided and the two resulting
cells had again divided. Slide prepared by Miss Ruth Trueblood. x 750.
often grow on the sepals or petals or even on the ovary
itself, and must be content not only with a side flow of sap,
but they must share this side flow.
A fine study for any one with a microscope would be to
determine the relative amount of conducting tissue that
leads to a stamen and a pistil. To get the real ratio, these
amounts should then be divided respectively by the number
of pollen-grains the stamens bear and the number of seeds
the pistil can bear.
163
Multiply.
Plants
How
Fig. 156.
Many-celled stage of a young plant of twinleaf.
Frazee.
Charles
Mr.
de prepared by
Sli
x 750,
164 Nature Study.
LESSON XCIX.
Growth from the Cell to the Tree.
Cells have been shown in process of division. Sometimes
they divide in one plane only and we have then a filament
like Figure 143. Sometimes they divide in two planes only
and we have flat plants of varying length and width but
only one cell thick. Some moss leaves, except in the region
of the veins are such structures. Sometimes cells divide in
three planes and then we have figures of varying length,
breadth and thickness like most of the plants we know.
The almost infinite variety of shapes in plants arises from
two causes. First, the cells divide in their different planes
a different number of times, many divisions in one plane,
giving length, fewer in another giving breadth, and fewer
still in the third, giving thickness. Second, the cells them-
selves have three dimensions. They are solid bodies and
they may grow to have very varying dimensions. The
typical plant cell is globular, all its dimensions are the same.
Plant cells vary in their shapes from this typical form so
much that their shapes could not have been conceived of or
believed to be if they had not been seen. The various
accompanying microscopic figures show other cell shapes.
LESSON C.,
Cell Duties in a Many-Celled Plant.
In a one-celled plant its life processes are all carried for-
ward by the one cell. It must breathe; it must assimilate;
it must construct a wall if it has one; it must store up food;
it must contract if it is to have voluntary motion; it must
reproduce. As soon as cell union comes, with a vital union
Cell Duties 1n a Many-Celled Plant. 165
between two or more cells, these duties can be divided out
among many or fewer different cells; a tree, for example, has
protective tissue, the bark, some cells of which do nothing
else; 1t has conductive tissue that distributes sap to all parts.
It has supporting tissues that discharge no other duties than
that of holding the vital parts in position. It has secreting
cells such as produce the milk of the mulberry, the resin of
the pine, the nectar of the flower, etc. It has storage cells
for starch, fats, crystals, etc. It has assimilative tissues
and reproductive and many other sorts. This division of
duties can be but slight in one-celled creatures. It can
only be between different parts of the same cell which is
generally too small to be seen by the naked eye. Cell union
has its advantages and disadvantages. In Nostoc and
other similar filaments each cell is independent except for
purposes of defense and buoyancy. It isa sort of defensive
alliance that leaves every member of the community free
to manage its own internal affairs. The community life in
Spirogyra has for its advantage the extra protection and
support of the common wall. The disadvantage is that
individuals are subject to the accidents of the colony. If
we could study all plants gradatim from the simple one-
celled Protococcus to the oak, we should find very gradual
steps in the formation of what may very fairly be called the
combined trusts that go to make the oak. The root trust
gathers the food containing moisture from the soil and
hands it on; it also holds the oak in place and lends its
reservoirs as storehouses. The plant has so completely
given over these duties to the root that it is dependent on
it for at least two of them. The chlorophyll is a trust for
storing the energy of sunlight, so complete that no other
part of the plant can take its place even partially or tem-
porarily. The great advantage of these combinations is
without question; because all the plants which are large
enough to be seen by the naked eye have adopted them,
166 Nature Study.
and the higher the plant in the life scale the more complete,
numerous, and complex are these combinations. Plant
organization has been long ages in perfecting the division
of labor and the co-ordination of its tissues and organs.
Society's organization may one day be equally just and
pertect.
LESSON. CI.
Young Plants.
Every one has noticed the difference between the green
gosling and the white gander, which it becomes. A chick
does not much resemble a chicken. There is a difference of
like meaning and importance between young and old plants.
Exercise I: Plant cucumber, squash, pumpkin, and
several kinds of muskmelon and watermelon seeds. As
soon as they come up, if you see any remains of the seeds,
remove them and try to tell by the young plants what each
one is. Try when they have only two leaves; try again
when they bear four leaves. Watch them as they grow.
Visit patches of all these things growing in the field and see
if you can distinguish them. You will learn by this exercise
that young plants resemble each other much more than
old ones.
Exercise II: Gather mulberry leaves from a large tree,
but not on vigorous young shoots. Gather other leaves
from young trees. The leaves on young trees are lobed;
on old trees they are not.
Exercise III: Learn to tell several varieties of oak by
the leaves. Try now to determine these several varieties
when they are not more than a year or two old, and it will
be clear that the young does not resemble the old and that
the young of different species closely resemble each other.
Exercise IV: Take the most irregular flower you can
find, a larkspur for instance, or locust, or bean blossom.
Young Plants. 167
Learn the shapes of all the petals of the adult flower. Now
examine the petals in the bud. The lesson is the same,
young petals resemble each other.
Exercise V: Notice the branching of a soft maple, called
also a silver maple; its branching is deliquescent like that of
the elm. Notice the branching of the sugar-maple; it is
excurrent like that of the fir. Now find a young soft maple
and you will find that its branching is excurrent, like the
sugar-maple’s. You will learn from this lesson that the
young of one species sometimes resembles in one or more
particulars the adult of another species. These are useful
lessons in the science of embryology. It has been found
out as a principle that the growing young that resemble
each other longest are the nearest akin. Try your water-
melon, two varieties of muskmelon and cucumber seeds
again and see how old they are when you can easily dis-
tinguish the watermelon from the rest. How old are they
when you can distinguish the cucumber? How old when
you can distinguish the two varieties of muskmelon?
It is more than suspected when the young of any domin-
ant species resembles the adult of another species that the
first species is higher in the life scale; young frogs, tadpoles,
resemble fish, which are lower in the life scale; young butter-
flies, caterpillars, resemble worms, which are lower. At any
rate it will be valuable to observe carefully the plants you
study at all available ages. Do all the “baby bean’’ work
over again from these points of view.
‘Of what use are these prickly hatrs that garnish the stem?”’
The next day she showed them to him covered with a
slight hoar frost which, thanks to them, kept at a distance,
had not chilled her tender skin.
“Of what use in the fine days will be your warm coat wadded
with down?”’
The fine days came; she cast off her winter cloak and
her new branches sprang forth free from this silken envelope,
henceforward useless.
“But tf the storm rages the wind will brmse thee.”
The wind blew and the young plant, too feeble yet to
dare to fight, bent to the earth and was defended in yielding.
Sotintine in Piccola.
PART IL.
CONTENTS OF PART II.
Page
Introductory. How tojstudy a Blower... .5... 7 eee 171
Tboflorescence 5.) Sin Oo oa el Soe id oi eee rete ee 72
The Lily Bamilyo. 5.0025 ste BUS ae eee i a eee 176
The: RosecFamiily® ....5 0.002. ey ee ae ee 180
The Crowfoot Pamuly 0.5 412 2. cece <2 ee 182
The. Magnolia Famatly =: 2...) G2 2h nee aco eee 183
The Barberry Family 2.00 sc. 2 te oe os coe ee 183
The Water-lily. Pamuly ..c22 i. ons Se eal 2 184
The Poppy Family 42254: Ja. 235 oe oe ee 184
The. Mustard Family oos 0.0.0 2 -coobes +8 oR eee 185
The: Violet cb atmanlliyp att ie terete pirate Liles 186
The Pink Pamily: ..cer 0. ae he ei 187
The: Purslane, Family 202k ae ee, 187
The Mallow Family: .2).¢.. 05 42s ee ee 188
The Gerantum Family... 5. (22-50%. esta pa ee
The Pulse Pamily.. . soc. b. rable Se bo pede eee
The Teasel Family <: 29.285 sce oe oes Se eee 190
The “Ehistle Familiy. c.cettae 2 2c eek ee eer Nee 9)
The Nightshade Family. -. 225. 02. «geo wen 6 192
TheSage Panay 6 och be eae ee a eee 193
The Pokeweed Pamily 0.0.) 0.0. ..¢.- ee os oa 194
The Morning-glory Family 105) 30... e 22 195
The Nettle: Family soon. .iidals os. 2 aes 197
The Sycamore Family 7.24.66 on Ss oo ai ee 198
The Walnut Family... 04: 2.6s0 isa bie Pec ae
The Oak “Partly. 0208 senso Sow. « ba 8ae Wee ye
The Willow:Panaily. . 2.2 sche oe A 2 as 201
The Tris Baaily, 0 00 Ato oii ae Mine e ieee. ORL Ret 202
The Amaryllis Pamily 4.095 (oo.d. ee seaels ee ee 203
The Grass ‘Pamuly (e260 lie we, Boe oe ee oe Ae 203
The! Pine Familiy cc. ho a eo ates hs oe re 205
Phe ernest 1037 oe sae Sw We eee ee 206
The Messesi ns sien gate hae ee ee ee 207
A List of Twenty-eight Other Families with One or More
Common, Plants that Belong toy Diem). = 5.) 225. eee 208
How to Study a Flower. 7a
LESSON CII.
Introductory. How to Study a Flower.
Begin with a lily or a simple wild flower, as twinleaf, may-
apple or spring beauty; a lens like Figure 157, which will
cost fifty cents, or a simple dissecting microscope like
Figure 158, which may be had of the Bausch and Lomb
Optical Co., Rochester, New York, for $2.50, and a pair of
dissecting needles and a sharp knife will greatly help, and
Fig 157. Fig. 158 1-2.
for many of the smaller flowers these things will be neces-
sary. Don’t hurry to cut the flower up; pull its sepals
down without injuring them and see how many there are
of them, whether they are free from the corolla and separ-
ate from each other or not, and make notes of every fact
ol
ain
172 Nature Study.
you are able to observe about them. It will richly pay if
you will draw a sepal as accurately as you can. Next
study the petals the same way and draw one if they are
alike; if not draw one of each kind. Next study the sta-
mens the same way; be sure as to whether these are alter-
nate with the petals or sepals or both if there are twice as
many; unless you are sure there are twenty or more, count
them carefully. Do they grow on the calyx or corolla or
pistil, or receptacle? Draw one. Next study the carpels.
How many are there? Distinguish ovary, style, if any, and
stigma.. How many are there of each? Cut the ovary
across and count the cells and the seeds in the cell and learn
. if you can where the seeds are attached to theverams
Note their color, size, shape and number in a cell. Write
out the number of sepals, petals, stamens and carpels thus,
3—3—6—3 for the lily. Cut across an entire flower and
make a ground plan of it thus, Fig. 158% for the lily. What
sort of stem leaves has the plant? What sort of root-leaves,
if any? Draw one of every kind and press and preserve
for study and comparison one of each kind. What pe-
culiarity of color, odor, hardness, smoothness, etc., has any
part of the plant? Forexample: The violet has a spurred
petal; it has two petals hairy within; spring-beauty has a
long, narrow pair of thick leaves; the corolla of narcissus
has a crown, etc., etc. Compare every flower studied, with
everyone previously studied. Do not leave off the study
as soon as you have finished this inventory and found out
its name. Compare other and younger plants of the same
kind that have not yet bloomed; compare older ones or
watch a growing one till it becomes old; gather the seeds
from it at last and plant them and raise others. It is only
as the years go on that we can become really acquainted
with plants. When we have done all that we can by the
methods of study here pointed out, there is yet the great
subject of the minute anatomy of plants, and the physiology,
Inflorescence. 173
each of which has its special methods and instruments for
study that we cannot acquire away from a good laboratory.
The distribution of plants is a matter of great importance,
which can be begun in any locality. All these studies, if
pursued with real plants, are interesting and instructive
all along. Those who know most about plants, best know
also that they can never know all about them. They do
not, however, wish there was less to be known.
In the lessons which follow, some of the characteristics
of a few common and well known plants will be considered
with reference to their relationships. -Gray’s Manual
describes one hundred and twenty-nine orders of flowering
plants. These are also called families, each being named
after some characteristic plant it contains; as, for instance,
Plantaginaceae or plantain family. Plants should some-
times be studied with the name of the family to which they
belong wellin mind. A family can only be studied through
the plants which it includes. It does little or no good to
memorize the characteristics of a plant group in a book.
These must grow in one’s mind as he studies the plants of
the group in connection with those of other groups. Noth-
ing is claimed for these lessons unless they are studied in
the presence of the plants themselves. If they are thus
faithfully studied they cannot be otherwise than helpful.
As a preliminary lesson it is necessary for us to consider
some of the simpler forms of inflorescence.
LESSON CIII.
The Arrangement of Flowers on the Stem. Inflorescence.
How Flower Clusters are Related.
When flowers or fruit are arranged on the stem as we see
the wild cherry we call the cluster a raceme. Currents are
so arranged. Tongue-grass has the same kind of inflores-
i i
174 Nature Study.
cence; so have the flowers and fruit of pokeberry; so has
shepherd’s-purse. This arrangement is shown in Figure
159. It will be as good nature study work as you can do
to make a list of all the plants that have their flowers
arranged this way. The raceme has all its flowers on
a4 SS
aA es
==:
MELA
o>
=>!
a
<>
SP;
EIS
oc
SS
ae.
os
<2
Ss
Te.
S
rot
Sse
Fig. 159. Fig. 160. Fig. 162. Fig. 164.
separate pedicels of the same length which grow out at
different places along the flower stalk. When the spring-
beauties and the lilies-of-the-valley come again, see if they
have this arrangement.
Fig. 161. Fig. 163.
Another common form of inflorescence is called the spike.
It is shown in Figure 160. Look at the figures of the raceme
and spike and see if you can tell how they are related to
Inficrescence. 175
each other. The raceme becomes a spike when its flowers
become sessile.
Figure 161 is a corymb; the raceme becomes a corymb
when its lower pedicels become lengthened so as to bring
all the flowers to about the same level. Try without
reading further to look at Figures 159 and 162, and tell
how the raceme is related to the umbel. A raceme becomes
an umbel when its pedicels all grow out from the same
place. There are many plants whose flowers bloom in
umbels; the parsnip is one, Queen Anne’s lace is another,
pepper-and-salt, our pretty little harbinger-of-spring, is
another. All these and many more belong to a consider-
able order of plants called the Umbelliferae. Many of the
Umbelliferae bear compound umbels like Figure 163. A
raceme becomes a panicle, Figure 164, when its pedicels
branch so that each forms a small raceme. The flowers of
oats form a panicle. When a panicle thickens by becom-
ime much branched we call it a thyrse. The lilac and
horse-chestnut are good examples. 7
Many flowers grow in heads, Figure
165. All the large order called com-
positae which contains the asters, gol-
den-rods, dandelions, Spanish needles
and many others grow so. The teasel
sycamore and clover are other examples.
See 1f you can tell from Figures 162 and
165 how the umbel might become a
head. If its pedicels shortened till all
its flowers became sessile 1t would form
a head. What is the relationship between the raceme and
head?
All these forms of inflorescence may be naked, that 1s,
they may have no bracts in among the flowers. This is
true of the shepherd’s-purse and many other cruciferous
flowers. If a spike has bracts in among its crowded flowers
176 Nature Study.
and if it hangs down,—is pendulous,—we call it an ament
or catkin. The staminate flowers of many of our forest
trees are in aments.
It is not the purpose of this lesson to multiply defini-
tions, but to show kinship of flower clusters and the lesson
is not learned until the student can look at the pictures
and tell at once how all are related to the raceme and to
each other; he must also be able to go to his flowers and
pick out the several kinds. He will not have been long at
this exercise before he will learn that the several forms
shade into each other. Gradually the lower pedicels of
the raceme lengthen until at last a corymb is the result;
but no one can tell where one leaves off and the other
_ begins. He will find in the lilac, the asters, the goldenrods
and many other flowers, these forms mixed in every way.
Nature does not always present the sharp lines our figures
show so clearly. Everywhere her steps are so gradual
that all careful students now have to think that her sharper
distinctions have gradually grown up and presented us at
last with all her varied forms. Try to interpret this:
A raceme — pedicels becomes a spike.
A raceme — rachis becomes an umbel.
A raceme +- longer lower petioles becomes a corymb.
A raceme + branched pedicels become a panicle.
A raceme — rachis and pedicels become a head. |
Flowers are, as every one knows, often solitary, that is
just one growing at the end of a stem; this arrests the growth
of the stem and is one form of determinate inflorescence.
When a stem begins to bloom at the botton and continues
to grow at the top, as the shepherd’s-purse or plantain, it
may bloom on as long.as the season lasts; it 1s indeter-
minate. é
If, however, a’ stem begins to bloom at the top yamd
blooms downward, or if a flower cluster begins to bloom at
The Kinship of Plants. 17
“I
the center and blooms outward, it cannot bloom indefinitely ;
its blooming in such cases is called determinate.
LESSON CIV.
The Lily Family.
The Lilzaceae.
The Liliaceae. The Kinship of Plants: What it Means to
Trace Kinship.
Every one knows the lily; it is famous in all countries
and all literatures. The trillium, smilax, onion, star-of-
Bethlehem, grape-hyacinth, lily-of-the-valley, Solomon’s-
seal, asparagus, dog-tooth violet, and other less common
plants belong to the lily family. Instead of saying calyx
and corolla, we give one name, perianih, to both in the
lily, because both are generally colored alike. The peri-
anth consists of six floral leaves. There are generally six
stamens and a three-celled ovary. Many of the liliaceae
grow from some sort of underground fleshy part like the
rootstock of Solomon’s-seal, see Fig. 55, the bulb of the lily,
Figure 71, etc. This enables them to bloom early, com-
pare Lesson LXXXII. It is also true that some of the
lilies have the blossom already formed underground, so
that when the warm days of spring come there is nothing
to do but push them above ground and unfold them.
As the season advances, mark the spot where trilliums
and dog-tooth violets grow and dig them up in September
and every month thereafter to see the slowly forming
flower.
Series I. Seed-Bearing Plants.
Two series of plants are recognized; those that bear seed
and those that do not. The lily bears seeds and so belongs
178 Nature Study.
to the first series, the Spermatophytes or seed-bearing
plants.
Classes.
There are two classes of seed-bearing plants; those with —
one seed leaf called monocotyledons, and those with two
called dicotyledons. The lilies belong to the monocotyle-
dons, that is, they have but one seed-leaf. Every one
should examine germinating corn and beans at several
different stages to see the difference between plants with
one and two seed-leaves. The bean is a dicotyledon. The
lilies have stems like the smilax, palm and corn, see Lesson
LXXVI. The leaves are generally parallel veined; com-
pare the venation of the lily or dog-tooth violet with the
maple, (palmately veined) and the beech (pinnately
veined).. It is important to notice also that the parts of
the flower are generally in threes, as in the case of the lily,
three sepals, three petals, six (two times three) stamens
and a three-celled ovary.
Famulies.
These monocotyledonous qualities, the lily family shares
with other monocotyledonous families, as the iris family,
the amarylis family, the grass family and several others.
Three lessons following this, Lessons CX XIX, CX XX and
CXX XI will be about the blue flag, the amaryllis and the
oats; and every one should note especially how they differ
from the lily; this will be a beginning of acquaintanceship
with family differences. The various families are made up of
more or fewer groups each of which is called a genus (plural
genera). The members of each genus are more nearly
related than they are to the members of other genera;
among the liliaceae the Solomon’s-seal, the dog-tooth violet,
the lily and the trillium represent four genera. These
should be carefully compared with each other to get a
The Kinship of Plants. 179
notion of differences that are generic. Notice in Solomon’s-
seal that the bracts are not green but membranaceous,
scarious we call them; that the stamens grow on the peri-
anth, perigynous, that the perianth is united, cylindrical and
six-notched at the summit, that the anthers open within,
(introrse), and that none of these things are trueof the others;
they have no bracts, their stamens are hypogynous, 7. e.,
they grow on the receptacle or at the base of the distinct
segments of the perianth; that they open on the back or
at the side or, in the case of the trillium, sometimes within.
Genera.
The Erythronium (dog-tooth violet) is distinguished in
this group by a scape which comes from a solid bulb and
bears generally a single flower and a pair of smooth shining
leaves that sheathe the scape at the base.
The lily is borne on a leafy stem from a scaly bulb. Its
perianth-parts are colored alike and wither.
The trillium bears three leaves in a whorl, its sepals are
leaf-like and persistent; it has a solitary flower and its
leaf-bearing stem comes from a tuber-like rootstock.
Compare the pistils of these four and any other liliaceous
genera; compare their seeds. When we have come to look
unweariedly and exhaustively at things, comparing one
with another, we shall have one necessary accomplishment
of the naturalist.
Species.
There are two common dog-tooth violets, the yellow and
the white. These are different species. Find them and
mame out all their difteremces. - Which has leaves with
few or no spots? Which has spreading stigmas? Which
has teeth on the inner division of its perianth? These
differences of color and slight differences of form when they
reappear with considerable certainty in the descendents of
180 Nature Study.
each, constitute specie-distinctions. You will often have
trouble in distinguishing species. Naturalists, however
learned they may be, have this trouble. This is because
species vary. If you seek seriously to know all the plants
of your neighborhood by name you will quickly learn that
species change. No one can define species with a definition
that will always hold. Man is a species; one does not have
to look long at a negro, an Indian, a Chinaman, and a
white man to learn that species greatly vary. We call the
different sorts varieties when they breed true, have a
habitat of their own and between their home and the home
of the species all the differences fade gradually out. There
are many varieties of Indian corn known to all of us.
If now we label the yellow dog-tooth violet, it is, first:
Erythronium americanum, this is its specific name. All
the millions of individuals, its uncles, cousins and grand-
fathers, resemble it enough to be mistaken for i) )Wiaey
are its near kin. Its generic name is Erythronium. Its
relatives of this degree are more numerous but less akin,
have fewer points in common with it. Its order name is.
Liliaceae and of relatives removed so far there is an almost
uncountable number of individuals but they have yet
fewer points in common.
It belongs to the monocotyledons and at this remove, its
relations again vastly increase, but they are less akin, the
grasses are now among them.
The monocotyledons and the dicotyledons belong to the
Spermatophytes. At this remove, all plants that bear seeds
are akin to the dog-tooth violet. Finally it is a plant
instead of an animal and this remove makes the number
of its relations unthinkably great. It is alive instead of
dead and this makes the animals more like it than minerals
are. To classify is to trace out kinship. |
Dog-tooth violet is a living thing, a plant, a spermato-
phyte, a monocotyledon, a liliaceous plant, an erithronium,
The Rose Family. 181
an Erithronium americanum. If we know the meaning
of these words they will all give us information about our
plant.
“It is the naturalist rather than nature that draws hard
and fast lines everywhere and marks out abrupt boundaries
where she shades off with gradations.
One of the lessons which the philosophical naturalist
learns or has to learn is that differences, the most wide and
real, in the main, and the most essential, may nevertheless,
be here and there bridged over by gradations.”’
Asa Gray in Darwiniana, page 289.
LESSON €V.-
The Rose Family.
The Rosaceae.
The apple, peach, pear, plum, cherry, wild cherry,
spiraea, Waldsteinia, strawberry, mountain ash, haw-
thorn,. raspberry and many other common plants as well
as the rose belong to this family. Find out the character-
istics of this order by examining the flowers instead of
reading from a book. Get a wild rose for your first lesson.
How many petals hasit? Are they all separate? Do they
fall off or pull off in one piece or more than one? Do all
the sepals grow together at the base? Are the stamens
Note—The order of these lessons has been determined by the
sequence of Plant Families in Gray’s Manual, except in the case of
the Lily Family and the Rose Family. These I have placed first
because they are well known, comparatively simple and can be
had at almost any time of year either cultivated or wild.
In teaching, the order of these lessons is of so little importance
that it should be determined solely by the ease of obtaining abund-
ance of fresh material for study.
182 Nature Study.
few or many? Do the stamens and petals grow on the
receptacle with the sepals and pistils or do they grow on
the rim of the calyx tube? Are the pistils few or many?
If you will answer these questions you will know some
marked characteristics of the rose, the genus Rosa which
gives its name to the family. If you memorize the follow-
ing you will know words only.
The rosacae are plants with regular flowers; they have
five petals and many stamens, all of which grow on the calyx
tube: that 1s, they are perigynous. The pistils are one to
many and except in apples, hawthorns and mountain
ashes they are distinct. It is important im (he seuuem
of this family that the student become acquainted with the
receptacle,—the end of the stem on which the flower is
borne. In spiraea, this is cup shaped, in the strawberry it
is conical, fleshy and the seeds are imbedded in i imegme
rose it is urn shaped; open the urn and find the carpels.
In the apple the parts are differently arranged according
to the age of the blossom or growing young fruit. The
perigynous parts become epigynous (on the gynoecium or
pistil instead of around it) by the growing together of the
thickened calyx and carpels. In the raspberry the re-
ceptacle is conical but not fleshy; the fruit comes off and
leaves it on the stem. In the blackberry it is fleshy and
comes off with the fruit; is a part of it.
PESSON Cyvae
The Crowfoot Family.
The Ranunculaceae.
The clematis, wind-flower, liverleaf, the meadow-rue,
the rue-anemone, eighteen species of crowfoot, the marsh-
marigold, the columbine, yellowrocot, larkspur, and other
less common plants belong to this family.
The Magnoliao Family. 183
Any of these flowers will do for a study of the family.
Several of them should be collected: This will be easy in
the spring. The sepals, petals (aj any), numerous stamens,
and one to many pistils are all distinct and unconnected;
This is why your systematic botany describes this family
first. Nearly all of the family are herbs; the juice 1s color-
less and generally acrid. The marsh-marigold is very
common; it grows in wet meadows and marshes; often it
covers several acres. Its gold on its background of green
is very striking in April and May; its sepals are yellow; it
has no petals. It is often cultivated as a potted plant.
Its stamens are numerous and its pistils are about ten; it
has large, roundish or sometimes kidney-shaped leaves.
The wind-flower, Anemone nemorosa blooms at about
the same time. Hunt for it along the edge of the woods.
It differs from the marsh-marigold in size, color, foliage and
habitat. The sepals are’ white, generally tinged with
purple or sometimes blue, the flower is on a long stalk
remote from the involucre of compound leaves.
The liverleaf grows from a rosette of leaves on hairy
stalks that lived over the winter. It has an involucre of
simple leaves close to the flower. The flowers of this
family are easy to study because all the whorls are separate
and neither sepals, petals, stamens nor pistils are united
among themselves. Many of them come early in the spring
and most of them invite to study by their beauty.
There can be no pleasanter introduction to plants than
through these flowers. Remember that when only one
whorl of floral leaves is present we call it a calyx and its
parts sepals and you cannot go astray.
184 Nature Study
LESSON CVII.
The Magnolia Family.
The Magnoltaceae.
The Magncliaceae are much like the Ranunculaceae in
their flowers: The pistils, however, cohere and cover the
receptacle. They are trees instead of herbs. We need to
learn about this family because our beautiful and valuable
tulip belongs here. We call it poplar, especially when we
speak of poplar lumber we mean the lumber of the tulip.
it is soft, light, durable, easy to work. Our fathers used
to dig sugar troughs and watering troughs out of it. They
split it into rails, hued it into timbers for their houses and
barns and covered their buildings with shingles cut from it.
Its large, bell-shaped, orange-marked corolla and its green
leaves, truncated at the end, mark it very distinctly among
trees. Jt has three reflexed sepals and six jpetaieummme
stamens open cutward: Figure 83 shows one of its winged
seeds hulled out from its united carpels.
LESSON CVIII.
The Barberry Family.
The Berberidaceae.
We may acquaint ourselves with the Berberidaceae
through the barberry bush (see Figure 68 for the leaves),
or the twinleaf, one of our commonest spring flowers.
The stamens are fewer than in Ranunculaceae, they equal
the petals in number and are opposite to them. The sepals
fall off as soon as the flower opens; so one often makes the
mistake of calling the white petals the calyx. The anthers
open by lids at the top; the pod also opens by a lid hinged
The Mustard Famuly. 185
at one side. The flower stalk is low and the flower an inch
broad. The leaf is divided into half-egg-shaped leaflets.
The may-apple is an eratic member of this family,-with
stamens twice as many as the petals and not opening by
lids at the top. It has a peltate leaf anda large fleshy
berry.
LESSON CIX.
The Water-lily Family.
The Nymphaeaceae.
This family is close akin to the foregoing. Every one
may have an opportunity to study it in the white water-
lily which can be had in the markets where it does not
grow. Consult Lessons XLV and LXXI.
Find the pistil and see that it is made up of many united
carpels, that the stamens grow on it, and that the petals
eee im part adherent to it.
LESSON CX.
The Poppy Family.
The Papaveraceae.
We ought to know something of the Papaveraceae on
account of the bloodroot. This fiower is one of our early
spring friends. It is solitary, white, has two sepals which
fall when the fiower opens, eight to twelve petals and
some twenty-four stamens. The pistil is one-celled but is
made up of two carpels as we learn from the two rows of
seeds on its wall. It grows from a short rootstock full of
a red acrid juice. Its leaf is rounded and palmately lobed.
186 Nature Study.
LESSON CXI.
The Mustard Family.
The Cructferae.
This family is a large one; to it belong the mustards, the
cresses, the radish, cabbage, turnips, peppergrass, shep-
herd’s-purse, sweet-alyssum, and many other plants.
It is what we call a very natural family, that is it is
easily distinguished from other families by peculiarities
that mark its relationships; when we distinguish plants by
size, color, leaf-shape, etc., as we often can, we are guided
by artificial marks as these give little hint of real relation-
ships. An artificial key seizes on distinctions easily made
out; a natural key, if one were possible, would guide us to
the plant by its most significant marks of relationship;
a scientific botany bases its distinctions on natural differ-
ences as much as possible; but because these are often not
known, and often very difficult of observation, every key
must be more or less artificial.
The Cruciferae have four petals arranged 1n the form of a
cross: they have six stamens, four long and two short, tetra-
dynamous, and the pod is a silique, long pod like mustard,
or silicle, a short pod like that of shepherd’s-purse. These
pods are two-celled, separated by a thin partition. The
flowers are so nearly alike that generic characters are taken
from pods and seeds. An early spring flower, Dentaria
laciniata, called in Gray toothwort and pepper-root, is a
good plant on account of the larger flower it bears with
which to begin an acquaintance with this family; the
toothwort grows from a rootstock deep in the ground; it
has a whorl of three much-divided leaves; the flowers are
white or rose color.
The Purslane Family. 187
LESSON CXII.
The Violet Family.
Violaceae.
The violet needs no introduction anywhere. It comes
early and stays late. Any one who will try, may acquaint
himself with the parts of a flower through it as there can
be no doubt about its identity.
The common blue violet, Viola cucullata, is taken for
description. The sepals are five slightly united, auriculate,
green and persistent. The petals are five, one of them
spurred; the stamens also are five, the anthers grow
slightly together over the pistil which is made up of three
carpels. See the open pods at the nght in Figure 53.
The leaves and flower-stalks grow up directly from the
underground rootstock. The species varies greatly; in
color from deep violet blue to white; in surface from
glabrous to villous-pubescent; in leaf-shape from roundish
heart-shape to kidney-shape or crenate. See description
of Figure 53 for its flowers that never open.
LESSON CXIII.
The Pink Family.
The Caryophyllaceae.
Pinks and carnations we all know and the chickweeds we
all should know, they grow everywhere in damp grounds ;—
low plants, about six inches high, with little star-shaped
flowers. The sepals are four to five; the petals are four to
five but so deeply two-cleft that they seem to be eight or
ten. The plant can be told by its deep cleft white petals.
188 Nature Study.
The stamens are eight to ten or fewer; the styles are three
rarely four or five, opposite the sepals; the seed-pod, how-
ever, is but one-celled; it contains many seeds. The
leaves are opposite and on the common chickweed they
have hairy petioles, on the great chickweed they are sessile.
LESSON CXIV.
The Purslane Family.
The Portulacaceae.
Two of our commonest plants belong to this family,
purslane and the spring-beauty. We can well learn from
them what an unsymmetrical flower is. Symmetry refers
to number. The spring-beauty has two green sepals and
generally five petals with a stamen on each petal claw.
The style is three-cleft so we conclude the carpels are three.
The formula, then is, for the flower, 2, 5, 5, 3 thejatmalgers
referring in order to sepals, petals, stamens and pistils.
The flower is therefore unsymmetrical. Stonecrop is
symmetrical; if you know it you should compare it with
spring-beauty; it has sepals 4 or 5, petals 4 or 5, stamens
8 or 10, (twice 4 or 5) and pistils 4 or 5. Compare also a
flax blossom the formula of which is 5, 5, 5, 5.
Purslane is a smooth, prostrate, thick-leaved, succulent
plant, the bane of gardeners. It flourishes in the hottest
part of July and August. See if its formula is 2) > onvomee
to 20, 3 to 8. Compare Lesson LX XII, especially Figure
it?
The Pulse Family. 189
LESSON CXV.
The Mallow Family.
Malvaceae.
Several very common plants belong to this family, the
holyhock, common mallow, the Hibiscus, the velvet leaf,
the bladder-ketmia and the Althaea. From some of these
flowers we should learn what monadelphous stamens are.
The word means of one brotherhood. A tube rises up from
the short claws of the petals which bears the stamens.
We should also learn what valvate in the bud and con-
volute in the bud mean. Valvate describes the sepals the
edges of which just meet. Convolute describes the corolla
the edges of which overlap in such fashion that each petal
has one edge in and one out. We can also learn well from
the Althaea, the holyhock and mallow what an involucel
is. Look for a sort of secondary or exterior calyx 6 to 9-
cleft around the holyhock and Altheae, of three pieces
around the mallow.
LESSON CXVI.
The Geranium Family.
Gerantaceae.
This family contains Oxalis or wood-sorrel, the touch-
me-not, the Pelargonium, the Geranium or cranesbill and
the nasturtion, called also the Nasturtium, but this, one
must not forget is also the generic name of the water-
cress.
The Oxalis may be studied as it grows wild almost
everywhere and it can also be had at the greenhouse; it is
190 Nature Study.
symmetrical with the formula 5,5, 10, 5. The ¢atpers
are united into a five-celled ovary. Find out how these
open; it is unusual.
The nasturtion offers us a good opportunity to learn
what an irregular flower is. When the parts of the same
whorl are unlike we call the flower irregular” Tinig@ic
noticeably true of the petals of a pansy or violet; one is
spurred. See if the sepals of the nasturtion are not unlike;
see if the petals are not, and the stamens. Examine also
the touch-me-not and see that it a a spurred sepal
larger tam the fest.
LESSON CXVII.
The Pulse Family.
The Leguminosae.
To this family belong the locust and the honey-locust,
trees, the bean and pea, climbing vines, the @redauar
a shrub, the Wistaria, a woody twiner, the white and red
clover, sweet clover and alfalfa, etc., herbs. It will thus
be seen that size and form have little to do with the make
up of families. The flowers of this order have usually
papilionaceous corollas and we should acquaint ourselves
with this in the pea, bean, locust, redbud, etc.; they have
five petals, the lower called the keel, carina, two side ones
called the wings, alae, and a large enveloping one called
the banner, vexillum, see Figure. We have seen mona-
delphous stamens in the Malvaceae; we may now see
diadelphous stamens in the clover and alfalfa, or better
still in the locust and pea as the flowers are larger; the
word diadelphous means in two groups. Generally there
are nine joined by their filaments in one group and one_
alone or almost separate from the rest.
The Thistleo Famuly. 191
We should also learn well what a legume is as this is the
peculiarity that gives its name to the family. A legume
is a one-celled pod, splitting into halves but bearing the
seeds all on the ventral suture only, in one row. The pea
and the bean pods are very familiar examples. Consult
Lesson LXXXVI for a great service rendered the soil by
the Leguminosae. In North Carolina peas are sown along
with other crops and they restore the soil for them as clover
does for us in the North.
LESSON CXVIII.
The Teasel Family.
The Dtipsaceae.
The wild teasel may be seen everywhere along roadsides,
in pastures and in untilled corners. Its flowers are in a
dense, large head, conical-elliptical, surrounded by an
involucre that is loose and longer than the head, but the
stamens are not syngenesious. The plants are stout,
coarse, prickly biennials. The fuller’s teasel, supposed to
be derived from this, has the points of its chaffy head,
hooked, and is used for raising a nap on woolen cloth.
The chaff of the wild teasel has long, tapering, straight
points.
The calyx is coherent but has no pappus. The corolla is
four-cleft, nearly regular, a fine purple in color. The
numerous corollas give the head an appearance as pleasing
as its many daggers will allow. The four stamens grow
separate on the corolla-tube.
192 Nature Study.
LESSON CXIX.
The Thistle Family.
The Compositae.
The sunflowers, the asters, the goldenrods, the daisies,
the burdock, the Spanish needles, the cockle-burs, the
dog-fennel, the tansy, the ironweed, the yarrow, the ever-
lastings, the chrysanthemum, the lettuce, the ragweeds and
many other less known plants belong to this family. The
dandelion may be found eight months or more of the year;
hunt in it or the sunflower for these characteristics of the
family: Flowers in a close head, surrounded by an in-
volucre of many bracts, which are generally green and with
stamens united by their anthers, (syngenesious). If the
blossom of the dandelion is compared with Figure 72
a good beginning can be made with this family. It may
be easily noticed that all the flowers of the dandelion are
alike. Compare now the sunflower; two kinds will be
found, the showy outside flowers with a strap-shaped
corolla and the less showy flowers of the head with tubular
corollas. Do asters, daisies and thistles resemble the
dandelion or the sunflower most, in this respect? Much
profit and pleasure could come from a comparison of all the
compositae with the dandelion. Examine the involucre
of the dandelion; is it green? compare it with the involucre
of the common everlasting; is it green? compare the in-
volucre of the bur-marigold, (common beggar-tick) gener-
ally called Spanish needle. Notice that the Spanish needle’s
involucre is very leaf-like, is expanded into a small blade,
is veined like a small leaf, and helps us to see that the bracts
of the involucre are reduced leaves. Compare Lesson
XLII.
Compare carefully the pappus on twenty different kinds
The Mint Family. | 193
of flowers belonging to the compositae; the Spanish needle,
sunflower and dandelion would be very instructive in this
respect. The dandelion has a hair-like pappus, Figure. 89.
The Spanish needle’s is reduced in number to two or in
some species to three or four, barbed stickers shown in
Figure 101. The pappus of the sunflower consists of small
scales which easily fall off. The chrysanthemum, ox-eye
daisy, 1s entirely without pappus, 1. e., apetalons.
Notice that the plaintain-leaved everlasting is dioecious,
the cocklebur and ragweed are monoecious while the
dandelion has perfect flowers. We will learn by this
study how very different in many important respects are
the flowers that are classed together in this family.
It is interesting that the prickly lettuce and many other
compositae have all their flowers ligulate, the everlasting
and some others have all theirs tubular, while the asters
and a large number in addition have both ligulate and
tubular flowers.
LESSON CXX.
The Nightshade Family.
The Solanaceae.
To this family belong, beside nightshade, the potato,
the tomato, the tobacco, the ground cherry and the James-
town weed (‘‘jimson weed’’) Datura stramonium. Study
these common plants for the order characteristics; having
studied all but one see if you can tell by a further study of
that one why it should belong to the same order. There
will be real progress in the effort to do this.
Datura has a green, prismatic, five-toothed calyx, a
corolla three inches long, white and five-toothed; there are
five stamens on the corolla tube and alternate with its
194 Nature Study.
lobes. The fruit is a many-seeded capsule armed with
prickles. Is it two or four-celled at the bottom of the
capsule? At the top? The jimson is a tall, strong, ill-
scented annual; smooth, with a green stem, leaves alter-
nate, sinuate and toothed. The flowers grow in forks
of the stem on short -peduncles.. Compareie@e
nightshade and potato blossoms with this and each other,
natt by natt, calyx, corolla, androecium, and gynoecium.
The importance of doing this can hardly be overstated.
No teacher and no book can do this for you.
LESSON CXXI.
The Mint Family.
Labiatae.
Study this family through the everywhere common cat-
mint or the garden sage or the little gill-over-the-ground.
Herbs with square stems opposite aromatic leaves, a more
or less two-lipped corolla, four stamens, two long and
two short (didynamous) or only two (diandrous) and a
deeply four-lobed ovary with style rising between the
smooth or only slightly rough seeds.
The much-used pennyroyal belongs to this family.
BESSON -CXOCH:
The Pokeweed.
The Phytolaccaceae.
The only plant described under this family in Gray’s
Manual is pokeweed. Whatever qualities this plant has
are, therefore, the qualities of the family: We ¢am@ledrm
accurately from the fruit or flower what a racemeis. The
The Morning-Glory Famuly. 195
flower has five sepals, no petals, ten stamens, and five car-
pelss united into a pistil of as many cells. The styles are
tem, Ihe dark purple berries are eagerly eaten by: the
robins and thrushes and should be left, on unused ground,
imnoind food. The sicculent stem six to nine feet high
grows from a large, poisonous root used in medicine.
Emerson’s definition of a weed is ‘“‘A plant whose virtues
ewe mot yet been discovered.” Pokeweed has at least
two known virtues and is therefore not a weed.
LESSON CXXIII.
The Morning-Glory Family.
The Convolvulaceae.
A very common plant cultivated for ornamental purposes,
the morning-glory, a very useful herb, the sweet potato
and a very interesting group of twining parasites, the
dodders, belong to this family.
The morning-glory has a calyx of five long, narrow,
imbricated (overlapping) sepals, and a corolla of five united
petals. The corolla is purple, blue or white and funnel-
mommed: | When the parts of the corolla are united, we
determine of how many parts it is composed by the number
of its lobes or the number of seams by which it appears to
hewe Stown together. Try to determine the number of
parts of several gamopetalous flowers in this way, as, for
instance, the holyhock, the hibiscus, the pumpkin, the .
watermelon, cucumber, potato, ground-cherry, sage, catnip
and sunflower and any other gamopetalous flower with
which you meet. Much practice alone will help you in all
cases to determine. The gynoecium, (a name for all the
carpels put together) of the morning-glory is composed of
three carpels. How can you determine this? Cut across
196 Nature Study.
the ovary and count the cells, this is one way. How many
stigmas are there? This is another way. Is the ovary
lobed to any degree? How many styles are there? Any
one of these ways may mislead the beginner sometimes;
the thing to do is to look at many flowers with care and
compare your observations with what others have seen.
The sweet potato rarely blooms when it is raised for
commercial purposes as it is with us. It furnishes a good
example of a trailing vine that roots at the joints. See
how many kinds of support you can find stems adopting;
as, for instance, upright stems, the oak; right-handed
twining stems, the morning-glory; left-handed, twining
stems, the hops; (as one looks down on a twining hop
it moves with the hands of a watch held face upward;
as one looks down on a morning-glory it twines against
the hands of a watch. The hop goes with the sun; the
morning-glory against 1t. Does the bean twine like hop
or morning-glory? ‘The hop is called a sinistrorse climber,
the morning-glory a dextrorse;) climbing by tendrils that
are branches, grapevines; climbing by tendrils that are
leaflets, the pea; climbing by tendrils that are stipules,
greenbrier; stems that bend over to the ground for rest,
the raspberry, etc. The sweet potato is propagated with
us by means of slips raised in hotbeds. One bushel will
produce from 3,000 to 5,000 slips (Bailey).
The dodder Cuscuta arvensis, frequents wet places. I
have seen it along the flood plains of the Wabash at Peru
and Terre Haute and I have no doubt it occurs all along
the stream. It is a small, white, or yellowish-white-stem-
med, leafless plant that twines about smartweed and other
river-bottom plants, grows suckers on the side next to the
host and lives at its expense. It has small whitish scales
instead of leaves and all its floral organs are pale. The
calyx has five obtuse lobes; the corolla lobes are acuminate,
longer than the tube, inflexed. It has five stamens alter-
The Nettle Family. 197
nate with the corolla lobes; the ovary is two-celled, four-
ovuled. This description is written from Cuscuta arvensis;
it will vary somewhat with the species of the dodder.
Notice how small is the stem and how large in proportion
are the flowers and seed pods. The dodder has met the
usual fate of the parasite; it gets digested food from its
host and does not need foliage leaves; it has none; it has
doubtless lost them from disuse; its pale scales are rudi-
mentary organs. It has no roots extending to the ground
for the same reason; and no stem to supportit. It matures
many seeds as this is its means of survival. It can cling,
pierce its host and get food and reproduce. It is wholly a
dependent, a degenerate. It is eminently adapted to its
kind of life. Itis not necessarily on the road to extermina-
tion but it is barred from the independent, aspiring life of
the oak or thistle. It has been sentenced for laziness and
theft to a sort of perdition, not to extinction. Don’t seek
for a permanent thousand-dollar clerkship for yourself or
for your boy at Washington.
LESSON CXXIV.
The Nettle Family.
The Urticaceae.
The elms belong to this family. The slippery elm, called
also the red elm, may be known among elms by its large,
(four to eight inches) and very rough leaves, its slippery
inner bark and its nearly sessile flowers. The bark is used
in medicine. The leaves are oblique, Figure 26, alternate
and two-ranked as are the leaves of all the elms. The
American or white elm is somewhat commoner, especially
in lawns, see Lesson IV, Figure 5. Its leaves are two to
198 Nature Study.
four inches. Its buds and branchlets are smooth and its
branches never corky. Its fruit is winged all round
notched at the apex and ciliate. Its flowers are on slender
drooping pedicels. :
There are two other, rarer elms, the cork or rock elm
and the wahoo or winged, both of which have corky
branches. The first of these has its leaf-veins nearly twice
as close together as any other elm; about thirty in the
cork-elm to seventeen in the American elm and the leaf is
very smooth.
The English or field elm is sometimes met with as a shade
tree; it has very small leaves, about half the size of the
American elm.
The elm blossoms are polygamous; that is some are
sterile and some are fertile and some are perfect. They
have a four to nine-cleft calyx, four to nine stamens and
a one to two-celled ovary; the seed is single,
The hackberry also belongs to this order; it bears a
globular drupe (fruit with stone within) on a peduncle
twice as long as the petioles of its leaves and can be told
among our trees by this and its oblique leaves. Its
polygamous-monoecious flowers have a five to six-parted
calyx with five to six stamens and a one-celled ovary.
The osage orange, so extensively used for hedges, the
mulberry, the nettle, monoecious or dioecious, tmemiem
and the hemp, dioecious, all belong to this family and may
be studied in comparison with other members of it.
LESSON CXXV.
The Plane-Tree Family.
The Platanaceae.
Our sycamore is our largest tree; it 1s common along all
our streams; it is striking on account of its smooth, white
bark and its large palmately veined, palmately lobed leaves.
The Walnut Famuly. 199
The petioles of the leaves cover and protect the buds as
long as the leaves hang on. Its flowers are monoecious,
in separate, naked heads. Scales are mingled among the
flowers. The seeds are furnished with a ring of hairs
about the base.
LESSON CXXVI.
The Walnut Family.
The Juglandaceae.
This family is made up of the hickories and walnuts.
Of the walnuts there are two kinds common with us, the
black walnut, with the unhulled nut round, and the white
walnut, called also the butternut, with the unhulled nut
elliptical, hairy, and glutinous; both kinds have alternate,
pinnately compound leaves. The wood and the bark of the
butternut are lighter colored than those of the black walnut,
and, in general, have fewer leaflets on a leaf (five to seven
pairs) than the black walnut (7 to nine pairs). All the
trees of this family are monoecious, the sterile flowers
beine in catkins, (aments) and the fertile single or in
small clusters. The fertile flowers of the walnut have a
four-toothed calyx which bears four small petals; styles
and stigmas, two. The sterile have a calyx three to six
cleft and clinging to a bract, twelve to forty stamens.
There are two common shellbark hickories, one Carya
alba, which bears a thin-shelled nut about an inch long
and has from five to seven leaflets. The other, Carya
sulcata has a nut one and a half to two inches long with a
thick shell hard to crack; it has seven to nine leaflets.
The sterile catkins are generally in threes. The fertile
flowers have a four-toothed calyx and two to four sessile
200 Nature Study.
stigmas. There are also two bitternuts; one, called pig-
nut, has from five to seven leaflets with the catkins and
young leaves smooth. The nut is oblong or oval, one and ~
a half to two inches long. -The other is swamp-hickory
with nut globular and about an inch long, and having
seven to eleven leaflets. The catkins and young leaves
are more or less pubescent. The bark of the bittemgman
does not peel off in strips running up and down the tree as
it does in the shagbark. The walnuts and shagbarks are
among our most valuable timber.
LESSON CXXVII.
The Oak Family.
The Cupuliferae.
The oaks, birches, beeches, the chestnut, the hazelnut,
the water-beech, the ironwood, and the alders belong to
the Cupuliferae. The word means cupule-bearing or cup-
bearing; it refers to the cup in which the acoris) on maim
grow. This is made up of many small scales in the oak;
the many scales form a sort of four-lobed involucre in the
chestnut, and beech. The scale is leaf-like in the water-
beech, and a closed sack in the ironwood. The flowers are
monoecious, the sterile in catkins, the fertile, solitary or
variously clustered. It is quite impossible to get a knowl-
edge of these small, inconspicuous green or greenish-yellow
flowers without carefully examining them in the spring.
The leaves of all this family are pinni-veined, see Figures
13, 14, 16, 17, 20 and 26. The birch may be known by its
bark peeling off in horizontal strips, the ironwood by its
bark shredded longitudinally, the oaks by the fact that
they bear acorns; the hazelnut is a bush not a tree, and
The Willow Famuly. 201
its nut is inclosed in leaf-like bracts. We should learn
from this lesson what a cupule is—the cup of an acorn,
what a pinni-veined leaf is. What a lobed leaf is (white
and red oaks have them). What a serrate leaf is (the
chestnut and beech have them). What a chestnut-bur
is Fig. 104. What monoecious trees are. Lessons
XVIII and XIX.
Red oaks, of which we have four, have their lobes awned;:
Figure 16. White oaks, of which we also have four, have
their lobes rounded, Figure 14. Chestnut-oak leaves have
their leaves notched not lobed. Figures 13 and 17.
LESSON CXXVITI.
The Willow Family.
The Salicaceae.
The willows and poplars belong to this family. The
white willow can be told by its yellowish twigs, and the
whitish under side of its somewhat short leaves. It is one
of the largest willows we have, is often planted on lawns.
The black willow has foliage of a much darker green,
and is the common willow along streams.
The long-leaved willow has the notches, serrations, far
apart on its long, narrow, whitish leaves.
The weeping willow no one can mistake on account of
its drooping branches.
The ‘‘pussy willow’ (Salix discolor) can be told by its
thick aments, oblong-cylindrical, close-sessile, one inch or
more long, appearing before the leaves in earliest April.
These aments are the flowers of the willow. The family
is dioecious, so seeds grow on only a part of the poplars and
willows.
202 Nature Study.
In the “‘pussy willow” catkins, one flower will be found
to each bract without a perianth. These bracts are dark
red or brown becoming black and are clothed, in long,
glossy hairs.
There are at least fifteen other kinds of willows and some —
of these kinds have been cultivated by gardeners and
intercrossed until many widely different varieties have
been produced. That such a thing can be done is very
interesting; 1t throws much light on our very many kinds
of animals and plants. Read Darwin’s “‘Animals and
Plants Under Domestication.”’
The Carolina poplar, cottonwood, is much used as a
shade tree on account of its beauty and rapid growth; it
has large, crenate, deltoid, flat-petioled leaves. The
Lombardy poplar has similar leaves but they are smaller,
wider than long and the branches grow up almost straight
close to the tree giving it a spire-shaped appearance by
which it can be told.
The white poplar has leaves slightly lobed rather than
notched, very white-tomentose below; the young twigs
are white hairy as well.
LESSON CXXIX.
The Iris Family.
The Iridaceae.
This family, the Iridaceae, is introduced solely on ac-
count of the blue flag which grows in damp places along
streams. Notice that its perianth is six-cleft, that it is
adherent to the ovary, (is it in the lily?) and that it has
but three stamens, the anthers of which open outward,
extrorse, one under or outside of each of the three large
The Grass Family. 203
expanded petalloid stigmas. Compare Lesson XLVI on
the leaf-origin of the pistil. Notice the two-ranked, sword-
shaped, equitant leaves.
Compare the flower of Ins with Crocus. Learn from
these what an epigynous flower is, 1. e., a flower in which
the floral organs grow on the pistil. Is the perianth-tube
of the crocus longer than it isin the iris? Does the crocus
flower grow sessile on the corm? Are all the leaves of the
crocus root-leaves?
LESSON CXXX.
The Amaryllis Family.
The Amaryllidaceae.
This family is important for us because the narcissus,
snowdrop, amaryllis and daffodil, common garden flowers,
belong toit. Figure 45 shows an amaryllis. It resembles
the iris in having the perianth adherent to the ovary and
it resembles the lly in having six colored divisions and
six stamens. The narcissus and daffodils have a crown
on the throat of the perianth. The daffodil is yellow with
a large yellow crown. The narcissus is white with a small
yellow crown. The snowdrop is white and without a
crown. A main thing we should learn in this lesson is the
intermediate character of the amaryllis family between
the lily family and the iris family.
LESSON: €XXXT.
The Grass Family.
The Gramineae.
The Gramineae include the wheat, oats, rye, barley,
timothy-grass, orchard-grass, blue-grass, foxtail, Indian
rice, or water oats, and Indian corn and many other sorts
204 Nature Study.
of grasses. A very large and most important order o
plants as our cereals belong to it and it furnishes the
chief food of domestic animals.
A good way to begin the study of this family is with
oats in the flowering season.
Find the central stem of the “‘head,”’ the axis of inflores-
cence; its several side branches; some of these are branched,
others not. Oats furnishes a good example of a panicle,
see page 173. See if each final branch or spikelet does not
bear two or three flowers. At the base of each spikelet
are two empty glumes. We call them glumes because
they are not quite opposite and they are a little below the
flower, otherwise we should call them an involucre. Is the
spikelet that bears these glumes and the flowers above it
flat? Find two more glumes for each flower, an outer,
larger one that encloses the flower and the smaller one on
the other side of the spikelet called the palet. Ii these
two glumes were alike and opposite we should doubtless
call them sepals; they are generally called the upper and
lower palets. Find inside of these the three stamens
growing distinct on the receptacle (hypogynous); the
pistil is made up of a top-shaped, hairy ovary and two styles
that are clothed with hair-like stigmas. At the base of
the upper palet, between its edges, find two very reduced,
bract-like scales called the lodicules. It is probable that
these bractlets are all that is left of the perianth of the
flower of the grasses. If this lesson is faithfully done and
is followed by a similar lesson with wheat and the cereals
and then with the larger grasses it will end in the ability
to become acquainted with the grasses; an acquaintance
that makes for one many friends for the grasses are found
everywhere. The Gramineae can be told by their hollow
stems with closed joints, their alternate two-ranked leaves,
the sheaths of which are split on the side opposite the blade,
and their hypogynous, solitary flowers in the axils of two-
The Pine Family. 205
ranked glumes. Corn should be studied as an interesting
variation, having the staminate flowers at the top, and
many pistillate flowers, as many at least as there are
grains afterward, on a spadix, the cob, and surrounded
together by the glumes, the husks.
In many parts the Indian rice may be studied to see an
“instance in which the pistillate flowers are above the
staminate. This arrangement favors cross-pollination from
another plant, since pollination is almost sure to occur
when the wind is blowing. I saw, August 3rd, 1903,
Indian rice from ten to fifteen feet high at English Lake,
Indiana. Experiments are being carried forward now
looking toward its cultivation for economic purposes.
LESSON CXXXII.
The Pine Family.
Contferae.
To this family belong the pine, spruce, arborvitae, fir,
tamarack, (hackmatack or larch) white cedar, hemlock,
yew, juniper and bald cypress. The leaves of the pine
are in clusters or bundles of from two to five and are ever-
green. The larch has its leaves clustered many in a fascicle,
and they are deciduous. The leaves of the spruce are
scattered singly over the branch and each has a short
brown petiole. Compare Lessons VI, VII and XXXIX,
Breures 7, 8, 9 and 64. The leaves of the hemlock are
scattered singly and have a green petiole. The leaves of
the fir are scattered singly, have no petiole but are attached
to the stem by a disc. Compare Lesson III, Figure 4.
The arborvitae has its leaves scale-like in four rows on
the stem; they completely cover the stem; the spray is
206 Nature Study.
flat. The common juniper has its awl-shaped leaves in
whorls of three; the red cedar has its scales awl-shaped
appressed to the stem, four-ranked, but the ‘sprayemre
roundish, not flat like arborvitae. The bald cypress, so
common on the margins of lakes and rivers and in the
swamps of Florida and sometimes cultivated in the North
has its leaves on a flat spray which it sheds together with
the leaves. As it grows in a few feet of water its roots
require some means of getting air. This is furnished by
the spongy knees which grow up from the roots and the
enlarged base of the trunk which is also porous.
The family name means cone bearers, in allusion to the
cones made up of many scales under which the winged
seeds, Figure 81, grow. |
LESSON CXXXIII
The Ferns.
Filices.
This order comprises the beautiful ferns which grow
everywhere in damp, shady places. The maiden hair fern
is the one known, perhaps, to most people. Its frond
stems are shining black; its botanical name is Adiantum
pedatum; the specific name pedatum is in allusion to the
mode of branching of the frond which is supposed to
resemble a bird’s foot. For the general characteristics of
ferns, see Lesson LX and Figures 94 to 100.
The spores on the under side of the leaves should be
sowed on damp soil in a flower pot under a bell glass or
fruit can and the growth of the fern watched. It should
be seen that fern fronds grow up from an underground
stem—a rootstock which also bears roots. Notice that
The Mosses. 207
the spores of the maiden hair fern are covered by the
reflexed margins of the frond. This covering is called the
indusium. Notice that the fruit dots often grow at. the
end of a comparatively large vein of the frond and that
the indusium is sometimes attached by a central stem
(peltate) to the frond; sometimes it 1s attached all along
one side. These are items which will help in the classifi-
Cariom of the ferns.
WESSON COCXXLy.
The Mosses.
The mosses carpet the damp shaded ground in early
spring; they also grow on rocks and trees and some of the
species grow where water trickles over a bank. If this
water is charged heavily with lime, formations of petrified
moss in large masses may be formed. Such formations are
common about Richmond, Indiana. Every one should
study the mosses enough at least to learn the difference
between what botanists call the sporophyte (spore bearing
plant) and the gametophyte (gamete bearing plant). The
gametes are the two cells, male and female, which unite
in sexual reproduction.
In the mosses the sporophyte consists of the long naked
stem which grows from the summit of the leafy moss plant
which is the gametophyte.
Sporophyte and gametophyte are of somewhat equal
size in the mosses; at least both can easily be seen. The
connection between them is slight. The dried sporecup
and its stem can easily be pulled out from the slight de-
pression it occupies at the top of the leaf-bearing moss,
the gametophyte.
In the mosses it is easy to understand the alternation
208 Nature Study.
of generations among plants. The microscopic spores
which are borne in large numbers in the sporecup at the
top of the sporophyte are scattered by the wind; when
they alight on damp soil or rocks or bark they begin to
grow and ultimately they produce not a sporophyte like
they came from but a gametophyte, a leafy moss some of
them, in most species male plants, and some cf them female.
These bear, in the rosettes at the ton of the stem, each in
its apporpriate cup, the male and female cells. When
rain or dew unites the heads of male and female moss
plants, the male cells swim across and find their way to
the female cells; one male cell unites with one female cell
and from the union a sporophyte grows up. In this
manner are produced in alternation gametophyte, gametes,
sporophyte, spores, gametophyte, etc.
Alternation of generations plays an important part in
both the plant and animal kingdoms; it cannot be studied
with any other material to better advantage than it can
with mosses. Among ferns the gametophyte, Figuie 98,
is so small that it is usually overlooked. Among our seed-
bearing plants it is so small it can only be studied with a
compound microscope.
There are many other families of plants which cannot
be noticed even briefly in a work like this. The following
are a few more that may be studied through the common
and well known representatives given with each:
Borraginaceae through Hound’s Tongue (sticktight).
Anonaceae through Papaw.
Fumariaceae through Dutchman’s Breeches.
Linaceae through Common Flax.
Rutaceae through Prickley Ash.
Vitaceae through Grape.
Sapindaceae through Buckeye, Maple and Box Elder.
Anacardiaceae through Sumach.
Calycanthaceae through Sweet Scented Shrub.
Plant Famulies. 209
Saxifragaceae through Hydrangea, Mock Orange, Cur-
rant and Gooseberry.
Crassulaceae through Stonecrop.
Hamamelideae through Sweet Gum.
Onagraceae through Primrose.
Cucurbitaceae through Gourd, Pumpkin, Squash, Musk-
melon, Watermelon and Cucumber.
Umbelliferae through Harbinger-of-Spring (Pepper-and-
salt), Wild Parsnip, Carrot, etc.
Cornaceae through Dogwood and Sour Gum.
Caprifoliaceae through Honeysuckle, Elder, Black Haw
and Weigela.
Rubiaceae through Galium (Bed Straw, Goose Grass).
Ebenaceae through Persimmon.
Asclepiadaceae through Milkweed.
Polemoniaceae through Phlox and Valerian.
Scrofulariaceae through Mullein, Butter and Eggs, Snap
Dragon and Speedwell.
Bignoniaceae through Catalpa.
Plantaginaceae through Plantain. Consult Lesson XXI.
Polygonaceae through Dock, Knotweed and Buckwheat.
Lauraceae through Sassafras.
Commelinaceae through Spiderwort.
Araceae through Indian Turnip, Skunk Cabbage and
Calamus.
GLOSSARY
Adherent, applied to the calyx, etc., when growing fast to the ovary.
Alae, Side petals of a papilionaceous flower.
Ament, 173. A pendulous spike.
Androecium, the stamens taken together.
Anther, Pollen-container at top of filament.
Apetalous, without petals.
Auriculate, with ear-shaped appendages.
Bract, a reduced leaf, 66.
Bulb, a fleshy scaled underground leafbud, 73.
Calyx, the outside whorl of a flower. -
Carina, the lower united petals of a papilionaceous flower.
Carpel, “‘a simple pistil or one part of a compound pistil.”’
Catkin, Same as ament, 173, apendulous spike.
Cleistogamous,.a term applied to flowers that do not open.
Complete, applied to a flower containing the four whorls.
Convolute, overlaping with one edge in and one out.
Corm, the:solid enlarged fleshy base of a stem.
Corolla, the second whorl of floral leaves.
Corymb, 173.
Determinate, applied to flower clusters blooming first at the center
or top.
Diadelphous, applied to stamens united into two sets by their
filaments. .
Diandrous, Having two stamens.
Dicotyledonous, Having two seed-leaves.
Epigynous, on the pistil.
Equitant, applied to enfolding upright leaves like those of blue flag.
Extrorse, opening outward.
Feather-veined, veined like a beech leaf. Same as pinni-veined,
200.
Filament, the support of the anther in a stamen.
Free, said of the flower whorls when they are separate.
Gamete, 207, 160.
Gametophyte, 207.
Gamapetalous, petals united.
Glumes, the chaffy bracts of the grasses.
Gynoecium, the carpels taken together.
Figad, 173:
Glossary. 211
Hypogynous, under the gynoecium. Said of parts growing on the
receptacle.
Imperject, said of a flower lacking stamens or pistils.
Incomplete, said of flowers lacking some whorl.
Indusium, the covering of sori in ferns. Figs. 95, 96, 100.
Inflorescence, flower arrangement on the stem.
Introrse, opening inward.
Involucel, a secondary involucre.
Involucre, a whorl or whorls of bracts around a flower or flower
cluster.
Irregular, Having the parts of the same whorl unlike, 189.
Legume, the fruit of the Leguminosae—a bean, 189.
Ligulate, Strap shaped. Like the corolla of dandelion.
_Lodicules, 204.
Monocotyledonous, with one cotyledon.
Monadelphous, united by filaments into one group, 188.
Ovary, the seed bearing, lower part of the carpel.
Pales, the thin, upper, hyaline chaff of the grasses.
Palmately Veined, veined like a sugar-maple. Fig. 22.
Panicle, 173.
Papillionaceous, said of a corolla like the bean and pea have
Parallel Veined, veined like corn. Fig. 27.
Peduncle, a flower stalk.
Peltate, umbrella shaped.
Perfect, said of a flower having stamens and pistils.
Pertanth, a term fcr both calyx and corolla.
Perigynous, around the gynoecium; said of petals and stamens
when they grow on the calyx.
Persistent, not falling off.
Petal, one of the parts of the corolla.
Petiole, the stem of a leaf.
Pinnately, veined like the elm, Fig. 26, or compound like Fig. 25.
Pistil, ‘‘the seed-bearing organ of the flower.”’
Polygamous, bearing pertect, fertile and sterile flowers.
Polypetalous, having more than one petal.
Raceme, 173.
Rootstock, 206, Fig. 53.
Sepal, one of the parts of the calyx.
Sessile, without a stem.
Silicle, a short pod like shepherd’s purse has.
Silique» a long pod like mustard has.
Sort, the fruit dots on underside of fern leaves, 89, 90.
212 Nature Study.
Spermatophyte, a seed-bearing plant.
Spike, 173.
Sptkelet, 204.
Sporangium, a spore cup. Figs. 97, 105.
Spores, 207, 89,,90.
Sporophyte, 207.
Stamen, one part of the androecium.
Stigma, the topmost, naked part of the pistil.
Style, it connects the stigma and ovary.
Symmetrical, said of a flower with same number of parts in each
whorl.
Syngenicious, applied to stamens united by their anthers, 191.
Thyrse, a thick much compounded panicle, 173.
Unsymmetrical, said of a flower with differing numbers in its whorls.
Valvate, edges meeting. .
Vexillum, the large uppermost petal of the leguminosae, as the
bean.
INDEX.
Abutilon, 24, 25,* 26.
Agave, 109.
Alga, 43.
Alternation of Generations,
NOV
Amaryllis, 38, 39, 203.
Ament, 173.
Anemophilous Plants, 48.
Animals and Plants, 148.
Annual Herbs, 50.
Antheridium of Moss, 159, 160.
Anthrax, 142.
Ants, 44.
Apple, 9, 13, 28, 75.
Archegonium of Liverwort,
160.
Asexual Reproduction, 152.
Aspen, 16.
Bacteria, 141.
Balm of Gilead, 16.
Bark, 122, 125, 128.
Bean, 40, 79.
Beech, Leaf-Arrangement of,
27 28.
Beech Leaf, Petiole of, 27.
Beech Tree, 1, 2, 13.
Berberidaceae, 183.
Biennial Herbs, 51.
Birch, 22, 28.
Bracts, 66.
Branches, Horizontal, 12, 13.
Branches, Vertical, 12, 13.
Branching, Deliquescent, 8.
Branching, Excurrent, 6, 7.
Branchlets, Pendant, 11, 60.
Broom-Corn, 35.
Bryant, Wm. Cullen, Quota-
tion from, 127.
Buds 57, 58.
Bud Scales, 58, 71.
Bull Scales, 72, 73.
Burns, Robert,
from, 89.
Burdock-Bur, 92.
Quotation
Butterflies, 41.
Cane, 35.
Caryophyllaceae, 187.
Cathkin. 173;
Cedar, 9.
Cell, The 151.
Cherry Tree, The Wild, 3, 9.
Chestnut-Bur, The, 92.
Chestnut Leaf, The, 18.
Chlorophyll, 146.
Cleistogamy, 45.
Climate, 49-62.
Clover, 26. 132.
Cockle-Bur, 92.
Compass-Plant, 16.
Compositae, 191.
Complete Flower, 32.
Coniferae, 205.
Convolvulaceae, 194.
Corny o4. 110,
Corn and Soil, 22, 23,
Corymib, 173.
Creeper, Virginia, 14.
Cross-Pollination, Experiments
in, 46.
Crowfoot Family, 182.
Crow-Roost, 94.
Cruciferae, 185.
Cupuliferae, 200.
Currents of Water, 93.
Cut-Leaved Maple Leaf, 17.
Dandelion, Pappus of, 74, 84,
86.
Datta, 137.
Deciduous Forests, 4, 54.
Desert Plant, 109
Diatoms, 104, 105.
Dioecious Species, 36.
Dispersal of Seeds, 82-100.
Eimtiree,) hes Silo:
Elm Leaf, 19.
Entomophilous Plants, 47.
Epilobium, 38.
Erigenia Bulbosa, 158.
*When the paging is given in this type an illustration will be found.
214
Evergreen Leaves, 55, 56, 57.
Excurrent Branching, 6.
Felices, 206.
Bern, 89°90) 121, 206.
Fern, 89, 90, 121.
Fern Leaf, Section of, 54.
Fibro-Vascular Bundle of Sm1i-
lax, 114, 115.
Fibro- Vascular Bundle of Corn,
116.
Fibro-Vascular Bundle of Ger-
anium, 117,118.
Fibro-Vascular Bundle of Fern,
121
Fire-Weed, 38.
Fir-Tree, The; 6, 7,
Food, 135.
Forestry, aise
Fruit and Seed-Dispersal, 94.
Fuel, 137.
Genera, 178.
Geranium, The Cross-Section
Ol a Stemyor, 175) 1So:
Ginkgo Leaf, 19.
Goethe, 40, 152.
Gramineae,, 203..
Grass Family, 203.
Greenbrier Leaf, 19.
Growth, 164.
Hazelnut, 13.
Head, 174.
Heart-Wood, 122, 124.
Biedge; 13:
Horse-Chestnut Leaf, 18.
Hyacinth, Water, 153.
Hydrophytes, 101.
Inflorescence, 172
Infusorial, Earth, 105.
Insects and Pollination, 40, 41.
Indaceae, 202.
Juglandaceae, 198.
Katahdin, Mt., Birches Grow-
ing on, 22)
Koch, Robert, AD.
Labratae, 193.
Land Plants oie
Larch, European, 11.
Leaf, The, 62-77.
Leaf-Arrangement, 28.
Leaf, Cross-Section of, 76.
Leaf, Foliage, 62.
Leaves, Compound, 18, 19.
Index
Leaves, Evergreen, 55.
Leaves, Effect of Shadow on,
19.
Leaves, Shapes of, 17, 18, 19.
Leguminosae, 189
Lenses, 170.
Lettuce, Prickley, 16.
Lichen, ‘43.
Light, ioe
mine ‘Leaf, 19.
Lily, 73.
Linden Seed, 82.
Live Oak, 61, 62.
Lumber, a3u0
Magnoliaceae, 183.
-Malvaceae, 188.
Maple Spray, 15.
Measuring a Tree, 5, 6.
140.
Microscopic Plants, 104.
Mint Family, 193.
Mistletoe, 140.
Mountain-Ash Leaf, 18.
Monecious Species, 33, 35.
Morning-Glory, 14, 194.
Mosses, 207.
Moths, 41.
Mulberry, 36.
Mullein, 20, 215552.
Mushrooms, 144, 145.
Mustard Family, 185.
Nettle Family, 197.
Night Shade Family, 193.
North Indiana Field, 101, 103
Norway Spruce, 11 12, 60.
Nostoc, 154.
Nuts, 95.
Oak Family, 200.
Oak Leaves, 17.
Oedogonium, 158.
Onion, 23.
Orchid, 41, 42.
Oxalis 26.
RalinapoO ote
Palmetto Brushes, 116.
Pampas-Grass, 99.
Panicle, 173.
Papaveraceae, 184.
Pappus, 74, 84, 86, 87.
Parasitic Plants, 140)
Medullary Rays, 119, 120, 123,
Morphology of the Laef, 62-77.
eas
Index. 215
Pasteur, 143.
Pea, Garden, 77.
Pea, Sweet, 78.
Perennial Herbs, 53.
Persimmon Tree, 59.
Petals, 67.
Petiole, Behavior of, 13, 14, 15.
Phylolaccaceae, 194.
Pilobolus, 97.
Pine, 10, 19, 29, 205.
Pine Leaf, Section of, 56.
Pine, Pitch, 9, 10.
Pink Family, 205.
Pistils, 70:
Pistillate Flowers, 33.
Plankton, 104.
Plant Societies, 101, 102-113.
Pianabain, 37, 198.
Poke-weed Family, 194.
Pollen, 32, 33, 34.
Pollination, 32-48.
Poplar, Carolina, 16.
Poplar, Lombardy, 14, 16.
Portulaccaceae, 187.
Protandry, 38. ‘
Protogyny, 37.
Protoplasm, 151.
Pulse Family, 189.
Pumpkin Vine, 14.
Pusslane, 110, 111, 187.
Quarter-Sawed Oak, 123.
Raceme, 173.
Ragweed, 93.
Ranunculaceae, 182.
Red-Oak Leaf, 17.
Respiration of Plants, 150.
Rings of Growth, 120, 122.
Rose Leaf, 19.
Rose Family, 180.
Rosette Leaf Arrangement, 20,
PA
Reet, 130; 131.
Salicaceae, 201.
Saprophytes, 144, 145.
Sap-wood, 122.
Scott, Sir Walter, Quotation
fom, 16;
Seeds and Spores, Size of, 89.
Seed Dispersal, 82-100.
Seeds that Cling, 91, 92, 93.
sepals, 67.
Sexual Reproduction, 156, 157.
Shapes of Leaves, 17, 18, 19.
sleep of Platts, 24, 25, 26.
Smartweed Embryo, 162.
Smilax, 114.
Soil, Influence of, 22, 23.
Solanaceae, 193.
Solomon’s-Seal, 53.
Southey, Robert, Quotation
froma; 65.
Spanish Needle, 91, 92.
Species, 178.
Sperms of Moss, 160.
Spike; 1:73.
Spines, 65.
Spirogyra, 147, 157.
Sporangium of Fern, 96.
Spore Dispersal, 97.
Spores and Seeds, 89.
Spring Flowers, 127.
spruce, Norway, 11, 12, 13, 60.
Stamens, 69.
Staminate Flowers, 33.
Starch, 134.
Stem, Influence of Climate
Sha ool One 22.25%
stem, Main Duty of, 21.
Stems, 114-129.
Stomata, 54, 56, 107.
Storms, 49.
Streptococcus, 155.
Struggle for Existence, 80.
Sweet Pea, 78.
Sycamore, 19.
Sycamore-Maple Leaf, 18.
Symboisis, 42, 43, 95.
Table of SeedjDispersal, 100.
Tamarack. 1129.
Teasel Family, 190.
Tendrils, 77-79.
Thistle, 88, 191.
Transpiration, 64.
Tumble Weed, 98.
Twinleaf Embryo, 163.
Twining Plants, 79.
Umbel, 173.
Urbccaceae, 197.
Uses of Plants, 134-139.
Vetch, 133.
Violet Family, 186.
Walnut, 98, 198.
Walnut Tree, 3, 4, 5.
Water, Currents of, 93.
216 Index.
Water Hyacinth, 153. Whittier, John Greenleaf, The
Water-Lily, White, 105, 106, Palm, 138.
184. Xerophytes, 109.
Water Plants, 101. Yeast, 155.
Willow Family, 201. Yellow Chestnut Oak, Leaf of,
Wind, Influence of, on Plants, V7.
60, 61, 62. Young Plants, 166.
Winged Seeds, 82, 83.
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