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Laboratory Outlines 


General Botany 







Professor of Botany, and Head of the Department of Botany 
Ohio State University 

columbus, ohio 
Published by the Author 





For the Elementary Study of 
Plant Structures and Functions 
from the Standpoint of Evolution 



Professor of Botany and Head of the 
Department of Botany- 
Ohio State University 



19 15 





SEP 23 !9! c 


The series of outlines presented in the following pages was first published 
in the Journal of Applied Microscopy. The outlines as here presented have 
undergone various additions and alterations in order to bring them up to date and 
to give a more perfect view of the plant kingdom as a whole. Among other things, 
an attempt has been made, so far as possible, to use a reasonable terminology. 

It is presumed that the course can be covered practically as given in one 
college year with three laboratory periods of two hours each a week. 

The course is intended for the freshman or sophomore year. The student 
should have a fair knowledge of language, mathematics and drawing as well as 
the foundations of chemistry, since the pursuit of the biological sciences calls 
for considerable independent effort, skill of manipulation, and ability to reproduce 
and describe what is seen. 

In case a briefer course is necessary a considerable number of types or parts 
of outlines can be omitted without seriously breaking the continuity of the subject. 
x-\ccording to the author's views any thoro course should include at least the follow- 
ing, either complete or in part : 

(b), (c), (d), (/), (g), LXXVI, LXXVIII.-LXXX, LXXXII, LXXXV.- 

Some of the types which cannot be given in the laboratory period may be 
used for class demonstrations. 

The appendix on microtechnique will be found useful where it is possible to 
have students prepare some of their own slides. The methods given are for the 
most part such as have been thoroly tested in the class room by the author himself. 

In this fourth edition a number of changes have been made in order to include 
recent advances in botany and related subjects. J. H. S. 



Coarse adjust 
ment: Rn k 
and pinion 

Fine adjustment: 
Continuous Safety 

Dustproof triple nose- 
piece with objectives 


Plate I. Compound Microscope. Bausch and Lomb Microscope FFS8. 


The following outlines are designed for those who have access to little appa- 
ratus_ outside of a good microscope. The course will probably be more than 
sufficient for the time usually alloted in most of our colleges and universities 

Whatever may be the opinion in regard to the elementary course of botany, 
t is the writers belief that the general college or university course should be 
largely carried on with the use of the compound microscope; and should cover 
m a general way, the whole plant kingdom, so that the idea of the evolution of 
plants and their natural relationships will be made prominent. The student 
should have a general grasp of the plant kingdom as a whole, and to accomplish 
such a result a large number of forms must be studied. Along with this general 
idea, a considerable knowledge of morphology and physiology may be acquired 
smce the study should have to do largely with living material. The course should 
cover a year with at least two laboratory periods of two hours each, a lecture 
and a quiz with assignments from a suitable text-book. After such a course the 
student is well fitted to take up the various departments of advanced work H 
will have acquired a sufficient knowledge of biology to carry on intelligently, 
whatever specia studies he may later choose to pursue, as, anatomy, histology 
cytology, physiology, ecology, taxonomy, genetics, or advanced work in special 

It is often supposed that to accomplish good work it is necessary to have 

afford rl eXPe T e ^^"r' and aU the fadlities Which our leadin §" diversities 
afford There is however, a large amount of work that may be done by those who 

™ JT Ti ^ - eqUipment ' and substantial progress may be made in the 
general facts of the science with little besides what is indicated below 
lhe student should have the following equipment: 

1. A good text-book of botany for general reading 

2. A compound microscope, like the Bausch and Lomb FFS 8 , having a double 

nose-piece with 16 and 4 mm objectives, and ox and 12.5x eye-pieces- 
the Spencer microscope No. 44 with 16 and 4 objectives, and 6x and 
10x eye-pieces; or the Leitz microscope Stand II. U. with objectives 
3 and 7 and eye-pieces II. and IV. The same stands with complete 
substage and triple nose-piece are preferable if one can afford to 
pay the difference in price. With the Bausch and Lomb stand the third 
objective may be the 48 mm, and this may be used instead of a dis- 
sectmg microscope. 

3. A number of slides and cover-glasses. 

4. A good hand-lens or a dissecting microscope. In case the microscope has a 

triple nose-piece it should be fitted with a 48 mm objective. 

5. A good note-book with note paper and smooth drawing paper and also 

some bnstol board drawing paper for the finer drawings. (See "The 
Laboratory Note Book" in appendix.) 

6. Loose writing paper for making temporary records and calculations 

7. Two good lead pencils, a No. 3H and a No. 6H. It is also desirable to 

have a bottle of India ink or Higgins' eternal ink and crow-quill or 
other suitable drawing pen so that the drawings may be finished in ink. 


8. The following instruments are necessary : 

a. A pair of forceps. 

b. Several medicine droppers. 

c. Some needles set in wooden or bone handles. 

d. A scalpel. 

e. A razor. 

/. Dishes, watch glasses, butter dishes, and bottles of various sizes. 
g. Plenty of clean cotton rags and some paper blotters. 

9. The following simple reagents will be needed on the table : 

a. A small bottle of 50 per cent, aqueous solution of glycerin. 

b. A bottle of distilled or pure, boiled water. 

c. Iodin solution. 

d. Salt solution, saturated aqueous. 

e. A bottle of ninety-five per cent, alcohol. 

If a greenhouse is not near, a window garden and aquarium become indis- 
pensable. Water plants kept in glass jars with some small water animals, as 
water snails and water beetles, will usually grow with little or no attention. In 
most cases the jars should be covered. 

Many of the specimens may be preserved in various preserving fluids, and 
some may be dried. These will be found very convenient in case fresh material 
cannot be obtaained when desired. Microscopic plants may be preserved in water, 
in homeopathic vials, provided a drop of carbolic acid is added ot each bottle of 
material. Plants like mosses, liveworts, fleshy fungi, stems, roots, rhizomes, etc., 
may be preserved in 70 per cent, alcohol. The ordinary filamentous algae are 
usually well preserved in copper salt solution. (See appendix.) Myxomycetae 
in the 'fruiting stage, woody fungi, lichens, some liverworts and many other plants 
may be kept in a dry condition in ordinary paper boxes. 

Useful pamphlets on the use and care of the microscope are furnished by 
the Bausch and Lomb Optical Co., of Rochester, N. Y., and the Spencer Lens Co., 
of Buffalo, New York. 

The following suggestions are offered especially for the benefit of laboratory 
students, altho most of the directions will also be useful to the amateur micro- 
scopist working at home : 

The microscope must always be handled below the stage and never lifted by 
any part above the stage (unless one has an instrument of the new type with a 
rigid arm), otherwise the fine adjustment may be injured. The microscope is a 
very delicate instrument. It must not be inclined for general work, as temporary 
mounts' will not stay in the field unless the stage is horizontal. While working, 
the observer should keep the side of the microscope with the coarse and fine 
adjustments toward him. The microscope is hot to be moved about to obtain the 
light. This can be obtained from almost any direction by adjusting the mirror 
properly. Great care must be taken so as not to run the objective down into 
the diaphragm or onto the cover-glass and slide. The lenses of the microscope 
must not be touched with the fingers. They must be wiped only with a very 
clean, soft, cotton cloth or with lens paper. They must be kept scrupulously 
clean. The student should learn the different combinations of low and high 
powers immediately and how to change from one to the other without difficulty. 

The wiping rags should always be clean, and the slides and cover-glasses 
must be kept scrupulously clean. The student should learn at the beginning how 
to clean the cover-glasses without breaking them To do this, take the cover- 


glass, moistened in water or alcohol, in the rag between the thumb and forefinger 
and hold it at the edges between the thumb and forefinger of the other hand. 
In making a mount air bubbles are to be avoided. To accomplish this, after 
the object has been placed on the slide and covered with a drop of water, hold 
the cover-glass at the edges between the thumb and forefinger and bring it 
down obliquely onto a needle held in the other hand, and then withdraw the 
needle gradually. The cover-glass will then settle down on the object sur- 
rounded by water. Xo water or other reagent must be on top of the cover-glass. 
If too much water has been put on the slide it may be removed with blotting 
paper. If the study of a good specimen cannot be finished in the given time, it 
may be preserved for a number of days by running a little fifty per cent, glycerin 
under the cover-glass. Reagents cost money, and are not to be poured out like 
water. The same is true of the material for study. This is often difficult to 
obtain and should be used with economy, and all good surplus material returned 
to the receptacle from which it was obtained. 

All objects studied are to be carefully figured and described. The drawings 
may be outlined with the 3H pencil and then finished with the 6H. If time is 
at hand, the drawing may be finished in India ink with a fine drawing pen. 
Learn how to keep the pencils sharpened to a fine point. After sharpening with 
the knife rub the point smooth on a piece of paper. The drawings are to be 
placed only on the front side of the drawing paper. The notes may be written 
continuously on both sides of the note paper, but are always to be taken down 
in ink. The plates containing the drawings should be numbered in Roman figures 
at the top, and the name of the plant or object written at the bottom. The 
separate drawings on the plate may be numbered in Arabic figures, and a proper 
record of them is to be kept in the notes. The notes on each plant may be 
numbered the same as the plate containing the drawings to illustrate it. The 
drawings should not be crowded, and the number should always be written below. 

The diameter of the field (the white disk visible when looking into the micro- 
scope) is usually about eight inches (two decimeters) when projected onto the 
table. Learn to do this by looking with one eye on the table beside the micro- 
scope and with the other into the tube. In this way the magnified image may be 
directly measured. The actual diameter of the area covered can easily be 
determine for the low powers by examining a millimeter rule. Learn to keep 
both eyes open when taking only ordinary observations in the microscope. Be 
sure to use both eyes, else one will be trained for more acute vision than the 
other. Make the drawings of small objects of the right proportion, and the 
actual size magnified. The larger ones may have to be reduced to bring them 
onto the paper. If the object has a definite relation to environment do not 
draw it upside down. It must also be remembered that motions are magnified 
as well as the objects themselves. 

Absolute regard for the truth is the first requirement in scientific drawings 
and descriptions, and the qualities required for good work are accuacy, cleanli- 
ness, patience, skill, pesistency, good judgment, and logical ways of thinking. 
The drawing should be exact in all details ; the sketches may be more or less 
diagrammatic. The notes should be written in the best English at the command 
of the student. The facts should be stated in concise but complete declarative 
sentences, without rhetorical ornamentation. The observations must always be 
recorded at the time when they are taken. One's memory should not be trusted 
very much in recording scientific facts. 



Finally, it must be remembered that one of the first things to be accom- 
plished is to educate the hand for delicate manipulations. And it is also well to 
keep in mind that scalpels and razors are not intended for sharpening lead pen- 
cils or cutting the table, that oculars, and objectives are never to be dropped, 
that stoppers should not be laid down on the bare table, that books and note-books 
are not to be soiled by the wet and dirty fingers, that bottles and tumblers of 
water are not to be overturned, and that one should understand the objects studied 
before attempting to draw or describe them. 











Plate II. Diagram of the Plant Phyla. 


I. Phildtria canadensis (Mx.). Waterweed. 

This is a very common plant growing submerged in ponds, creeks, etc. It 
will grow well for a long time if simply pulled up and placed in a covered glass 

1. Carefully pull off a few young leaves and mount on a slide with a drop 
of water and a coverglass. Examine under the dissecting microscope. Sketch the 
entire leaf under low power of the compound microscope. Make the drawing 
about five inches long. Describe the shape, margin, color, midrib. Are there 
any other veins? 

2. The leaf is composed of cells. How many across the leaf? How many 
lenthwise? Is the leaf more than one cell in thickness? About how many cells 
on the upper surface? 

3. Cut cross sections with the razor by holding some leaves between pieces 
or strips of common carrot either fresh or preserved in alcohol. How many 
cells in thickness, on the average? 

4. Suppose the leaf averages three cells in thickness, about how many cells 
m the entire leaf? 

5. Under high power, draw several adjoining cells, carefully showing details. 
(Draw the walls as represented in Fig. 1). What is the general shape of the 
cells? The contents of a cell are protoplasm and sap or water. There is usually 
some dead food material present. 

Fig. 1. — Cell Walls of Philotria. 

6. Draw a cell showing the nucleus. Notice that the protoplasm is made up 
of cytoplasm, nucleus, and chloroplasts. Where is the green coloring matter? 
What is the color of the rest of the leaf? The green coloring matter is chlor- 
ophyll. What is its use? Estimate the number of chloroplasts in a single cell. 
How many would there be in the entire leaf? How does a green plant get its 



7. Movement of protoplasm. Describe the motion. Do not be satisfied until 
the rotation is very striking. The room and water should not be too cold. Does 
the protoplasm rotate in the same direction in all of the cells? How many 
seconds does it take for a chloroplast to make the round? Does the nucleus 
move in the cell? The active agent in the movement is the cytoplasm. The 
cytoplasm does not move from one cell to another. 

8. A cell is a small mass of protoplasm, in typical plants usually differen- 
tiated into cytoplasm, nucleus and plastids, and surrounded by a cellulose wall. 
The cell is the unit of plant structure. In some of the lower plants no nucleus 
has been discovered, and in many plants the plastids are absent. 

9. Treat a fresh leaf with alcohol. Does the protoplasm still move? What 
effect does the alcohol have on the chlorophyll? Treat a fresh specimen with 
salt solution. What takes place? Explain the cause. Ask for an explanation 
or study the subject of plasmolysis in a text-book. These cells have a vacuole- 
(water chamber) inside of the protoplasm and are normally in a turgid con- 
dition. Treat the specimen in alcohol with iodin solution. Notice the nucleus 
and nucleolus. Notice the large starch grains stained dark blue inside of the 

10. Ecological note. Does this leaf have stomata? How is it adapted to 
its environment? 

11. Allium cepa L. Common Onion. 

1. Pull off the inner and the outer epidermis from a living scale of an onion. 
Mount in water. Compare the cells of the two specimens under low power as 
to shape, size, and contents. Notice the wall lined with cytoplasm ; also the 
nuclei. Draw a number of adjoining cells from the inner epidermis. Notice the 
absence of chloroplasts. 

2. Under high power, draw a single cell showing the wall, cytoplasm, and 

3. Study the movement (streaming) of the cytoplasm. This can usually be 
seen best at the ends of the cells. Notice t'he fine strands of cytoplasm stretching 
across the cell or across the corners of the cell thru the large central vacuole. 
Make a diagram of a cell showing the position of these streams, and indicate the 
direction of the flow by means of arrows. 

4. Treat with a drop of iodin solution after killing the cells in alchool. 
Make a careful drawing of the nucleus under high power showing the nucleoli. 
What is the normal number of nucleoli for each nucleus in these cells? Is the- 
number constant? Are there any starch grains present stained blue by the iodin?' 

5. Why do the scales of the bulb not .have chlorophyll? 

III. Tradescantia sp. Spiderwort. 

The flowers of almost any of the wild or cultivated species of spiderwort 
will be found suitable. Rhoeo discolar Hance, easily grown in greenhouses and 
window gardens, will also do very well. It blooms almost continuously. 

1. Study the stamen hairs. With a scalpel cut off some of the stamen fila- 
ments containing the young hairs. Mount in water. Be careful to get the hairs 
wet, but do not injure them. Under low power, notice that the hair is made up> 
of a chain of cells. Draw. 


2. Study a single cell under high power. Observe the position of the 
nucleus ; the cytoplasm, filled with small granules, lining the cell wall ; and the 
large vacuole filled with water thru which granular strands of cytoplasm stretch. 

3. Study carefully the streaming motion of the cytoplasm. Are the streams 
constant or can you see changes going on in their position? Do some of the 
strands disappear entirely? Watch the position of the nucleus for some time and 
describe its motion. Select one that is suspended in the central part of the cell. 
Make a large, careful sketch of a cell showing the streaming to good advantage. 
Plot all the moving streams visible by focusing up and down, and indicate by 
means of arrows the direction of the movement. 


IV. Pleurococcus vulgaris (Menegh..). Phylum, Gonidiophyta. Class. 
Pleurococcese. Order, Pleurococcales. Family, Pleurococcaceae. 

This is a unicellular green alga which very commonly forms a green, pow- 
dery layer on the bark on the north side of trees, on fences, rocks, etc., and is 
available at any time of the year. 

1. Scrape off some of the green powder from a piece of moist bark and 
mount in water. Pick out one of the largest single plants and draw under high 
power, showing the thick cellulose wall and the chloroplasts. 

2. Notice that the cells (individuals) have a tendency to hang together for 
some time after division. Study and draw aggregates or colonies of two, three, 
four, and eight cells still united. In how many directions do the cells divide? 
Describe the color, shape, and habitat of the plant. How does it get its food? 
Notice that it must be exposed to long periods of drouth. Do not forget to look 
for this plant (and as far as possible all others studied) in it* usual habitat out 
of doors. 

-o-o ^o-o 



Fig. 2. — Life Cycle of Pleurococcus. 

3. Its life cycle may be stated as follows : increase in size of the cell, division 
of the cell into two, separation of the daughter cells. Taking no account of the 
fact that the cells hang together for some time after division, make a diagram 
in the notes illustrating this as indicated in Fig. 2, a. 

4. Make a diagram showing the ancestors of one individual for ten gen- 
erations. See Fig. 2, b. 

5. Make a diagram showing the descendants of one individual for ten gen- 
eraitons . Use an entire page of note paper. See Fig. 2, c. 

6. Note. All plants and animals, whether high or low (except cenocytic 
forms) are single cells in the first stage of their life. Therefore, in the higher 
forms, the egg or spore also passes thru the two, four, etc., celled stages, and in 
these first stages the cells may also represent a loose aggregate or colony, since 
in many cases, if the cells are separated from each other by artificial means, two. 



or more plants or animals may be obtained from the egg, which would otherwise 
have produced only one individual. Pleurococcus shows how it is possible for 
a plant to pass from a unicellular condition to a colony, and from the condition 
of a colony to a multicellular plant. By what means could this be accomplished? 
The mechanical reason for the division of one of these cells may be dependent 
on the following facts : All food and waste material must pass thru the wall. 
Now the surface of a sphere is equal to tt D 2 and the volume is equal to I t D 3 , 
therefore, as the sphere increases in size, the surface continues to become less 
in proportion to the volume. How could a cell increase indefinitely in size and 
still keep the surface and volume in about the same ratio? What disadvantage 
or limit would there be to such a process? These plants have potential immor- 
tality, i. e., they do not grow old and die, except by accident. Natural death of 
an organism appears to be an acquired character. This plant, with a number of 
others to follow, is unicellular and without sexuality. It belongs to the lowest 
sub-kingdom of plants, which for convenience may be called the Protophyta. 

V. Merismopedia sp. Phylum, Schizophyta. Class, Cyanophyceae. Order, 

Chroococcales. Family, Chroococcacese. 

This organism can usually be found in the sediment of creeks, ponds, or 
lakes, especially in shady places where there is some decaying vegetable matter. 

1. Mount some of the sediment and examine under high power. Look for 
minute, blue-green, more or less rectangular plates of cells. Find colonies of 
various sizes, select a perfect one and draw, showing the arrangement of the 

2. In how many directions does cell division take place? How does the 
colony break up into smaller pieces? Such a flat layer of cells is called a super- 
ficial aggregate. Neither plastids nor nuclei are visible in these cells. The nuclei 
are very small. The bluish color is due to the presence of a peculiar coloring 
matter, phycocyan, in addition to the chlorophyll. Notice the gelatinous nature 
of the cell wall. Write a careful description of the plant. 

VI. Filamentous Blue-green Algae, (a) Lyngbya sp. Class, Cyano- 
phyceae. Order, Oscillatoriales. Family, Oscillatoriaceae. 

The species known as Lyngbya wollei Farl., which produces large brownish- 
black masses in rivers and ponds, or any other large species, may be used. A 
large species, appearing like a brown or black slimy layer, quite common in 
greenhouses and other moist situations, is also very good for study. This form 
can be kept indefinitely in a moist jar of earth. 

1. Mount a small mass of the slimy material in water, and study under low 
power. Draw several of the greenish-brown threads or filaments showing how 
they are interwoven. Notice the disk-like cells which make up the filament. De- 
scribe the general character of these plants. 

2. Under high power study a single filament. Draw part of a filament, show- 
ing the end cell. Why is the end cell more or less hemispherical and the others 
disk-shaped? Notice the dark granules. Where are they situated? Notice the 
thick sheath surrounding the cells. Draw a single cell, showing details as 
accurately as possible. 

3. In how many directions do the cells divide? Where and how does cell 
division take place? A filament like this is called a linear aggregate. 


4. Reproduction. In old filaments look for the development of hormogones — 
short pieces of a number of cells broken loose inside of the sheath. Draw and 
describe. How do the hormogones escape from the sheath? 

(b) Oscillatoria sp. Family, Oscillatoriaceae. 

Any of the minute, bluish-green forms which produce slimy, membranous 
layers in ponds, rivers and creeks may be used. They may be kept for an in- 
definite time in a covered glass jar of water. 

1. Mount a small flake in water, study under high power, and draw several 
of the slender filaments. There is no definite sheath present. Describe the color, 
shape of cells, and cell contents so far as they can be seen. Are the two ends 
alike? Compare as to size, etc., with Lyngbya. Draw a single cell. 

2. Study the reproduction. Compare with the method of reproduction in 

3. Make a careful study of the movement of the filaments. To get good 
results the plants should first be placed for some time in direct sunlight and the 
water should not be cold. Describe the movement. Why can these plants move 
more actively than the Lyngbyas? 

(c) Nostoc commune Vauch. Class, Cyanophyceae. Order, Nostocales. 
Family, Nostocaceae. 

This plant is common on damp ground in meadows, pastures, hillsides, etc. 
After a rain it appears as dark green gelatinous wrinkled or lobed masses. It 
may be kept for an indefinite period and will be in good condition after soaking 
in water. 

1. Describe the colony, noting its size, shape, and color. Draw. 

2. Mount and under low power note the general arrangement of the fila- 
ments. Look for the limits of the thick gelatinous wall in favorable plants. 

3. Under high power note the two kinds of cells composing the filament, 
ordinary cells and heterocysts. Why are the filaments so crooked? Draw a fila- 
ment showing both kinds of cells. 

VII. Beggiatoa alba (Vauch.). Phylum, Schizophyta. Class, Schizo- 
mycetae. Order. Desmobacteriales (Filamentous Bacteria). Family, Beggiatoaceae. 

These plants are usually very abundant in sulfur springs and in shady places 
in ponds and stagnant water where decaying vegetable matter is present. Beg- 
giatoa may be kept for years in a covered glass jar filled with water, provided 
there is a layer of decaying vegetable seOiment in the bottom. 

1. With a medicine dropper take up some of the black sediment containing 
Beggiatoa, mount, and examine under high power. Study the slender, more or 
less hyaline filaments, and draw one carefully. Draw a single cell showing the 
large sulfur granules. No chlorophyll is present. Describe the plant in general. 

2. Study and describe the movement. Do the sulfur granules move in the 
cell? How many seconds does it take for the tip of a filament to travel from 
one side of the field to the other? 

3. How does this plant obtain its food, and upon what does it live? How 
different in this respect from Pleurococcus? To what physiological group does 
Beggiatoa belong; holophytes, saprophytes, or parasites? 

Xote — These plants are intermediate between the blue-green algae and the 
bacteria. What relation is there between th lack of chlorophyll and th saprophytic 


VIII. Bacteria. Class, Schizomycetse. Order, Bacteriales. 

There are three common families of bacteria : 

Coccacece, Spherical Bacteria, containing the genus Micrococcus and others. 
Bacillacea:, Rod Bacteria, containing the genus Bacillus and others. 
Spirillacece, Spiral Bacteria, containing the genus Spirillum and others. 

To obtain Bacilli, make a hay infusion by boiling ordinary dry hay for 15 
minutes. Keep in a sterilized covered dish for several days. Also boil some 
beans, and after exposing the broth to the air until cool, cover and set aside for 
two or three days. Species of Spirillum may be obtained from sewer watr, or 
by letting water plants decay in a jar of water. Micrococci are common in the 
air, and may be obtained on boiled potatoes, gelatin, moist bread, etc., by letting 
these culture media remain exposed for a short time and then covering them to 
keep in the moisture. The bacteria will soon begin to appear in yellow, pink, 
purple, or red patches. 

1. Mount some of the hay infusion and examine under high power. Notice 
the minute free-swimming hay Bacteria, and draw several individuals. Draw 
several still hanging together in a filament after division. Describe the shape, 
color, and movement. Distinguish between the true locomotion of the Bacillus and 
the Brownian movement of the foreign particles present in the mount. 

2. Draw two individuals with spores. The movement is produced by means 
of flagella or cilia. 

3. Mount some of the bean broth and notice the putrid odor. Study the 
Bacillus present. Estimate the number of bacteria present in the field of the 
microscope. Counting the number across the diameter of the field and squaring 
will give approximate results. 

4. Suppose you had one bacterium to begin with, and that it and its descend- 
ants divided once every hour how many bacteria would there be at the end of each 
hour for 48 hours? 

5. Mount some material containing Micrococcus. Draw several individuals 
and describe. 

6. Mount and study some bacteria in the zooglcea stage (bacteria in gela- 
tinous masses.) Draw and describe. 

7. Mount some water containing Spirillum. Study the peculiar movement. 
Draw several individuals and describe. Represent the cell as a real spiral and 
not simply as a wavy line. 

8. Root-tubercle Bacteria. Collect fresh roots of white clover (Trifolium 
rep ens L.) or alfalfa (Medicago sativa L.). Sketch a rootlet showing numerous 
tubercles under dissecting microscope. Crush a large and a small tubercle on 
the slide, mount in water, and study the bacteria present. Draw a number of 
individuals, showing the following forms : irregular rods, club-shaped, T-shaped, 
Y-shaped, and X-shaped. Treat with iodin solution and note the color reaction 
of the starch and of the bacteria. This symbiosis is a case of mutualism. 

9. Mount some hay Bacilli and some Paramcecia tagether, and compare them 
as to size. The Bacillus and the Paramcecium are both single cells. About how 
much greater in volume is the Paramcecium than the Bacillus? In order to get 
fairly accurate results, find how many times wider, thicker, and longer the one is 
than the other. This can be done by projecting the organisms onto the table and 
measuring them with a millimeter rule. How near would the comparison hold 
with that of a mouse and an elephant? 


10. Note — To obtain Paramoecia, let a mass of Spirogyra or other water 
plants decay in a jar of water exposed to the air. The Paracecium is one of the 
most highly developed and specialized animals belonging to the Protozoa. 

IX. Slime Molds. Phylum, Myxophyta. Class, Myxomycetae. Order, 


The Myxomycetes are a group of organisms which approach very near to the 
animal kingdom, forming one of the several transition groups from the lower 
plants to the lower animals. They have developed a very complex life history, 
altho they are very simple plants. They usually grow on decaying logs and 
stumps, and may be collected in summer and autumn and kept in the encysted or 
resting stage for an indefinite length of time, and studied when conveniet. 

(a) Lycogala epidendrum (Buxb.). Family, Lycogalaceae. 

1. Make a sketch showing the naked eye characters of individuals in the 
resting stage (sethalia), and how they are situated on the wood. Describe. 

2. Moisten some of the downy material (capillitium) and a piece of the 
outer enveloping layer (peridium) in alcohol, and mount in water. Examine 
under high power. Is there any cell structure in the capillitium or peridium? 
Draw a part of the capillitium, showing the peculiar markings. 

3. Draw a few of the individuals (scattered thru the capillitium) in the rest- 
ing stage (spores), and describe. 

(b) Hemitrichia clavata (Pers.). Family, Trichiaceae. 

1. Mount one of the sporangia and sketch under low power, showing the 
stalk of the sporangium, the broken peridium, and the mass of capillitium threads. 
Describe shape, color, etc. 

2. Under high power draw some of the capillitium threads, showing all 
details carefully. 

3. Draw some of the individuals in the spore stage. 

(c) Stemonitis fusca (Roth.). Family, Stemonitacese. 

1. Mount and draw one of the plume-like sporangia under the dissenting 
microscope, showing the hypothallus, stalk, columella, and capillitium. 

2. Under high power, draw part of the capillitium, showing how it is attached 
to the columella. 

3. Draw some of the spores. 

(d) Plasmodium. 

' 1. Examine under the dissecting microscope, and describe the Plasmodium 
or a myxomycete in the moist living condition. This can usually be found on 
decaying logs during the spring, summer, and autumn. If living material is not 
at hand, examine pieces of Plasmodium preserved in alcohol. 

2. The flagellate stage of many species of myxomycetes may be obtained by 
simply making hanging drop cultures with water, or water in which decaying 
wood has been soaking. Fresh spores of Lycogala will germinate in a day or two, 
and the preparation can be examined from time to time under the high power. 


(c) Amoeba sp. Protozoa. Class, Rhizopoda. Order, Amoebida. Fam- 
ily, Amoebidae. 

If the student has not studied the Amoeba in a general course in zoology, it 
should be taken up at this point, since the amoeboid form probably represents one of 
the most primitive type of cells with which we have to deal. Amoebas can gen- 
erally be found in the ooze at the bottom of ponds and creeks. To obtain Amoebas 
in large quantities, pack a glass jar rather tightly with Ceratophyllum or with 
pond lily leaves, and cover with water. The dish should be covered up. After 
a week or two, when the plants begin to decay, Amoebas will usually be abundant. 

1. Scrape off some of the sediment from the Ceratophyllum leaves and mount 
in water together with some of the brown scum present at this time in the jar. 
Under high power search for transparent, naked cells of irregular shape, which 
.are slowly changing in outline by thrusting out pseudopedia. Sketch the outline 
of an individual six times successively, at intervals of ten seconds. 

2. Describe the amoeboid movement of the animal, and the formation of the 

3. Make a careful diagrammatic drawing of a large Amoeba, showing the 
outer limiting layer (ectoplasm), the inner more fluid granular part (endoplasm), 
the nucleus (if distinguishable), the contractile vacuole, and the various ingested 
foreign bodies, as diatoms, desmids, etc. 

4. Note. — Tn the form following, a return will be made to a typical plant 
related to Pleurococcus. 

X. Scenedesmus quadricauda (Turp.). Phylum, Gonidiophyta. Class, 

Pleurococcese. Order, Pleurococcales. Family, Scenedesmaceae. 

Scenedesmus is very widely distributed, and may be found in the sediment 
in the bottom of ponds, creeks, etc., along with diatoms and other microscopic 
plants at any season. It usually consist of a colony of four, more or less spindle- 
shaped, green cells. The two outer cells have four slender, pointed, prong-like 
projections extending diagonally outward, one at each corner of the colony. 

1. Mount some of the sediment containing Scenedesmus, and examine under 
liigh power. Draw and describe. 

2. Compare a number of colonies as to size, shape of cells, and appearance of 
the projections. 

3. In the sediment with Scenedesmus a simpler and much smaller green laga, 
Ankistrodesmus falcatus (Corda), belonging to the same family will probably be 
present. This consists of very slender, bent or doubly curved cells either separate 
or in masses. If present draw and describe. 

4. Note. — The thallophytes following are more highly developed forms and 
possess some type of sexuality or are forms supposed to be descendants from 
ancestors having a sexual process. They may be called the sub-knigdom Nema- 



XI. Diatoms. Phylum, Zygophyta. Class, Diatomese. Order, Diatomales. 

This order contains a large number of genera and species both living and 
fossil. Diatoms can always be found forming brown scums or sediments on the 
bottom of ponds, creeks, ditches, etc. 


1. Mount some sediment or water containing diatoms and study the different 
species present. 

2. Under high power, draw six different species, representing them from two 
to four inches long. They are unicellular plants with .two cilicified valves or 
shells which fit together like the lids of a pill-box. Represent carefully the mark- 
ings on the shell. In some species the ends and central portion of the valves are 
marked by nodules and these points are connected by a rib or suture called the 
raphe. These can be seen from the valve view. 

3. Notice the greenish, yellow or brown chromatophores, the nucleus, and 
the cytoplasm. How are the cell organs arranged? 

4. Look for chains or filaments of diatoms; also for stalked forms. 

5. Study dividing forms. Some species conjugate. Look for such forms. 

6. Study the movement. Does it have any relation to the field of the micro- 
scope, or the intensity of the light in the field? Describe. What is the cause of 
the motion? Remember that the motion is magnified under the microscope. How 
long does it take a diatom to pass across the diameter of the field? 

7. Isthmia sp. Scrape specimens of Isthmia from dry, red or brown algse or 
study from mounted slides. Isthmia can usually be obtained from dry algae' 
collected on the California coast. Draw a specimen from the girdle view, show- 
ing the valves and details of the markings. Notice that the individuals are of very 
different sizes. Draw one showing the valve view. Draw an individual in process, 
of division. Describe how the valves fit together, how new valves are formed,, 
and what is the character of the valves of the two individuals resulting from a 
division. Explain the cause of the difference in size. 

8. Fossil diatoms. Study material from the Tertiary deposit of Richmond,. 
Va. Place a fragment of the diatomaceous earth in a small bottle of HC1, crush 
gently and mount in water, or use prepared mounts. Draw three different species. 

9. Note. — Diatoms, on account of the great number of forms, make a good 
study in variation. There is a great variety of patterns without very much advance 
in structure or life cycle — horizontal evolution. Is there any special advantage 
in the great variety of fantastic markings on the valves? 

XII. Closterium sp. Phylum, Zygophyta. Class, Conjugate. Order, 
Desmidiales. Family, Desmidiacese. 

Desmids are quite common in ponds and lakes and species of Closterium can 
usually be found in the sediments at the bottom, on submerged water plants, or 
in large masses floating on the surface. Sometimes Closterium is very abundant in 
watering tanks, forming large, green, floating flakes. 

1. Mount in water and observe the large bright green, unicellular plants 
which are more or less curved or crescent-shaped. 

2. Draw an individual under high power, showing the cell wall with trans- 
vrese striations in the central region, the two large chromatophores (chloroplasts) 
with highly refractive bodies (pyrenoids), the large nucleus with nucleolus in the 
central, clear space, and the peculiar vacuoles at each end. Notice the dancing, 
crystaline granules of calcium sulfate in the vacuoles. (Brownian movement). 
Descibe in detail, noting especially the symmetrical halves of the cell. 

3. Notice the streaming of the cytoplasm between the large chloroplast and' 
the cell wall. Trace the current around the end of the cell. 

4. Look for dividing specimens. Draw and describe. 

5. Search for conjugating individuals and for zygospores. 


XII. Spirogyra sp. Phylum, Zygophyta. Class, Conjugatae. Order, 
Zygnemales. Family, Spirogyraceae. 

Spirogyra grows in stagnant water or slowly flowing streams, forming floccu- 
lent, floating masses of a bright green color which are slimy to the touch. It may 
be collected at any time but more commonly it conjugates in late summer and 
autumn. Some of the species will conjugate if brought into the laboratory and 
placed in an open dish of pure water. Metal is very injurious to Spirogyra. 

1. Study naked eye characters, noting that the mass is made up of slender 
free threads or filaments. 

2. Mount a few filaments in water and examine under low power. Notice 
the cells with spiral chromatophores (chloroplasts.) Shape of the filaments and 
cells? Count the number of cells across the' cover-glass (f inch across). How 
many? Measure a long filament and estimate the number of cells it contains. 

3. Draw part of a filament under low power showing ends, cells, and chro- 
matophores. Any difference between the two ends? Describe. 

4. Under a high power, draw a cell showing the wall with mucilaginous 
sheath, spiral chloroplasts, pyrenoids, nucleus, and nucleolus. How is the nucleus 
connected with the other parts? 

5. Draw part of a chloroplast showing details of the margin and the pyre- 

6. Treat with salt solution. Draw and describe what takes place. 

7. Study the conjugation from fresh material, or if this is not at hand, from 
material preserved in copper salt solution or from mounted slides. Notice two 
filaments side by side and that all the zygospores are in the cells of one filament, 
while the cells of the other filament are empty. This indicates a slight differ- 
entiation of sex individuals. Draw a piece under low power, showing a number 
of conjugated cells. 

8. Draw two conjugated cells showing all details carefully, especially the 
zygospore or zygote and the conjugation tube. 

9. Draw two cells in which the contents of one cell are passing thru the tube. 

10. Draw two cells in which the two 
rounded processes from the side hdve just etc. — 

11. Draw two cells in which the two 
processes are just beginning to develop. 

12. Describe fully the process of conju- 
gation as observed above. 

13. Look for cases of parthenogenesis ; 
either with a spore in one cell and a distorted 
protoplast in the other, or with a spore in 
each of the conjugated cells. 

14. Make a diagram in the notes show- 
ing the life cycle by means of diagram- Fig. 3. _ Diagram of Ancestry. 
matic figures of the plant, cells and spores. 

15. Make a diagram showing the ancestors of one spore for five generations; 
take no account of vegetative propagation or of the possible close relationship 
of conjugating individuals (see Fig. 3). Compare with Pleurococcus. How many 
ancestors have you yourself had in twenty generations or about 600 years? 



XIV. Sphaerella pluvialis (Flotw.). (Hsematococcus). Phylum, 
Gonidiophyta. Class, Protococceae Order, Volvocales. Family, Chlamydomona- 

Sphaerella may be found growing in rain water, drain tiles, roof gutters,, 
pools, or ponds. It is unicellular and green in color or sometimes a bright red. 
If a culture is once obtained, it may be preserved on a limestone rock or in a 
glazed earthen jar. Put the rock into the water containing the alga and after 
some time take it out and lay it away. Whenever material for study is required 
the rock need only be placed in fresh rain water, when a new crop will soon 

1. With a medicine dropper mount some water containing Sphaerella and 
examine under low power. Under high power study the large, green or red 
spherical cells in the resting condition. Draw. Notice the green and red coloring 
matters — chlorophyll and haematochrome. 

2. Draw an individual divided into two, and one divided into four or eight 
cells. How does the division take place as regards the cell wall. Compare with 

O — & 

Fig. 4. — Life Cycle of Sphaerella. 

Pleurococcus. Look for an individual in which the four cells are ready to break 
thru the old cell wall. The four cells form four free-swimming Sphaerellas which 
have very loose cell walls. 

3. Study the active individuals. Describe the shape, color cell contents 
(especially the chloroplasts and pyrenoids), and the flagella. The flagella branch 
out from a clear body in the pointed end of the cell and pass out thru two ex- 
tremely minute openings in the cellulose wall. 

4. Study and describe the movement. Which end is directed forward in 
swimming? How long does it take an individual to pass across the diameter of 
the field? Suppose the diameter is three-tenthes of a millimeter, how long would 
it take the plant to travel thirty centimeters or one foot? Is the motion rapid or 
slow? How many times its own diameter does an individual move in one second? 

5. The flagella and other parts may be seen more clearly by adding a small 
drop of iodin solution to the water at the edge of the cover-glass. What hap- 
pens? How long are the flagella, compared with the size of the body? Look 
for the nucleus. Notice the protoplasmic strands which pass from the cell-body 
to the wall. 

6. Notice the division of labor in the organism and designate the function 
of the following organs: a, cell wall; b } flagella; c, chloroplasts. 


7. Make a diagram in the notes showing the life cycle of Sphaerella when 
reproduction takes place by the formation of non-sexual zoospores. (See Fig. 4a.) 

8. Sexual stage. Look for individuals divided into eight or more cells. 
Draw. When these escape they are smaller than the four and at first have no 
cell walls. These zoospores are said to conjugate and form zoozygospores. Care- 
ful observations should be made in order to discover such a process. In case 
conjugation takes place the life cycle during this stage may be represented as in 
Fig. 4b. 

XV. Pandorina morum (Muell.). Order, Volvocales. Family, Volvocacese. 
Pandorina occurs in small pools of water, and is often very abundant in 

summer, coloring such pools a bright green. The individuals consist of a free- 
swimming colony of sixteen cells, and are more or less globular or oval in outline. 

1. Mount some of the colonies in water and examine under low power. 
Notice the active movement. Draw a colony under high power. If they cannot 
be followed because of their active movements, add a drop of carbolic aicid 

2. Notice the details of an individual cell of the colony; the two flagella, 
the red eyespot, the transparent spot in the outer end of the cell, and the chlor- 
oplast with a pyrenoid. 

3. Study and draw colonies in stages of division. Each of the sixteen cells, 
divides until each forms a group of sixteen new cells, then the gelatinous envelope 
dissolves and the sixteen daughter colonies are set free. This is the normal 
method of vegetative propagation. 

4. Sexual reproduction. > Look for colonies in which the cells are separating 
as isolated zoospores. These are the gametes which are very much alike, but are 
of various sizes. 

5. Watch for conjugating forms. Conjugation takes place between two 
gametes of equal size, or between a larger and a smaller one. The process is 
complete in a few minutes. Draw stages observed, and also mature zygospores. 
The difference in size of the conjugating gametes is of special importance, since 
it is the first step in the evolution of two specialized gametes, the oosphere and 

6. Note. — Pandorina is well preserved in water with carbolic acid, and 
large quantities may be collected at the proper season showing the various stages 
of the life cycle. Cultures can also be obtained in the laboratory from dry 

XVI. Eudorina elegans, Ehrb. Family, Volvocaceae. 

Eudorina frequently occurs in summer in pools of rain water, in ponds, and 
in marshes. The colonies are hollow, free-swimming bodies, more or less spheri- 
cal in shape, usually consisting of thirty-two cells which are considerably sepa- 
rated from each other. 

1. Mount a drop of water containing the organism and examine under low 
power. Under a high power draw a single colony, showing the arrangement of 
the cells. 

2. Draw a single cell, showing the two flagella, the red eyespot, and the 
chloroplast with a pyrenoid. 

3. Vegetative propagation. The individual cells divide into sixteen or thirty- 
two new cells, and these escape as daughter colonies the same as in Pandorina. 
Draw a colony showing daughter colonies, and describe. 


4. Sexual reproduction. The colonies are either unisexual or hermaphrodite. 
Draw a colony showing antherida (spermaries), consisting when mature of plates 
of sixty-four small cells each, which develop into male gametes (spermatozoids). 
Draw and describe free-swimming spermatozoids. 

5. Draw a colony containing female gametes (oosperes). The colony with 
oospheres differs very little from the ordinary vegetative colony. Watch for 
spermatozoids swarming about the female colonies. 

6. Draw and describe the ripe, red-colored oospore. 

7. Note. — Eudorina shows a considerable advance in sexual development 
over Pandorina. The female gamete (oosphere) has become stationary, but still 
retains its flagella at first, and does not divide. The male gametes (spermatozoids) 
are formed by the repeated division of the cells of the colony. They are very 
small in comparison with the female cell, swim about freely in the water, and 
have lost their chlorophyll. 

XVII. Vclvox globator L. Family, Volvocaceae. 

This alga is of such size that its spherical, free-swimming body can easily be 
seen with the naked eye. In summer and autumn it can frequently be found in 
fresh water ponds and lakes. 

1. Take up some of the spherical colonies with a large-mouthed medicine 
dropper or a glass tube and, having formed a little chamber on the slide with 
a xylonite ring or with paraffin, mount and study under low power. Note the 
rotating movements of the hollow, spherical organism. 

2. Draw a colony showing the numerous cells and some daughter colonies, 
which appear as darker green spherical masses of various sizes. 

3. Under high power, study a single colony. About how many cells in a 
colony of average size? Draw a few cells, showing the cell walls, the proto- 
plasmic strands, connecting the cells (protoplasmic continuity), the chloroplast, 
the red eyespot, the pulsating vacuole, and the two flagella of each cell. The 
flagella will be more distinct after staining with iodin. 

4. Describe the devleopment of a daughter colony from one of the cells of 
the mother colony. Look for an opening (the pore) in one side of the young 
colonies. What advantages may there be in the hollow spherical form? 

5. Sexual reproduction. The colonies are hermaphrodite, developing both 
sexual organs — the ovaries or oogonia and the spermaries or antheridia — in 
late summer or autumn. Draw an antheridium. This represents an enlarged cell 
of the colony which has divided into a large number of elongated cells arranged 
like a bundle of asparagus shoots. 

6. Draw an oogonium, projecting into the cavity of the colony, showing the 
enlarged oosphere. Draw a ripe oospore, showing the thick wall with peculiar 
angular points on the surface. 

7. Note. — In Volyox complete sexuality has been attained with the normal 
conditions of the sexual cells (gametes). It will be noticed that the plant is 
hermaphrodite, and this is the more usual condition in the lower plants. 

XVIII. Vaucheria sessilis Vauch. Phylum, Gonidiophyta. Class, 
Siphoneae. Order, Vaucheriales.. Family, Vaucheriaceae. 

This alga grows as a lax, green, felt-like layer on the surface of moist soil, 
and is especially common on the surface of pots in greenhouses, and may here 
be in fruit at any time of the year. Other species may be found in ponds. 


1. Describe the naked eye characters, noting the coarse cylindrical filaments. 

2. Under low power draw an entire filament showing the branches, the tips, 
and the clear or decaying part of the back end. Note the absence of transverse 
walls. Such a plant body is called a cenocyte. The protoplasts are not separated 
by walls. How does the filament grow? 

3. Under high power draw a short piece of a young filament, showing details- 
— shape, vacuole, arrangement of protoplasm, chloroplasts, and oil drops. Posi- 
tion of chloroplasts? How can you tell that the filament is cylindrical without- 
seeing a cross section? 

4. Draw several chloroplasts. Shape? Draw some in stages of division. 
Describe. Look for movement of the protoplasm. 'Numerous nuclei are present 
in the cytoplasm, but these are not visible without special staining. 

5. Study the sexual organs, the antheridium (spermary), and oogonium 
(ovary). They are usually side by side. Draw carefully and describe. Notice- 
the septa which separate the sexual organs from the main filament. Vaucheria 
is hermaphrodite, having male and female organs on the same individual. 

6. Draw the oosphere (unfertilized egg) ; also some spermatozoids in the 
autheridium. Look for free-swimming or escaping spermatozoids ; also for sper- 
matozoids entering the oogonium. 

7. From the union of the two gametes an oospore or zygote is formed. 
Draw a ripe oospore showing the thick wall and more or less hyaline contents. 
Describe. Note that fertilization, in this case, is not the stimulus for further 
development but is followed by a resting stage. 

8. Contrast the two sex cells (gametes) as to size, motion, and nutrition. 
How is an oospore different from a zygospore? Would there be any advantage 
in this? 

9. Special vegetative propagation by means of volvox-like colonies (com- 
pound zoospores), produced in the ends of the filaments, may be obtained as fol- 
lows: Place a mass of Vaucheria in a porcelain dish, in water, and expose for a 
few days in the window until small Vaucheria plants are found floating on the 
surface. Examine very early in the morning and the volvox-like colonies may be- 
seen escaping from the swollen ends of the filaments. In order to observe the 
colonies later in the morning, cover the dish, the evening before observation is to^ 
be made, so that the plants will be in absolute darkness until shortly before the 
material is to be studied. Study and draw. Describe in detail the formation of 
the compound zoospores and how they develop into new Vaucheria plants. Might: 
this process indicate some relation of the ancestors of the Vaucheria to the Vol- 

10. Make a diagram in the notes, showing the life cycle of Vaucheria. (See 
Fig. 5.) 

11. In the notes, make diagrams of the two gametes of Sphaerella, Pan- 
dorina, Eudorina, and Volvox, and describe how these may indicate stages in the- 
evolution of perfectly developed oospheres and spermatozoids. 

12. Note. — The oosphere and spermatozoid are highly specialized cells, the 
first representing nutritive qualities, the second the active qualities. A union of 
the two must result in a very perfect reproductive cell. The development of sexual 
individuals appears to be along the same lines as indicated in the sexual cells. 
Maleness or femaleness is not an hereditary character or factor, but a condition 
and often depends on the environment present during the germination of the spore- 
or the development of the embryo. In some of the intermediate plants the sexual' 
development can be controlled while in the higher groups the sex of the gametophyte- 
is always determined in the spore. 




XIX. Pediastrum pertusum Kuetz. Phylum, Gonidiophyta. Class, 
Hydrodictyese. Order, Hydrodictyales. Family, Hydrodictyaceae. 

This beautiful alga is found along with other species of the same genus in 
the sediments at the bottom of ponds and creeks, and is especially abundant in 
the plankton of fresh water lakes and bays in summer and autum. It is a flat 
colony of cells which develop into cenocytes. 

1. Mount some of the sediment containing Pediastrum in water and study 
under high power. Draw two of the plate-shaped colonies — one with sixteen 
cenocytes and one with thirty-two or more. Notice the difference between the 
marginal cenocytes and those in the interior. Note also the chloroplast and one 
or more pyrenoids. 

2. Look for colonies in which the cells in each cenocyte have separated, 
preparatory to the formation of a new colony. 

3. Draw a colony in which some of the cenocytes are empty, each empty 
shell having a slit-like opening thru which the daughter colony escaped. 

Fig. 5. — Life Cycle of Vaucheria. 

XX. Hydrodictyon reticulatum (L.). Water-net. Family, Hydrodictyaceae. 

The water-net forms a large body, which is common in summer and autumn 
in ponds and canals. It may often be collected in great quantities along the 
grassy banks of ponds in city parks. The body of the alga is made up of a very 
great colony of cylindrical cenocytes arranged in the form of a sack-like net. 

1. Examine a large plant and describe the naked-eye characters. If fresh 
material is at hand, place the plant for some time in direct sunlight and note the 
bubbles of gas collecting in the nets. Of what use? What is the gas. 

2. Draw a small portion of a young net under low power, showing how the 
meshes are formed by the joining of a number of cenocytes. Describe. 

3. Under high power draw a single cenocyte, showing the chloroplast and 
numerous pyrenoids. 

4. Vegetative propagation. Study and draw a large cenocyte of an old net 
in which the cells are developing a daughter net. 



XXI. (a) Caulerpa crassifolia (Ag.). Phylum, Gonidiophyta. Class, 
Siphonese. Order, Caulerpales. Family, Caulerpaceae. 

This is a large, much branched, cenocytic plant which reproduces by the 
branching of the thallus. The creeping, rhizome-like portion 'develops leaf-like, 
lobed branches, and continues to grow in front while it dies behind. It grows, 
within the tropics on sandy ocean shores at a depth of several meters. Preserved 
material will be necessary. 

1. Sketch the entire plant showing the creeping "rhizome," the leaf-like 
lobed branches, and the branching root-like hold-fasts. 

2. Mount part of a leaf-like branch and examine under low and high power. 
Note that there are no septa or walls in the plant body. Note the chloroplasts. 

3. Examine a cross section of the cylindrical "rhizome" under low and high 
power. Note the numerous branched and anastomosing cellulose braces stretched 
across the cavity. Draw. 

4. Note. — Caulerpa represents a plant which has developed the extreme 
type of a cenocytic body. The body takes on a shape suitable to its activities, by 
its branching habit affording sufficient surface for absorption and photosynthesis. 
The rigidity of the body is secured thru the complicated system of braces rather 
than by cell walls. Compare Note 6 on Pleurococcus. 

(b) Botrydium granulatum (L.). Phylum, Gonidiophyta. Class, Siphoneae. 
Order, Botrydiales. Family, Botrydiaceae. 

This alga is common in summer and autumn, especially after heavy rains, 
on wet ground in fiields and around ponds, where it forms little green pearshaped 
bodies with rhizoids extending into the soil. 

1. Draw a thallus under dissecting microscope or low power, showing the 
pear-shaped serial part and the branching rhizoids. Describe, noting the division 
of labor in the plant body and that it is a cenocyte. 

2. If material is at hand study some plants which are producing zoospores. 
Examine under high power and describe. How many flagella? 

XXII. Cladophora sp. Class, Siphoneae.. Order, Cladophorales. Family, 

Species of Cladophora are commonly found in flowing water. They appear 
as large, dark green extensively branched tufts, attached to rocks and pieces of 
wood. These algae are also abundant along the shores of lakes, where they may 
often be found attached to objects which are exposed to the action of waves. 
They may be obtained at any season. 

1. Describe the naked eye characters ; size, mode of growth, color, habitat, 
etc. Note the differentiation of base and apex. 

2. Mount a small branch of the thallus in water and study under low power. 

3. Under high power study the stages showing the development of a branch, 
Make four drawings showing four general stages: (1) a small bulging out of 
the cell wall on one side below the septum; (2) a short branch with the proto- 
plasm still connected with the parent cenocyte; (3) the branch cut off from the 
parent cenocyte by a septum; (4) a branch divided by a transverse septum into 
two cenocytes. 


4. Draw a single cenocyte or division between two cross walls, showing the 
irregular chloroplasts and the pyrenoids. Notice the large central vacuole. Apply 
salt solution and note the effect. Numerous nuclei are present, but these can 
probably not be distinguished from the pyrenoids without special staining. Stain 
with iodin solution and draw. It is a cenocytic plant with numerous transverse 
walls, but the wall do not represent cell divisions. How and where do the 
branches always originate? 

5. Draw and describe an empty cenocyte or zoosporangium from which 
zoospores have escaped. Where is the opening (ostiole) always formed? 

6. At certain times zoospores may be seen forming and escaping into the 
water. This frequently occurs in material which has been kept in water in a warm 
room. Draw a cenocyte in which the zoospores are developing. 

7. Draw a cenocyte in which the zoospores are fully formed. Look for 
.zoospores in the act of escaping thru the ostiole. 

8. Study and draw free-swimming zoospores, showing the chloroplast and 
red eyespot. To make the two flagella visible treat with iodin solution by placing 
a drop on the slide beside the cover-glass and letting it mix slowly with the 
water of the mount. 

9. Draw a zoospore which has begun to develop into a new filament. The 
•embryo developing from a free spore is called a sporeling. 

10. The zoospores (planogametes) of some species are said to conjugate. 
Look for such a process. 

XXIII. Ulothrix zonata (W. & M..). Phylum, Gonidiophyta. Class, 
Conferveae. Order, Confervales. Family, Ulothrichacese. 

This Ulothrix is a small, unbranched, filamentous, green alga which usually 
.grows in running water, attached to sticks and stones. It may be found in slow- 
flowing streams, in watering troughs, or in fountains. Collect the material and 
place it in a shallow dish in about two inches of water, and in a day or two, after 
the water has evaporated somewhat, large non-sexual zoospores and sexual gametes 
will probably be forming. Study the fresh material and preserve some for further 

1. Mount some of the filaments containing the basal cells (hold fasts) and 
study under low power. Draw. 

2. Under high power draw the holdfast, the terminal cell, and two or three 
of the central cells; showing the wall, the chloroplast, and the nucleus. Describe 
these parts. 

3. Non-sexual zoospores. Examine a filament in which the cells are form- 
ing either one, two, or four zoospores each. Observe how they escape by a lateral 
opening in the cell-wall. Draw and describe. These spores have four flagella 
and a pulsating vacuole. Draw an empty cell. 

4. Sexual reproduction. Study a filament in which the cells have developed 
a large number (eight, sixteen, or thirty-two) small gametes of equal size (iso- 
.gametes). Draw part of the filament showing some cells empty and some with 
gametes. The gametes have only two flagella. 

5. Observe the conjugation of the planogametes to form zoozygospores. Draw 
and describe. In order to bring out the flagella more clearly, stain with iodin 
.solution. If the gametes do not conjugate some may round themselves off and 
become resting spores. This is a case of parthenogenesis. 

6. Note. — When the zygospore germinates it does not develop a new fila- 
mentous plant, but gives rise to a number of cells which develop as non-sexual 


zoospores, and these escape and produce the filamentous plant. Ulothrix, there- 
fore, along with many other thallophytes, has what is known as an alternation of 

XXIV. Ectocarpus confervdides (Roth.). Phylum, Phaeophyta. Class, 
Phaeosporese. Order, Ectocarpales. Family, Ectocarpaceae. 

This alga has a branching filamentous frond and grows in summer attached 
to other algae or to submerged objects along the seashore. 

1. Note the form of the plant and mode of attachment. Draw. 

2. Examine under low power. Are the cells in a single row? Draw a branch. 

3. Study and draw a plurilocular sporangium ; also draw one of the unilo- 
cular sporangia which are usually developed somewhat earlier than the plurilocular 
ones. The unilocular sporangia produce non-sexual zoospores and the plurilo- 
cular sporangia produce planogametes. 

XXV. Fucus evanescens Ag. Phylum, Phaeophyta. Class, Cyclosporeae. 
Order, Fucales. Family, Fucaceae. 

This brown alga is common along the Atlantic coast. It may be obtained 
from dealers in botanical supplies, and preserved in alcohol or other solutions, 
or they may be dried and soaked in water when needed. Various species of Fucus 
may be found fresh at fish stores in large cities, these plants often being used as 
packing. The thallus is a large, flat, dishotomously branching frond of a dark 
brown color, attached to various objects by means of a disk-like holdfast. 

1. Place the plant in a plate of water and draw the large thallus. Describe. 
Note the holdfast, the flattened dichotomous frond, and the thicker central region 
forming a sort of midrib. Xote also the swollen tips of the branches (receptacles), 
covered with numerous dot-like projections. 

2. Find the growing points of the thallus in branches which do not have 
receptacles. Note the emarginate apices which have a slight groove lying in the 
plane of the thallus. Draw under low power. The initial cells are at the bottom 
of this groove. How are the branches formed? 

3. Cut thin cross sections of a branch of the thallus with a razor, mount, 
and examine under low power. Draw. Note the outer, denser, cortical layer, and 
the loose, inner region, with elongated branched filaments and much mucilage. 

4. Cut thin cross sections of a receptacle, mount, and examine under low 
power. Note the conceptacles, cavities opening by means of ostioles on the ex- 
terior. Sketch the entire section. 

5. Select a favorable conceptacle and draw showing the ostiole, the wall of 
the conceptacle, the sterile hairs, the large, dark-colored ovaries (oogonia) of oval 
form, and the small yellowish spermaries (antheridia) situated on branched hairs. 

6. Under high power draw and describe a single antheridium showing cells- 
developing into sperma'tozoids. About how many sperms does an antheridium 

7. Draw and describe an oogonium containing the eight ripe oospheres. 

8. Compare the egg and sperm cells. About how much larger in volume is 
one than the other? 

9. If fresh material can be obtained, study the spermatozoids and oospheres 
after their escape from the sexual organs. Take a plant with mature receptacles 
from sea water and expose it to the air for several hours. Mount some of the 
exudation, which appears at the ostioles of the conceptacles, in sea water, and 


examine under high power. Notice the large spherical oospheres and the small 
motile spermatozoids. Study the process of fertilization, and describe. Draw an 
oosphere surrounded by spermatozoids. The discharge of, the egg from the ovary 
into the water is a very unusual phenomenon in the plant kingdom. Compare 
with Vaucheria and Volvex. 


XXVI. Mucor stolonifer Ehrenb. Black Bread Mold (Rhizopus 

Phylum, Mycophyta. Class, Zygomycete. Order, Mucorales. Family, Mu- 

This fungus can nearly always be obtained by placing a piece of old bread for 
several days in a moist chamber. An ordinary glass or jar with a cover will do 
very well for making the culture. Enough water should be added to keep the 
bread moist without soaking it. The fungus forms a white flocculent mass of 
cottony filaments (the mycelium made up of hyphae) over the surface of the 
bread and later also spreads out over the walls of the glass. Some of the hyphae 
will be seen to rise vertically into the air and end in rounded black heads. These 
are the sporangia containing the non-sexual spores. 

1. Describe the naked eye characters noted above. Notice habitat and color. 
Notice also (1) the hyphae passing down into the substance of the bread, (2) the 
horizontal stolen-like hyphae, and (3) the upright sporangiophores. 

2. Cut off a flake of the young hycelium with a pair of scissors and mount 
in water, taking great care not to injure the delicate hyphae. Study under low 
power and draw some of the hyphae showing mode of branching. 

3. Mount carefully and under high power draw part of a hypha and describe. 
Any transverse septa (cross walls) ? If not, what kind of a fungus is it? (Com- 
pare with Vaucheria.) How does this plant differ from the green algae in general? 
Difference in mode of obtaining food? Why is this plant called a saprophyte? 

4. Study and draw a cluster of sporangiophores showing the rhizoids at the 
base and the sporangia at the tips. The best are those taken from the walls of 
the dish. Color? Draw a single unbroken sporangium showing the columella on 
the inside, and the non-sexual spores. Do not mistake the columella of a broken 
sporangium for the entire body. Describe the structure of the sporangium. What 
does the columella represent? The sporangia burst readily because of the presence 
of an intermediate substance which swells readily in water. Of what use is this? 

5. Draw and describe the non-sexual spores. Color? About how many in a 

6. This plant has a partial development of sexuality, and under suitable con- 
ditions, if the female and male (or + and — ) strains are growing together, pro- 
duces zygospores. If any of these are at hand or material from another species, 
study and draw showing the following stages. 

a. Two neighboring branches of the mycelium, which are about to conjugate 
and which are in contact. 

b. The stage in which the two branches have fused. 

c The stage in which transverse septa are formed, cutting off the apical part 
of each conjugating branch. Any difference between the conjugating branches in 
size or contents? 


d. The absorption of the wall separating the conjugating tips and the subse- 
quent mixing of the two cenocytic protoplasmic masses. 

c. The mature zygospore suspended between the two branches. 

XXVII. Empusa muscae Cohn. Fly-cholera Fungus. 

Phylum, Mycophyta. Class, Zygomycete. Order, Entomophthorales. Family, 

This fungus grows on the common house fly (Musca domestica) . In the 
.autumn dead or dying flies attacked by this fungus may be seen with greatly 
swollen abdomens of a white color. Specimens may be preserved in alcohol. 

1. Study a fly recently killed by this fungus ; under low power without a 
cover-glass. Note the bands of short white hyphse (conidiophores) protruding 
from between the black segments of the abdomen. Draw and describe. 

2. Tear open the abdomen with needles and mount the white contents and 
some of the conidiphores in water. Examine under high power. Notice that the 
mycelium has nearly absorbed the contents of the fly's abdomen. 

3. Draw some of the conidiophores with conidia still attached; also draw 
several of the conidia. Describe. Is the fungus a parasite or a saprophyte? 

XXVIII. Saprolegnia sp. Water mold. 

Phylum, Mycophyta. Class, Oomycetse. Order, Saprolegniales. Family, Sap- 

This fungus can usually be obtained by placing dead flies in a dish of spring 
or pond water. After about five or six days the hyphae of the fungus may be 
seen protruding from the body of the fly. On the tips of these hyphse sporangia 
are developed which discharge numerous zoospores. 

1. Notice the fly in the water, surrounded by a halo produced by the mycelium 
of the fungus. 

2. Mount some of the mycelium in water and examine under low power. 
Draw a branch under high power, showing the granular protoplasm and a terminal 
sporangium developing zoospores. Draw a branch showing an empty sporangium. 

3. Study and draw free-swimming zoospores. Oospores may also be present. 

XXIX. Plasmopara viticola (B & C). Downy Mildew of Grape. 

Class, Oomycetae. Order, Peronosporales. Family, Peronosporacese. 

This mildew causes a destructive disease of the leaves and young shoots of 
the cultivated grape. The infected leaves may be collected in spring or summer 
and preserved in 70 per cent, alcohol or dried and kept in paper boxes. 

Conidial stage. 

1. Examine a leaf carefully under the low power, without cover-glass. On 
which side do the conidiophores appear? 

2. Carefully scrape off some of the conidiophores with a needle or scalpel, 
mount in water, and examine under low power. Under high power draw one of 
the much branched conidophores. If dry material is used the conidia will probably 
all have dropped off. One is developed at the tip of each peg-like branch of the 


3. Draw several conidia and describe shape, size, and color. 

4. From alcoholic material cut cross sections of a part of a leaf containing- 
the fungus, mount, and under low power note that the conidiophores come out in 
bunches thru the stomata of the leaf. Draw. 

5. To what physiological group does this fungus belong — parasite or sapro- 
phyte? Describe its mode of life so far as studied. 


XXX. Chara sp. 

Phylum, Charophyta Class, Chareae. Order, Charales. Family, Characeae.. 

The stoneworts are algae which are found growing in the bottom of ponds,, 
lakes, or slowly flowing creeks and rivers. They are of considerable size and are 
usually covered with an incrustation of lime. They contain numerous branches 
arranged in whorls and are firmly fixed in the mud by means of rhizoids. Charas 
grow very readily in an aquarium and may be kept in a healthy condition all 
winter by simply placing the plants into a glass jar of water and keeping them 
near a south window. 

1. Sketch an entire plant and describe the naked eye characters. Notice the 
odor, the nodes and internodes, and the brittleness of the filaments. 

2: Mount the base of a plant in water and examine under low power. Draw 
and describe some of the branching rhizoids. Study the rotation of the proto- 
plasm under high power. 

3. Mount the treminal part of a young branch, being careful so as not to 
crush the brittle lateral branches. Examine under low power and draw the 
terminal bud. Notice the great internodal cells covered with a cortical layer and 
the whorls of lateral branches. 

4. Draw a cell of one of the branches without a cortical layer, showing the 
incrustation of lime. 

5. Under high power draw a part of a cell, showing the chloroplasts. How 
are they arranged? Draw several in stages of division. How do they divide? 

6. Study the rotation of the cytoplasm in the large cells of the branches and 
describe. How does it differ from that in the cells of Philotria? Why are the 
chloroplasts arranged in rows? Note the movements in opposite directions on 
either side of the neutral line. Is the direction of rotation the same in all the 

7. How is the cortical layer developed? In order to determine this, young 
branches should be obsreved. Draw a cross section of the main stem. Note the 
short projecting cells which roughen the surface. 

8. The sexual organs are produced during summer and autumn. Study 
fresh material, or if this is not at hand, material preserved in alcohol or copper 
solution. The spermaries (antheridia) and ovaries (oogonia) are situated on the 
lateral branches. Draw. Notice the five spiral branches which cover the ovary. 
How does this ovary differ from that of Vaucheria? The spermaries are globular 
organs which are red in color when fresh. Is this plant hermaphrodite or uni- 
sexual? If the incrustation of lime is too thick remove it with Perenyi's fluid. 

9. Crush a ripe spermary under the cover-glass and draw one of the numer- 
ous filaments inside. The small cells of these filaments contain the spermatozoids. 
Draw a single cell showing a mature spermatozid. How many cells in a single 
filament? Suppose the spermary contains 8x6x4 filaments, how many spermao- 


zoids would there be produced in each spermary? How many spermatozoids for 
each oosphere or egg? 

10. Draw an ovary containing a ripe oospore. Explain the structure of the 
entire body. Crush the oospore and note the starch. Treat with iodin. 

11. Study the proembryo, from which the normal Chara plant develops as 
a lateral bud. Draw and describe. Proembryos may be obtained by placing plants 
with mature spores in a glass jar of water and keeping them over winter. In 
the spring the embryos will be found at the bottom. 

12. Make a diagram showing the life cycle of Chara. Compare with Vau- 

XXXI. Batrachospermum moniliforme Roth. 

Phylum, Rhodophyta. Class, Floridese. Order, Nemalionales. Family, Hel- 

Batrachospermum is an alga of considerable size which can be found attached 
to stones in fresh water rivulets and creeks. 

1. Spread out the frond of the alga in water in a porcelain plate and sketch 
the entire plant. 

2. Mount some of the branches in water, crushing them considerably under 
the cover-glass, and sketch under low power. 

3. Under high power draw one of the lateral branches coming out from the 
nodes. Xote the oval cells and the bristle-like projections on some of the terminal 

4. In a young, main branch study the branches which pass down from the 
base of the nodal branches and form a loose cortical layer. How does this com- 
pare with the cortical layer in Chara? 

5. Crush some of the older branches under the cover-glass by pressing and 
rubbing carefully over the surface with the handle of the needle and study the 
ovaries. These are situated on the lateral branches, and each consists of a thick- 
ened hair-like process (trichogyne) and a bulbous base (trichophore) containing 
the oosphere. Draw. 

6. Study the spermaries, which are single terminal cells, each of which de- 
velops a single spherical male gamete (spermatium) without flagella. Draw a 
spermary and a free floating spermatium. 

7. Draw an ovary which has one or more spermatia attached to the 

8. Draw a sporocarp under low power. This is a sperical cluster of branches 
which develops from the fertilized egg. 

9. Under high power draw a nonsexual carpospore at the end of one of the 
branches of the sporocarp. 

10. From the foregoing study it will appear that Batrachospermum possesses 
a sort of an alteration of generations. Besides this, it has another interesting 
stage. When the carpospore germinates it gives rise to a peculiar filamentous 
proembryo or protonema, formerly known as the chantransia stage, from which 
the normal Batrachospermum plant develops as a lateral bud. Protonemal plants 
should be collected showing various stages in the development of the Batrachos- 
permum bud. The protonemal (chantransia) filament can reproduce itself by 
means of non-sexual spores developed on the tips of its branches. This is a case 
of reproduction known as pedogenesis, since the process is accomplished while the 
plant is in the immature condition. If material is at hand, draw and describe the 
chantransia filaments and spores. 


XXXII. Polysiphonia variegata (C. Ag.). 

Phylum, Rhodophyta. Class, Floridese. Order, Ceramiales. Family, Rhodo- 

Polysiphonia grows in abundance on rocky sea coasts. The plants may be 
found in summer as purplish-brown tufts, a few inches long on other larger water- 
plants, or on piles and stones. Preserved material may be used by those living 
away from the seashore. 

1. Spread out a frond in a porcelain plate and sketch the entire thallus.. 
Note the holdfast, if present, and the mode of branching. 

2. Mount a branch and draw under low power. Note that the body of the 
thallus consist of successive tiers of cells, each tier consisting of a central cell,, 
surrounded by a layer of cortical cells. 

3. Under high power draw a single tier of cells. Crush the thallus a little 
and note especially the large protoplasmic strands (protoplasmic continuity) which 
run from the central cell to the several cortical cells of the tier. Note also, the 
strands connecting the cells of a tier with those of the tiers above and below. 

4. Cut cross sections of the thallus, mount, and study under high power. 
The sections may easily be obtained by chopping up a moist branch on a piece of 
paper with a sharp scalpel. Draw, showing the arrangement of the central and 
cortical cells and also the protoplasmic connections. 

5. Under high power study the tip of a young branch and draw. Notice the 
dome-shaped apical cell and a number of cells below. The lower ones are divided 
by longitudinal walls. How are the tiers and the cortical cells developed? From 
this it is evident that, altho Polysiphonia appears like a branched filament and 
continues to develop as such, it finally forms a true solid aggregate. 

6. Nonsexual spore reproduction. Mount branches of plants containing tetra- 
sporangia (dark spherical bodies below the cortical cells) and draw under high 
power. Draw the spore tetrad and one of the mature spores. 

7. Sexual reproduction. The spermaries (antheridia) are borne on delicate, 
colorless dichotomously branched filaments, which form tufts on the younger 
part of the frond; the ovaries (oogonia) are on short branches in the upper part, 
or the individuals may be unisexual. Mount branches containing spermaries and 
draw under high power. Note the slender tip of the branch which extends beyond 
the oblong spermary. Note also that the sexual plants have no tetraspores. 

8. Development of the ovary. Mount branches containing young ovaries and 
under high power draw: (a) a short lateral simple branch showing one of the 
cells considerably enlarged and more or less spherical; (b) one in which this 
cell has divided by vertical walls into four cells; (c) one in which the inner cell 
of the tier of four has enlarged and divided into three or four cells by transverse 
walls, the upper one developing into the ovary with a basal trichophore and a 
slender trichogyne ; (d) a young cystocarp showing the trichogyne protruding 
from the mass of cells forming the wall. 

9. Draw a mature cystocarp, showing the more or less ovate-globose wall and 
the carpostome. 

10. Crush one of the mature cystocarps and draw several of the dark colored, 
nonsexual carpospores. 

11. Note. — Polysiphonia has an alternation of generations, since the spores 
of the cystocarp and the tetrasporic plant are homologous to the sporophyte of 


higher plants. Note that the sporophyte is at first nursed by the gametophyte then 
produces a number of independent spores. Its life cycle may be stated as follows : 

f spermatium ) 
Sexual plant or gametophyte < oosn v, e re r fertilization — germination of oospore 

— carpospores — tetrasporic plant or sporophyte (nonsexual) — sporocyte — reduc- 
tion division — tetraspores — gametophyte, etc. 


XXXIII. Aspergillus herbaridrum (Wigg.). Common Green Mold. 
Phylum, Mycophyta. Class, Ascomycetse. Order, Aspergillales. Family, 


This mold is exceedingly common on improperly canned fruit, on cheese and 
on decaying plants ; especially on plants in press for the herbarium when the 
driers are not frequently changed. The conidial stage is of a greenish color while 
the ascosporic stage is of a bright yellow-orange to the naked eye. 

1. Conidial stage. Mount carefully in water and study under low power. 
Under high power draw a conidiophore with conidia. Describe. How are the 
conidia developed ? Draw a piece of the vegetative mycelium, showing the trans- 
verse septa. 

2. Ascus Stage. Mount some of the white mycelium around the margin of 
the yellow centre. Under high power draw some of the peculiar coiled hyphal 
bodies present. These represent the conjugating branchs, from which a fruiting 
body devolops. 

3. Draw the mature fruiting body (ascocarp) under high power, from a 
mount of the yellow colored mycelium. Notice the asci containing ascospores. 

4. Crush the ascocarps under the cover-glass and draw an ascus with spores. 
Describe the life history of the plant. The ascocarp may be compared in a general 
way with the cystocarp of Polysiphonia. 

XXXIV. Morchella esculenta (L.). Morel. 

Class, Ascomycetse. Order, Helvellales. Family, Helvellacese. 

This edible morel is common in spring and summer in moist woods and shady 
hillsides. Specimens may be preserved in 70 per cent, alcohol. 

7. Make a careful sketch of the entire, fleshy, fruiting body, representing 
the stalk and the deep-pitted pileus on whose surface the asci are borne. 

2. Tease out a piece of the stalk and mount in water. Examine under high 
power and draw some of the mycelial threads. Note that the entire body is a 
spurious tissue of interwoven septate hyphae. Compare with Mucor. 

3. Tease out a small piece of the pileus, mount, and study the asci. Draw. 
How many ascospores in an ascus? How do the asci open at the tips? 

XXXV. Uncinula salicis (DC). 

Class, Ascomyceta?. Order, Perisporiales. Family, Erysibacese. 

This powdery mildew grows as a parasite on the leaves of various species of 
willow and can usually be found without difficulty in the autumn. It forms a white 
layer on the surface of the leaf in which minute black bodies are situated. It may 
be preserved in 70 per cent, alcohol or kept in a paper box. 

1. Moisten a leaf with water and scrape off some of the mycelium con- 
taining the black bodies (cleistothecia). Mount in water and examine under low 



power. Under a high power draw a cleistothecium with appendages. Be careful 
to have one that is mature. 

2. Draw a single appendage. Of what use are the appendages and the coiled 
tips? Draw a small piece of the mycelium showing the transverse wall in the 

3. Crush some of the cleistothecia under the cover-glass by pressing and 
rubbing carefully over the surface with the handle of the needle. Draw an ascus 
containing ascospores. How many asci in a cleistothecium? How many spores 
in an ascus? 

XXXVI. Saccharomyces cerevisiae Meyen. Beer and Bread Yeast. 

Phylum, Mycophyta. Class, Ascomycetse. Order, Saccharomycetales. Family, 

To obtain yeast plants in active, vegetative condition, take a piece of ordinary 
dry yeast cake and put it in a glass of water containing a small amount of sugar. 
Keep over night in a warm place. 

1. Mount some of the water containing yeast plants and study under high 
power. Draw several of the large oval cells present; also a short, branched' fila- 
ment of cells. 

2. Notice the formation of new cells by process of budding. Draw a number 
of cells showing the several stages in the formation of a daughter cell. 

3. Compare the size of a yeast cell with one of the bacteria present. 

4. Stain with iodin solution. Notice, the yellowish-brown color of the yeast 
plants and the blue of the large starch grains of the yeast cake. Is there any 
starch in the yeast cells? ■ 

5. Draw a large cell carefully, showing granules in the protoplasm and one 
or more vacuoles. 

6. Note. Yeast plants produce alcoholic fermentation in saccharine solu- 
tions. Dry bread yeast is usually a form of the beer yeast, and is known as 
"surface yeast." 

XXXVII. Ustilago zeae (Beck.). Corn Smut. 

Phylum, Mycophyta. Class, Teliosporeae. Order, Ustilaginales. Family, 
Ustilaginacese. ■ 

The corn smut may be collected in summer and autumn and kept in a dry 
condition in paper boxes. 

1. Make a naked eye sketch of one of the large, black, smut nodules. On 
what parts do the smut nodules develop? 

2. Mount some of the black powder and study under high power. Draw a 
number of the small spores. These are usually known as chlamydospores, or 
teliospores. Describe the color, surface and shape. 

3. Make a hanging-drop culture of the spores with dilute, boiled, stable- 
manure water. Smut spores germinate quite readily, but it is best to let them 
freeze before making the culture. Watch the germination from day to day and 
note the formation of the small promycelium or basidium which develops a number 
of hyaline basidiospores. Note that the smut plant is a parasite while the pro- 
mycelium is a saprophyte. 


XXXVIII. Puccinia graminis Pers. Wheat Rust. 

Class, Teliosporeae. Order, Uredinales. Family, Pucciniaceas. 

The aecial stage of the wheat rust occurs in the spring on the leaves of 
Berberis vulgaris; the uredinial stage, known as red rust, and the telial stage, 
known as black rust, occur on the wheat plant. The infected leaves of the bar- 
berry may be preserved in 70 per cent, alcohol and the wheat leaves and stems 
may be dried or also preserved in alcohoL 


1. Study the under side of a barberry leaf containing the rust under dissect- 
ing microscope. Sketch an entire left, representing the position of the diseased 


Life History of Puccinia graminis. 

1. Teliospore with basidium (promycelium). 2. Basidiospore (Sporidium,) uninucleate. 
3. Barberry leaf with rust spots. 4. Aecium (clustercup). 5. Pycnium (spermogonium). 
6. Conidia (spermatia) from the pycnium. 7. Aeciospore (binucleate). 8. Stalk of wheat 
showing rust pustules. 9. Mycelium from which the uredospores and teliospores are devel- 
oped. 10. Uredinium with uredospores. 11. Uredospore. 12. Stalk of wheat showing 
rust pustules. 13. Telium with teliospores. 14. Teliospore. 

The aeciospore (I.), Uredospore (II.), and teliospore (III.) drawn on same scale. 

2. Under low power draw a spot showing the secia — cup-like bodies con- 
taining the aeciospores. 

3. Under low power examine a spot on the upper side of the leaf and note 
the little crater-like openings, which are the necks of hollow bodies, called pycnia 
(spermogonia), containing thread-like hyphae. Draw. 


4. By means of strips of carrot and a razor cut cross sections of the leaf, 
mount, and study under low power. Under high power draw an secium, showing 
the aeciospores. How are they developed? Draw a pycnium with conidia. 


5. Under low power, study the diseased spots on the leaves and stems of 
wheat (Triticum aestivum L.). Draw a patch, showing how the spores break thru 
the epidemis. 

6. Pick out some uredospores with a needle, or if fresh material is at hand 
cut cross sections of the stem, mount, and draw the uredospores under high 
power. The uredospores are repeating spores. 


7. Under low power draw a piece of wheat stem containing the black patches 
of teliospores. 

8. Pick out some of the teliospores, or cut cross sections of the stem, mount, 
and draw a number of spores under high power. Note that the spore is made up 
of two cells. Study variation in individual spores. 

Basidium stage. 

9. It is difficult to germinate rust spores in artificial cultures. They germi- 
nate most readily in spring when those in the field are germinating. Germinate 
teliospores in a drop culture and study the development of the promycelium 
(basidium) bearing basidiospores. Draw and describe. 

10. Describe in detail the mode of growth and life history of this rust, noting 
especially the presence of heterecism. 

XXXIX. (a) Fomes applanatus (Pers.). (Elfvingia megaloma (Lev.). 

Phylum, Mycophyta. Class, Basidiomycetse. Order, Agaricales. Family, Poly- 

This fungus is common on logs and stumps, forming semi-circular brackets 
or shelf-like bodies from a few inches to a foot or more in width. It is of a 
jrayish-brown or white color and may be collected at any season of the year. 

1. Draw the entire fruiting body and describe. The vegetative mycelium 
is in the wood from which the fruiting body projects. 

2. Under low power study a patch of the pores on the under side, by simply 
laying the fungus on the stage of the microscope and focusing properly. Draw. 

3. From a fresh specimen cut cross sections of a piece of the pore-bearing 
layer, mount, and study the basidia projecting into the cavity of the pores. How 
many spores on each bascidium. Draw a single spore. 

4. Mount some of the brown, woody mycelium from the upper part of the 
fruiting body. Draw and describe the structure of the fungus. 

5. Is the plant a parasite or a saprophyte? Notice the position of the 
hymenium (pore-bearing surface) in relation to the surface of the earth. Is the 
mycelium of the fruiting body irritable to the force of gravity? Is there any 
advantage in this? 

(b) Polystictus cinnabarinus (Jacq.). Family, Polyporacese. 

This bracket fungus is very common on dry decaying logs and branches and 
is easily recognized by its bright red color, especially prominent on the under 

1. Make a sketch of the entire fruiting- bodv. 


2. Under low power draw a patch of the lower surface showing the pores. 
Note especially the bright red color and compare it with the red color present in 
many flowers, fruits and roots. How do you explain the presence of the color? 

XL. Agaricus campestris (L.). (Psalliota). Common Meadow Mush- 

Class, Basidiomycetae. Order, Agaricales. Family, Agaricaceae. 

This edible toadstool grows in open, grassy places in fields and rich pastures. 
The so-called ''bricks" of "spawn" can be obtained from seedmen and will keep 
for some time when in a dry condition. It can be cultivated by making beds of 
the proper character in a cellar or greenhouse, or in the open air in gardens. The 
fruiting bodies may be peserved in 70 per cent, alcohol. 

1. Take some of the white filaments or strands from the ground in which the 
fungus is growing or from a brick of spawn, tease it out with needles and mount 
in water. Examine under low and high power. Note the numerous hyphse of the 
mycelium and draw. This is part of the vegetative mycelium which takes up the 
nourishment from decaying substances in the soil. 

2. Examine "button mushrooms" of various sizes and make a series of naked 
eye sketches showing how the button devolops into the mature fruiting body or 

3. Study and sketch the mature fruiting body, showing the cap or pileus 
with gills on the under side, and the stalk with the annulus. Note the irregular 
fringe at the margin of the pileus. 

4. Find the origin of the annulus and the fringe at the margin of the 
pileus by studying the veil or vellum of a fruiting body in which the pileus is just 
beginning to expand. 

5. Cut off the pileus of a mature fruiting body and place it gills downward 
on a piece of white paper. In this way a spore print may be obtained in a few 
hours. Sketch the spore print. 

6. Mount some of the spores and draw under high power. Color and 

7. Carefully cut cross sections of the gills of a pileus in which the spores 
are not quite mature. Mount and study under high power. Draw a part of the 
hymenial layer (spore-bearing layer), showing the paraphyses and the larger 
basidia. each of which bears two spores. 

XLI. Bovista plumbea Pers. Class, Basidiomycetae. Order, Lycoperdales. 
Family, Lycoperdacese. 

This puffball of a dark-brown color, when mature, is usually abundant in 
pastures, where it may be gathered in any season. It has a more or less spherical 
body, usually from one-half to one inch in diameter. 

1. Sketch one of the fruiting bodies, showing the inner peridium with an 
aperture at the apex for the discharge of the spores. 

2. Pick out some of the internal mycelium (capillitium) and after moistening 
with alcohol mount in water. Under high power draw some of the dichotomously 
branched mycelium and some of the spores. Describe. How does this plant 
obtain its nourishment? 

XLI I. Lichens. Certain fungi enter into a peculiar parasitic relation- 
ship with various species of aerial blue-green and green algae. These lichen- 
forming fungi are mostly Ascomycetae belonging to the phylum Mycophyta. 


Lichens grow on the bark of trees, on wooden fences, on rocks and on the ground. 
The common forms may be collected at any time and kept indefinitely in a dry 
condition in wooden or paper boxes. The peculiar structures called lichens are 
then simply associations of fungi and algae representing a condition of symbidsis 
known as helotism ; i. e. the lichen fungus is a slaveholder, the lichen algae are 
slaves. In the past, lichens were supposed to be an independent group of plants 
but the lichen-forming fungi will have to be distributed among the proper orders 
and families of the Mycophyta and the algae among the Schizophyta and Gon- 

(a) Parmelia cylisphora (Ach.). (P caperdta (L.) ). Subclass, Discoli- 
chenes. Order, Cyclocarpales. Family, Parmeliacese. 

This lichen is of a light green color and is very abundant on trees and fence 
boards and rails, forming large circular thalli often a number of inches in 

1. Study the naked eye characters of the thallus. Draw a part of the thallus, 
showing the margin. 

2. Soak the thallus in water and tease, out a small piece on the slide with 
needles. Study under high power. Notice two kinds of cells, colorless septate 
hyphae, the lichen fungus, and green spherical cells, the lichen algae. Draw a piece 
of the mycelium and some of the algae. To what group do the algae belong? 
How are the algae and the fungus hyphae arrange in the lichen thallus? 

3. Draw two or three algae, showing the manner in which the fungus grows 
around the green cell to obtain its food. 

4. Vegetative propagation. The alga and the fungus each reproduces itself 
in the manner peculiar to its species, but the lichen may also propagate itself 
directly by means of little granular flakes produced on the upper surface of the 
lichen thallus, known as soredia. Mount some of the granular material in water 
and examine under low power; notice in favorable speciments that the fungus 
and algae are both present in the soredium. Draw and describe. 

(b) Lobaria amplissima (Scop.). (Sticta). Subclass, Discolichenes. 
Order, Cyclocarpales. Family, Stictaceae. 

This is a foliaceous lichen of a light gray color which grows on the bark of 
trees in forests. 

1. Soak the thallus in water and note the change in color of the upper sur- 
face. Make a sketch showing the position of the brown disk-shaped or cup-shaped 

2. With a razor, cut free hand cross sections of a piece of the thallus con- 
taining an apothecium. Hold the piece between two strips of carrot. Mount the 
sections in water and under low power draw, showing the green algal layer, the 
white layer and the position of the apothecium. 

3. Under high power study the hymenial layer of the apothecium. Draw 
one of the asci containing spores. Describe. How many spores? Draw a single 
spore. Draw one of the paraphyses. 

(c) Dermatocarpon miniatum (L.). (Endocarpon). Subclass, Pyrenoli- 
chenes. Order Pyrenulales. Family Dermatocarpaceae. 

This lichen with a rather leathery thallus is common on limestone, where it 
may be obtained at any time of the year. 

1. Lay the thallus on the slide without a cover-glass and examine under low 
power. Draw a part of the thallus, showing the pores which open into the peri- 
thecia below. 


2. Cut cross sections of the thallus and mount in water. Sketch under low 
power, showing the algal and fungal layers and the perithecia. 

3. Draw one of the perithecia under high power; also an ascus containing 

(d) Cladonia rangiferina (L.). Reindeer Lichen. Subclass, Discolichenes. 
Order, Cyclocarpales. Family, Gladoniaceae. 

This lichen grows on the ground and is generally present on high wooded 
hills or slopes where it often forms large masses. 

1. Sketch and describe a large specimen. 

2. Draw a branch showing the apothecia on the branchlets. 

(e) Collema nigrescens (Leers). Subclass, Discolichenes. Order, 
Cyclocarpales. Family, Collemacese. 

A widely distributued, dark colored lichen growing on the bark of trees and 
on moss. 

1. Sketch the foliaceous body, showing the small circular apothecia. 

2. Moisten a small piece of the lichen, tease it out with needles, mount and 
note the chains of Nostoc cells and the fungus hyphse. Draw. 

3. Tease out some of the asci or cut sections, mount and draw under high 
power. How many spores in an ascus? How many cells in an ascospore? 

4. Tease out a part of a young lobe of the thallus and also cut sections; 
mount and examine for slender hyphae which are coiled at the base. These are 
the so-called carpogonia, the slender projecting part being the trichogyne. In 
the sections spermogonia, small hollow bodies, may also be found. These bear 
spermatia on the hyphal branches lining hte walls of the cavity. Draw and describe. 


XLIII. Oedogonium crispum (Hass.). Phylum, Gonidiophyta. Class, 
Confervese. Order, Oedogoniales. Family, Oedogoniacese. 

This plant grows either upon or beneath the surface of ponds and pools, 
usually attached to various solid objects. It fruits most abundantly during May 
and June, and will grow well in aquaria. 

1. Mount some of the filaments in water and examine under low power. 
Note that the filaments are unbranched and have a definite holdfast at the base. 

2. Draw one of the cells under high power, showing the chloroplast with 
pyrenoids and the nucleus. Draw the basal cell (holdfast). 

3. Nonsexual spore reproduction. If the filaments are in proper condition, 
any cell may develop into a zoospore and escape from the cell wall. Draw an 
empty cell. Draw a free-swimming zoospore and escape from the cell wall. Draw 
an empty cell. Draw a free-swimming zoospore. These have a circle of short 
flagella or cilia. Draw a zoospere which has settled down and enlarged and is 
developing a holdfast at the base. 

4. Sexual reproduction. Note the ovaries or oogonia, large cells each with 
an oosphere filled with food material. Draw. Find the opening at the base for 
the entrance of the spermatozoid. Draw a spermary or antheridium, usually con- 
sisting of two or three very short cells each of which gives rise to two sper- 

5. Look for escaping spermatozoids and for spermatozoids which have en- 
tered the oogonium. 

6. Draw an oogonium containing a ripe, thick-walled oospore. 


7. When the oospore germinates it divides into four cells, each of which 
develops into a zoospore. The zoospores settle down and develop into new 
Oedogonium plants. An attempt should be made to have oospores germinate in 
a dish of water so that the above mentioned process may be studied. If this stage 
is at hand draw and describe carefully. 

8. Write out the life cycle of this plant in the notes, giving the stages in 
proper order and noting that the plant has two definite stages in its history — 
the gametophyte and the sporophyte. 

XLIV. Oedogonium borisianum (Led.). Family, Oedogoniacese. 

This species grows in stagnant brooks or in ponds and ditches, usually attached 
to solid objects. The plants are coarse unbranched filaments and they may be 
grown in an aquarium. 

1. Mount in water and study under low power. Note the long unbranched 
filament and the basal cell expanded into a holdfast. Under high power draw 
the tip of a filament, several intermediate cells, and the holdfast. At the summit 
of certain cells broad zones with peculiar ..ring-like striations may be seen. This 
is where cell division has taken place. Draw. 

2. Draw a single cell, showing a chloroplast with pyrenoids and the nucleus. 

3. Study vegetative cells in which the zoospores are developing. These can 
be seen especially in the morning or in material which has been chilled over night. 
Draw a single, large zoospore with a circle of short flagella or cilia around the 
hyaline anterior end. 

4. Draw part of a filament, showing ovaries or oogonia, some with an 
oosphere and an opening in the wall for the entrance of the spermatozoid, and 
others with thick-walled oospores. Note one or more dwarf males attached to 
the cell below the ovary. 

5. Draw some of the so-called andro-sporangia, which consist of two to 
five short cells. These cells give rise to zoospores known as androspores, which 
settle down on the cells below the oogonia and devolop into dwarf male plants. 

6. Draw part of a filament with ovaries or oogonia and one or more mature 
dwarf males. Note the large basal cell of the dwarf male and the more slender 
spermary or antheridium composed of a number of cells. 

7. When the oospore germinates after a period of rest the cell breaks out 
in a delicate sack and divides into a four-celled body (the sporophyte) which 
gives rise ot four nonsexual zoospores. If material is at hand, study and draw. 

8. Write out a careful description of the entire life history of this plant, 
noting especially that it has an alternation of generations. 

XLV. Coleochaete pulvinata A. Br. Class, Conferveae. Order, 
Coleochaetales. Family, Coleochaetaceae. 

Several species of Coleochaete are to be found growing attached to the sur- 
face of various submerged, fresh water plants. The species mentioned above 
forms hemispherical masses of closely packed, branched filaments. These masses 
are large enough to be seen with the naked eye and should be looked for on the 
petioles or laminae of water lilies and other hydrophytes. 

1. Pick off some of the smaller and larger masses with a scalpel, mount, 
and examine under low power. Under high power draw a part of the branching 
filaments, showing the joint-like cells, each with a nucleus, chloroplast, and pyre- 
noid, and some with long ,narrow, hair-like projections sheathed at the base. 



2. Look for nonsexual reproduction by means of zoospores, a single one 
being produced in a cell. If these are present draw and find how they escape 
from the cell. 

3. Draw the mature ovary or oogonium, showing the oosphere and long 
slender, open neck. How different from Batrachospermum? 

4. Draw one of the spermaries or antheridia, which are terminal or lateal 
flask-shaped cells of peculiar form easily distinguished from the vegetative cells. 
Each antheridium produces a single, biflagellate spermatozoid. Compare with 

5. Draw a mature spermatozoid either free or in the spermary. 
6. Draw an oogonium in which the egg has been fertilized, and around which 
branches are developing from the base. 

Fig. 7. — Life Cycle of Coleochjete. 

7. Draw an ovary containing a ripe oospore and cortical layer of close- 
fitting branches. 

8. From material gathered in early spring or from prepared slides, study 
fruiting bodies in which a small sporophyte has developed by the division of the 
oospore into a number of cells. Note the advance of the sporophyte over that of 
Oedogonium. How many cells does it contain? 

9. Each cell of the small, oval sporophyte develops a zoospore, which after 
a period of activity settles down and develops into a new Coleochaete thallus. It 
is evident from the above that the entire sporophyte of Coleochaete is sporogenous. 

10. Make a diagram in the notes, showing the life cycle of Coleochaete. See 
Fig. 7. 

11. If material is at hand study the flat, disk-like thallus of Coleochate scutata 
Breb. Draw under high power and describe. 

12. Note. — The Coleochaetaceae are the Algae which are most like the plants 
of the next higher sub-kingdom. On account of the similarity of the body and 
the life cycle, the ancestors of the lowest liverworts of the present time are sup- 
posed to have been plants which, with the exception of th sexual organs, were 
something like these Algae. It must not be supposed, ohwever, that Coleochaete 
represents an intermediate ancestral stage of the liverworts; for, as will appear 
from the following study, there are very fundamental differences. 



XLVI. (a) Riccia fluitans L. Phylum, Bryophyta. Class, Hepaticae. 
Order, Marchantiales. Family, Ricciaceae. 

This liverwort has a small, linear, dichotomously branched thallus which grows 
floating in ponds and ditches. It also grows in wet places upon the ground, some- 
times in cultivated fields. The plant keeps well along with other hydrophytes in 
a covered, glass jar of water. 

1. Mount a small thallus or frond (gametophyte) in water and examine 
under dissecting microscope. Make a sketch of the plant and describe. 

2. Draw a branch of the thallus under low power, showing the air cavities 
and cellular structure. Note that this thallus is not made up of branching or inter- 
woven filaments, but that it is a true solid aggregate. Most of the thallophyes 
are either simple or complex linear aggregates. 

3. The aquatic form of this plant is usually sterile. In order to study the 
sexual organs and sporophyte to advantage, examine prepared slides of Riccio- 

(b) Ricciocarpus natans (L.). Family, Ricciaceae. 

This plant forms a small, obcordate thallus which floats on the surface of 
ponds and swamps. The individuals are hermaphrodite and develop the reproduc- 
tive organs in the spring and summer. 

1. Sketch the thallus under dissecting microscope. Describe. 

2. Under low power draw part of a section from a prepared slide, showing 
an antheridium (spermary). Draw part of a section, showing the archegonium 
(ovary) containing the oosphere. 

3. Draw an enlarged archegonium (ovary) with the spherical sporophyte, 
containing a wall one layer of cells in thickness, with the sporocytes lying free in 
the interior. 

4. From older stage draw spore tetrads and mature spores under high power. 

5. If prepared slides are not at hand, cut freehand sections of plants (with 
the aid of strips of fresh carrot roots) with male and female organs and draw 
an antheridium (spermary) and an archegonium (ovary) under low power. Also 
cut sections of a plant containing a sporophyte and some free spores. 

6. Compare the sporophyte with that of Coleochsete and note the beginning 
of sterilization of the tissue of the sporophyte. Compare also with Polysiphonia. 
The antheridium and archegonium may be compared with the plurilocular spor- 
angia of Ectocarpus. They are not at all like the sexual organs of the higher 
green algae. 

7. Make a diagram in the notes as shown in Fig. 8, which represents the 
general life cycle for all plants above the thallophytes. Note especially that the 
diagram represents a life cycle with a true antithetic alternation of generations. 




XLVII. Marchantia polymdrpha L. 

Class, Hepaticae. Order, Marchantiales. Family, Marchantiaceae. 

This thalloid liverwort is common on moist rocks and earth, especially on 
rliffs and around springs. Marchantia as well as Conocephalus and Lunularia 


£ ifyorof */£< 

Fig. 8. — Diagram showing principal stages in the life cycle of the higher 


can be kept without any trouble in a greenhouse or window garden, provided, 
they are supplied with sufficient moisture and shaded from intense light by a 
curtain. Material may be preserved in 70 per cent, alcohol or in the copper salt 


^. Take a thallus (frond) and notice its dorsiventral position on the ground. 
Make a naked eye sketch, showing the dichotomous branching, the central groove, 
and the emarginate growing points. Describe. How is it fastened to the ground? 
How does the thallus continue its development? How is vegetative propagation 

2. Under dissecting microscope study the upper surface. Notice that it is 
mapped oft" into diamond-shaped areas (areolae), each with a small opening in 
the center (air passage). Draw a patch of the surface. 

3. Study the upper surface under low power without a cover glass, by simply 
laying the thallus on the slide. Draw several areolae carefully. The areolae 
represent compartments or cavities in the upper surface of the thallus. The thallus 
should be kept moist on the under surface as it withers very rapidly. 

4. Notice the numerous rhizoids on the under surface. Where are they the 
most numerous? Mount some in water and draw the three types under high 
power — one with smooth wall, one with scattered peg-like projections in the 
interior, and one with somewhat spirally-arranged projections. Of how many 
cells does each rhizoid consist? Of what use are the rhizoids? 



5. With a scalpel or knife cut off some of the minute ventral scales arranged 
in two parallel rows on the under side and forming the central ridge. Mount and 


Life Cycle of Marchantia. 

6. Some of the thalli will show brood-bud cups. Under dissecting microscope 
or low power draw one of the cups containing brood-buds (gemmae). This is a 
special method of vegetative propagation. 

7. Mount some of the brood-buds and draw. Notice the two opposite grow- 
ing points and the place where the brood-bud was attached to its stalk. 

8. Cut cross sections of the thallus thru a cup, with a razor, and under high 
power study the development of the brood-buds. Describe. 

9. Cut cross sections of the thallus and examine under high power. Where 
is the main part of the chlorophyll? Draw part of a section, showing the walls 
of the cavities below the areolae, the peculiar chimney-like air passages, the short 
filaments containing the chloroplasts, and the cellular tissue below the cavities. 
These details can be worked out better from prepared slides, which should be 
studied if available and the free hand sections used merely, for comparison. 

10. Reproductive branches. Draw a plant with an archegoniophore and one 
with an antheridiophore. Describe both. Is Marchantia 'hermaphrodite or uni- 

11. Under high power study prepared slides of cross sections .cut at right 
angles to the surface of the disk) of the antheridiophore. Draw an antheridium 
(spermary), showing the wall, stalk, and the numerous minute cubical mother 
cells in the interior, each of which will produce two spermatids which develop into 
spermatozoids. About how many cells in each antherdium? How many antheridia 
in each disk? Do they all develop at the same time? Notice the openings to the 
pockets in which the antheridia are situated. About how many spermatozoids are 
there produced in one antheridiophore? 

12. In case no prepared slides are available, cut free-hand sections, mount 
in water, and study and draw the antheridia under low and high power. 


13. From prepared slides study sections of the arc'hegoniophore. Draw an 
archegonium (ovary), showing the lid cells, the neck, the neck canal, the venter, the 
oosphere and the incept of the perigynium (incipient perigynium). Draw the 
venter of an archegonium showing the ventral canal cell and the incipient oosphere. 

14. In case no prepared slides are at hand cut sections of the appendaged 
disk of the archegoniophore, mount in water, and study the archegonia under low 
and high power. 

15. If male Marchantia plants with properly developed antheridiophores are 
protected for several days in such a manner that no water will come onto the 
disks containing, the antheridia, active spermatozoids may be obtained in the fol- 
lowing manner : Place a drop of water on the upper surface of the disk and after 
a short time take it up with a medicine dropper and mount, or squeeze out several 
disks on a slide and mount in water. Under high power numerous motile spermato- 
zoids can be seen, each with two flagella. Study their motion for some time, then 
stain with a small drop of iodin solution and draw. 


16. Carefully pick out a young light-colored sporophyte inclosed in the peri- 
gynium, an older stalked one which appears green, and a nearly mature, yellow- 
colored one from the under side of the archegoniophore, mount in water and 
draw under low power, showing the sporangium, stalk, and foot. Describe. 

17. If fresh material is available, place a mature sporophyte, which has a 
ruptured sporangium, on a slide without cover-glass and examine. Breathe gently 
toward the specimen while making observations. Describe. 

18. Under high power draw sporocytes hanging together in chains, and spore 
tetrads from crushed sporangia, also some mature spores. Draw one of the elaters. 
What is their function? 

19. Make a diagram in the notes showing the life cycle of Alarchantia. See 
Fig. 9. 

20. Ecological Note. Describe how the air passages and the character of 
the nonsexual spores show that Marchantia is adapted to an aerial habitat. 

XLVIII. Other Thalloid Liverworts. 

(a) Conocephalus conicus (L.). Family, Marchantiaceae. 

1. Study the thallus of Conocephalus and compare in general with Marchantia. 

2. Under dissecting microscope, draw part of the surface showing the areolae 
with air passages. How do they compare in size with those of Marchantia? 

3. Under low power without cover-glass, draw an areola showing the crater- 
like air passage. Does Conocephalus have any brood-bud cups? 

(b) Lunularia cruciata (L.). Family, Marchantiaceae. 

1. Study the thallus of Lunularia and compare with Marchantia and Cono- 
cephalus. Notice especially the numerous semilunar brood-bud cups. 

2. Draw a plant under the dissecting microscope, showing several cups. 

3. Under low power draw several areolae. How many methods of vegetative 
propagation has Lunularia? Is there much need for sexual and nonsexual spore 


XLIX. Porella platiphylla L. (Bellincinia). 

Class, Hepaticse. Order, Jungermanniales. Family, Jungermanniaceae. 
This rather large, scaly liverwort is very abundant on the bark of trees. It 
may be kept for a long time in good condition in a paper box. 


L Moisten a branch of the frond in water and sketch from the upper or 
dorsal side under the dissecting microscope, showing the arrangement of the 
lateral scales. 

2. Pick off some scales, being careful so as not to tear off the small, lower,, 
ligulate lobe which may be seen under the large upper lobe of the scale. Draw 
under low power, showing both lobes of the scale. How many cells in thickness is 
the scale? Is there any midrib? Why is this scale not homologous with the 
leaf of a fern or one of the higher plants? The scales are partly analogous to- 

3. Draw a few cells under high power. Of what advantage are the thick 

4. Examine the lower or ventral side of a branch under dissecting micro- 
scope and note the semicircular ventral scales. Look for r'hizoids. Mount one 
of the ventral scales and draw under low power. 


5. Examine a frond containing little yellowish, club-shaped bodies. These 
are the sporophytes. Carefully pick out one which has the sporangium unbroken 
and one Which shows the wall of the sporangium split into four valves. Mount 
in water and draw both under low power, showing the sporangium, the foot and 
the stalk. 

6. Draw a spore and an elater under high power. 

7. Compare the thallus of Porella with that of Marchantia, noting especially 
the different ways in which the two thalli have been specialized for the work 
of photosynthesis. 

L. Sphagnum cymbifolium (Ehrb.). 

Class, Sphagnese. Order, Sphagnales. Family, Sphagnaceae. 

The peat or bog mosses grow in and near water in swamps, bogs, and other 
wet places. The species named above is unisexual, the male plant being more 
slender than the female. Collect plants with sexual organs in winter and early 
spring and sporophytes in spring and summer. 


1. Take a small mass of dry sphagnum, soak it in water and notice the enor- 
mous quantity it will absorb. 

2. Make a sketch of a female frond. Notice that the frond keeps growing 
at the top and dying below. 

3. Sketch a branch under low power, showing the arrangement of the scales. 
Draw a single scale. Is there any costa (midrib) ? 

4. Under high power draw a patch of cells from a scale, some with chloro- 
phyll and some showing the peculiar spiral and ring-shaped thickenings on the 
inner surface of the wall. 


6. Mount a piece of the main stem in water and examine under low power. 
Draw, showing a central brown cylinder and a cortical layer of clear, large cells 
with spiral thickenings. 

6. Cut off some of the clavate branches at the tip of the male plant, mount, 
and sketch under low power. Pull off the scales carefully, mount, and examine 
the antheridia (spermaries). Draw an antheridium under high power. 

7. From a female plant carefully cut out an enlarged archegonium (ovary) 
containing a young sporophyte. Mount and draw under low power, showing the 
neck at the summit. Around the base some small archegonia may usually be 
seen. Draw one of these, showing the stalk, venter, neck and lid cells. 


8. Pick out a young sporophyte showing the spherical sporangium, the very- 
short stalk and the expanded bulbous foot. 

9. Cut off one of the slender pseudopodia containing a nearly mature sporo- 
phyte. Sketch under low power s'howing the sporophyte with sporangium and 
operculum, and the expansion at the top of the pseudopodium into which the 
foot fits. 

10. Draw some of the non-sexual- spores under high power. 

11. From prepared slides make a drawing of a longitudinal section of the 
sporophyte, showing all the details of the structure. 

12. Study and draw an apical cell from a branch of the gametophyte, from 
a prepared slide. 

LI. Mosses, General Study. Class, Musci. Order, Bryales. 

(a) The juvenile gametophyte. 

When the nonsexual spore of a moss germinates it does not give rise directly 
to the mature scaly gametophyte, but develops a green filamentous pro-embryo 
known as the protonema. The protonema can always be found in connection with 
the very young moss plants which are usually present in greenhouses. The proto- 
nema may also be found by examining some of the black earth from a place 
where mosses are growing. The ripe spores of any common species of moss 
may be sown on moist soil in a box. In a few days, if the box has been covered 
with a pane of glass, an abundance of green filaments will begin to appear. 

1. Place a little earth with young moss plants into a watch glass and care- 
fully wash off the soil by means of the medicine dropper and needle. Mount the 
plantlets and any minute masses of filaments present. Examine under low power. 
Find a good protonema and draw. Notice the branching, the shape of the cells, 
and the chloroplasts. The similar brown filaments present are rhizoids. 

2. Draw a single cell, showing the wall, the cytoplasm, and the chloroplasts. 
Notice the oblique walls which may be seen in the older filaments. Where and 
how do the branches originate? 

3. Find a protonema which has developed one or more solid green buds 
from which the mature sexual moss plants will develop. Draw. 

4. With what kind of plants previously studied does the protonema com- 
pare? What then could you call the protonemal stage? How can this be used to 
explain the evolution of a moss as to habitat, form, and structure? Explain its 
evolution on this basis; remembering that the protonema is (1) a single cell, 
(2) a simple filament. (3) a branched filament; and that (4) it finally develops 
solid buds. These four stages represent the four successive steps in the evolu- 
tion of the plant body in going from the lowest unicellular forms to the liver- 


worts. Ontogeny is supposed to partly explain phylogeny. Learn the following- 
law : The history of the development of the individual is an abbreviated history 
of the development of the race to which it belongs. 

(b) The young scaly moss plant. 

Physcomitrium turbindtum (Mx.) (nearly always abundant in greenhouses, 
by roadsides, and in old fields) or a species of Mnlum will be suitable. 

i. Mount in water and sketch the entire frond under low power, showing 
die stem, scales, and rhizoids. 

2. Draw a single scale, carefully showing the costa and the margin. How 
does it differ from the scale of Porella? Under high power draw a cell showing 
the large chloroplasts and thick wall. As in the liverworts these scales are not 
homologous with true leaves. 

3. Draw a branch of a rhizoid. How do these rhizoids differ from those 
of Marchantia? What relation is there between the rhizoids and protonema? 

LI I. Polytrichum commune L. Common Hair-cap Moss. 
Class, Musci. Order, Polytrichales. Family, Polytrichaceae. 

The common hair-cap is a widely distributed moss which grows on the ground 
in old fields and meadows, on hillsides and in woods. The plants are well pre- 
served in a fruit jar with 70 per cent, alcohol, and collections s'hould be made at 
various times from winter until early summer when the sporangia are mature. 
The plants are unisexual and the material for study should include mature male 
and female plants, female plants with the embryo sporophyte developed just far 
enough to rupture the calyptra, and female plants with mature or nearly mature 

Garnet ophyte. 

1. Draw the male and female plants (fronds) of the gametophyte genera- 
tion, showing the rhizoids, scales, and tip. If the plants are dry or taken from 
alcohol, moisten in water. Note the rosette of red scales at the tip of the male 
branch and also the slender green scales at the tip of the female branch. Why 
this great difference between male and female? 

2. Take the tip of a mature male branch and dissect it with needles in a 
watch-glass, mount the detached parts and examine under low power. Notice 
the paraphyses and the white club-shaped antheridia (spermaries). Do not mis- 
take spatulate paraphyses for antheridia. Draw an antheridium under high 
power. Draw a spermatozoid from a ripe antheridium. 

3. Study the living spermatozoids. These may be obtained if suitable male 
branches are collected after several days of dry weather. Take one of the 
branches and squeeze out the antheridia onto a slide. Mount in water and ob- 
serve the motile spermatozoids. 

4. If material is at hand, study and draw antheridia from a stained perma- 
nent mount. 

5. Dissect the tip of a female plant, mount the detached parts from the 
center, and examine under low power. Draw an archegonium (ovary) under 
high power, showing lid-cells, venter, and stalk. In good specimens the oosphere 
may be seen. 

6. If convenient, study prepared slides containing archegonia. Draw, show- 
ing the stalk, venter, oosphere, neck canal, and lid-cells. 



7. Cut cross sections of the scaly stem of a large specimen (using pieces of 
-carrot and razor), mount in water and examine under high power. Draw, repre- 
senting the epidermal layer, band of peripheral sclerenchyma, inner cortical layer 
of thinner-walled cells, and central strand. 


8. Select a female plant with a young sporophyte, pull off the calyptra and 
then pull out the young sporophyte, being careful not to tear off its foot. Sketch 
the calyptra under the dissecting microscope. What does the calyptra represent? 

Sketch the young sporophyte under dissecting microscope, showing three regions — 
foot, short stem, and tip. Remember that the mature sporophyte of Marchantia 
lias three parts. 

9. Draw a mature sporophyte of Polytricum, showing the foot, the stalk 
or seta, the hypophysis, and the sporangium or capsule. What important advance 
lias the sporophyte of Polytrichum and other mosses made over those of Mar- 



Q, ©, 

Fig. 10. — Life Cycle of Polytrichum. 

•chantia and Sphagnum? Note that the sporophyte is a parasite during its entire 
life. Does it manufacture any food for itself? 

10. Cut cross sections of the seta, mount, and draw under high power, show- 
ing the epidermal layer, the band of sclerenchyma, the layer of thin-walled paren- 
chyma, and the central strand. The central strand of the sporophyte may be 
-compared with the vascular bundle system of higher plants. 

11. Ecological note. The hair-cap mosses are subject to great extremes of 
moisture and dryness. Let a gametophyte dry out and then place in water. Waht 
occurs? What adaptation has Polytricum for checking the rapidity of evapora- 
tion ? 

12. Make a diagram in the notes showing the life cycle of Polytrichum (see 
Tig. 10). 


LIII. Other Mosses. 

(a) Hypnum radicale Beauv. (Amblystegium varium (Hedw.). 

Order, Hypnales. Family, Hypnaceae. 

This is a common moss on decaying logs, in moist, shady places, and on wet 
ground. Preserve in 70 per cent, alcohol. The sporophytes are mature in summer 
and autumn. 


1. Take a nearly mature sporophyte, lay it on a slide and examine without 
cover-glass under low power. Pick off the calyptra if still attached and the 
operculum, being careful so as not to injure the delicate teeth of the peristome. 
Draw the operculum and the calyptra. 

2. Study the hygroscopic movements of the teeth of the peristome by gently 
breathing on the slide while making observations. Describe the movements. Of 
what use? 

3. Study the true stomata on the hypophysis. Make a sketch of the sporan- 
gium, showing the peristome and the hypophysis with stomata. The hypophysis 
may be compared with a leaf of the higher "plants. 

4. Cut open a sporangium longitudinally and mount. Examine under high 
power and draw a stoma, showing the two guard cells and some of the surround- 
ing cells. Draw several of the teeth of the peristome and some of the non-sexual 
spores. How many teeth are there? Are they in one or two circles? 

5. Cut a cross section of a green sporangium, mount and examine under low 
power. Sketch the section, noting the following structures : epidermis, hypo- 
dermal parenchyma, air space, spore sac, central columella. 

(b) Aulacomnium palustre (L..). 

Order, Bryales. Family, Aulacomniaceae. 

This moss is common in boggy ground and may be found on charred logs 
and stumps or on the ground. Collect the material and grow in a moist chamber. 

1. Under dissecting microscope make a sketch of a stem, modified in the 
upper art, the scales of which are easily detached. These scales act as brood 
buds, and when they fall to the ground are able to develop a protonema. 

2. Mount some of the detached scales from near the tip and draw under 
low power. 

(c) Leptobryum pyriforme (L.). Long-necked Bryum. 
Family, Bryacese. 

This interesting little moss may be found on moist, shaded cliffs and on 
rocks near water. It is often very abundant and is easily cultivated in greenhouses, 
where the gametophyte may be obtained at any season. The rhizoids contain 
peculiar tuber-like buds of a dark-brown color. On the young sterile fronds 
these tuber-like bodies are often numerous, being produced on short rhizoids 
which come from the axils of the scales. 

1. Crush the enlarged tip of a plant on the slide, mount in water and study 
under low and under high power. Draw an antheridum (spermary) and an arche- 
gonium (ovary) ; also one of the paraphyses. Note that this gametophyte is her- 
maphrodite. Compare with Polytrichum. 


2. Mount and draw a mature brood-bud under high power, showing the 
"Structure. Describe. 

3. Draw a rhizoid with an enlarged, light-colored end cell, the incept of the 


LIV. Splachnum ampullaceum L. 

Class, Musci. Order, Bryales. Family, Splaehnacese. 

Altho this odd looking moss is not very common, an attempt should be made 
to obtain fresh or preserved material of specimens containing mature or nearly 
mature sporophytes. The plant grows on decaying animal tissue or excreta and is 
said to occur in cranberry swamps from Ohio to New Jersey and northward. 

1. Sketch the entire moss, showing the gametophyte and the sporophyte with 
the sporangium and the very large, pyriform, fleshy hypophysis. Describe. 

2. Sketch the capsule and hypophysis under low power, carefully represent- 
ing the shape and surface details. 

3. Examine the surface of the hypophysis under low and high power and 
note the stomata. Draw a small portion of the surface, showing stomata. 

4. Note. — The large hypophysis covered with stomata and filled 
-with loose tissue is well fitted for the work of photosynthesis and 
may be looked upon as foreshadowing the leaf structure found in <-be 
ierns and other higher plants. 

LV. Splachnum luteum L. or S. rubrum L. 

These remarkable mosses are rather uncommon, and very few 
■will probably be able to collect specimens; nevertheless an effort 
should be made to obtain fresh or preserved material of plants with 
nearly mature sporophytes. They are reported mainly from the Rocky 
Mountain region. 

1. Under low power make a careful drawing of the sporophyte, 
showing the foot, the seta, the large umbrella-like hypophysis and 
the sporangium (Fig. 11). 

2. Draw part of the surface of the hypophysis under high power, 
showing the stomata. Are the stomata both on the upper and lower 

3. Compare the hypophyses of Hypnum radicale, Polytrichum 
■commune, splachnum ampullaceum, and Splachnum luteum and note 
the progressive development of the hypophysis as represented by these 
types. From this comparison it appears that the hypophysis may be 
regarded as a nascent, transpiratory and food manufacturing organ. 

Fig. 11. 

T „ T A .., . . T A .*, T Sporophyte 

LVI. Anthoceros laevis L. or A. punctatus L. _ 

of Splach- 

Class, Anthoceroteae. Order, Anthocerotales. Family Anthocero- num 

taceae. luteum. 

The hornworts are common on wet banks and sandstone ledges, especially 
around springs and shady places. The gametophyte is a small, lobed, more or less 


disk-shaped thallus from which the sporop'hytes * extend upward like small ver- 
tical horns. Preserve in copper salt solution. 

1. Under dissecting microscope, sketch a gametophyte containing nearly mature 
sporophytes. Note the thick tubular sheath around the base of the sporophyte. 

2. Mount a small piece of the thallus and under high power draw a cell 
showing the single large chloroplast. Compare these cells with those of Coleo- 

3. Look for endophytic colonies of a blue-green alga (Nostoc) in cavities on 
the under side of the thallus. 

4. Separate a sporophyte, which is just mature at the tip, from the gameto- 
phyte, being careful to keep the foot in a perfect condition, and sketch under low 
power. Represent the slender sporangium, the bulbous foot with wart-like out- 
growths, and the short stalk with a growing zone between the foot and sporangium 
proper. Under high power note the stomata in the green tissue toward the base 
of the sporangium. Draw. 

5. Study a sporophyte in which the tip of the sporangium has split open. 
Notice the columella. 

6. Mount some of the spores and spore tetrads and draw under high power. 
Describe the spore tetrads. 

7. If prepared slides are at hand, the details of the foot, the growing region, 
and the sporangium should be worked out. Note especially the arrangement of 
the elaters, which have a tendency to separate the cavity of the sporangium into 
tranverse compartments. 

8. Note. — The hornworts come nearer to the lowest ferns than any other 
Bryophytes and it is probable that the Bryophyte ancestors of the lowest Pterido- 
phytes were something like a horned liverwort with perhaps a chlorophyll-bear- 
ing tissue arranged somewhat like the hypophysis of a Splachnum. Anthoceros 
also points to the Pteridophytes in that it has the sexual organs embedded in the 
thallus. In Splachnum and Anthoceros together appear five structures which fore- 
shadow or anticipate important structures in the Pteridophytes. These are: (1) 
the bulbous foot and wart-like outgrowths of Anthoceros; (2) The central strand 
in the seta of Polytrichum and other mosses ; (3) the intermediate growing zone 
at the base of the Anthoceros sporangium; (4) the large hypophysis of Splachnum 
with numerous stomata; and (5) the arrangement of the spores and elaters 
(sterile tissue) in the sporangium of Anthoceros. 



LVII. Ophioglossum vulgatum L, Adder-tongue. 

Phylum, Ptenophyta. Class, Filices. Order, Ophioglossales. Family, 

This simple fern is mature about the middle of June and may be found in 
moist meadows and thickets. The entire plant should be dug up and care taken 
so as not to injure any of the roots. Preserve in copper salt solution and press 
some for herbarium specimens. Altho fresh plants are preferable, preserved or 
dry herbarium specimens will answer very well. 



1. Sketch an entire plant, carefully representing the four important regions 
of the sporophyte — sporangiophore, leaf blade, stem (short upright rhizome), 
and roots. Do the roots branch? Note the growing point at the summit of the 
rhizome from which new leaves are developed. 

2. These four parts may be compared with the organs of a Splachnum 
sporophyte in a general way as follows : 

a. The sporangiophore with the sporangium. 

b. The leaf-blade with the hypophysis. 

c. The stem with the seta. 

d. The root system with the foot. 

Compare also with Anthoceros, noting especially the growing bud in the stem.. 

3. Study the venation of the leaf under low power. Draw a. portion and 
describe. Study and draw the stomata. 

4. Mount a part of the nearly mature sporangiophore. Draw under low 
power, showing the sporangia. Under high power draw some of the nonsexual, 

LVIII. (a) Botrychium simplex Hitch. Little Grape-fern. 

Class, Filices. Order, Ophioglossales. Family, Ophioglossaceae. 

This fern is to be found in moist woods and meadows and should be gath- 
ered about the middle of June. 

1. Sketch the entire sporophyte from fresh or herbarium specimen and 
note the advance in complexity, over Ophioglossum, of the sporangiophore, leaf 
and roots. 

(b) Botrychium lunaria (L.). Moonwort. 

The moonwort is found in the northern part of the United States and 
usually grows in fields. 

1. Sketch the entire sporophyte, showing the sporangiophore, leaf, roots 
and rhizome. Describe how this plant differs from the preceding. 

(c) Botrychium neglectum Wood. Matricary Grape-fern. 

This fern grows in grassy woods and swamps and should be collected about 
the middle of June. 

1. Sketch the entire sporophyte and note the advance in complexity over 
the moonwort. 

LIX. Botrychium obliquum Muhl. Oblique Grape-fern. 

This evergreen grape-fern is widely distributed and may be collected in 
summer and autumn. Good herbarium specimens are satisfactory. 

1. Sketch the entire sporophyte and note the advance in complexity over 
the preceding in the development of the sporangiophore, leaf, and roots. 

2. Study th venation of the leaf under low power. Is there any relation 
between the development of lobes and the venation? 

3. Mount a branch of the sporangiophore and draw several sporangia under 
low power. Draw some of the non-sexual spores. 

4. Ecological note. Notice the strong root-contraction and draw under dis- 
secting microscope. How does the upright rhizome which continues to grow 
upward keep in the ground? 


LX. Botrychium virginianum (L.). Virginia Grape-fern. 
The Virginia grape-fern is common in rich woods and should be collected in 
the summer. Good herbarium specimens are satisfactory. 

1. Sketch the entire sporophyte, showing especially the extreme complexity 
of the leaf. What relation is there between the ultimate segments of the leaflets 
and the venation? 

2. Compare the last five plants in regard to the sporangiophore, the leaf- 
blade and the roots. 

3. Cut cross sections of the rhizome, mount and draw a sector under low 
power, showing the wide cortex, the endodermis, the phloem, the cambium, the 
xylem (wood) with medullary rays, and the central pith. This type of vascular 
cylinder is called a siphonostele. 

4. Cut longitudinal sections of the fleshy root tips, mount the central sec- 
tions, and draw a tip showing the apical cell. 

5. The gametophytes of the grape-ferns are subterranean and difficult to 
find. They are destitute of chlorophyll and have the appearance of minute tubers. 
If fresh or preserved material of the gametophyte of the Virginia grape-fern is at 
hand, study and sketch under dissecting microscope or low power, showing the 
general contour of the body and the rhizoids. 

6. Note. — The advance from such forms as Splachnum and Anthoceros to 
Ophioglossum represents a vertical evolution, i. e., evolution upwards. The 
development indicated in passing thru the series of forms from Ophioglossumi 
vulgatum to Botrychium virginianum represents a horizontal evolution. There 
is a close relationship among these ferns. It must not be supposed, however, 
that the latter has necessarily been derived directly from the former, but only 
that the ancestors of Bothrychium were at one time in a condition as simple as 
Ophioglossum is at the present time. 


LXI. Ferns. 

(a) Adiantum capillus veneris L. Venus-hair Fern. 

Phylum, Ptenophyta. Class, Filices. Order, Filicales. Family, Polypodiaceae. 

The venus-hair fern grows in ravines and is widely distributed, but very 
rare in the North. It grows very readily in greenhouses, and is extensively 
cultivated. The gametophytes may be found at almost any time on pots in 
greenhouses. They may be raised in large quantities by sowing spores on any 
well-prepared, moist ground. 


1. Mount a fresh, heart-shaped thallus in water and sketch it from the 
upper side under dissecting microscope. 

2. Study the rhizoids under low power and draw a single one under high 
power. Are they unicellular or multicellular? 

3. Under high power draw a single cell of the thallus, showing the chloro- 

4. Examine the lower side carefully under low power and note the numer- 
ous antheridia (spermaries) and archegonia (ovaries). How are these organs 
distributed over the thallus? Under high power draw an antheridium and an 
archegonium (so much as can be seen of them above the surface of the thallus). 
Compare the thallus of Adiantum with Anthoceros and Marchantia . Note 
especially the comparatively small size of the gametophyte and that it is 


5. Look for the large, spirally coiled spermatozoids moving in a ripe anther- 
idium. Study free-swimming spermatozoids and draw. Describe the movement. 
The spermatozoids can usually be found on gametophytes of proper size and 
are often present in large number. Iodin will bring out the flagella. 

6. If prepared slides are available, draw a section of a nearly mature anther- 
idium, showing spermatozoids in various stages of development; also draw an 
archegonium, showing the neck, venter and oosphere. 

7. Study young gametophytes and recently germinated spores. Note the 
protonema. Draw. Compare with the Bryophytes. 


8. Sketch and describe the compound leaf. 

9. Mount and draw a single leaflet under dissecting microscope, showing 
the general outline and the free, dichotomous venation. How does the character 
of the venation explain the notched and cut margin? Can the origin of the 
leaflets be explained from the same standpoint? Note that the tips of some of 
the lobes are bent under so as to cover the sporangia. 

10. Under high power study and draw the stomata. Are they on the upper 
or lower surface or on both? Draw a single cell, showing the chloroplasts. 

11. If slides are at hand draw a section of a young sporophyte embryo,, 
showing four definite regions (quadrants). 

12. Pick out a young sporophyte from the under side of an old gametophyte, 
and draw under low power. Show the four regions, first leaf, root, bud and 
foot. Note that the young sporophyte is parasitic on the parent gametophyte, 
and that it acquires its independent life gradually. 

13. Cut sections of the rhizome, stain and mount or use prepared slides. 
Note the general ground tissue and several, scattered, concentric vascular bundles- 

(b) Pteridium aquilinum (L.). (Pteris). Eagle-fern. 

Family, Polypodiacese. 

The eagle-fern grows on hillsides, especially in sunny places. The rhizomes 
should be preserved in alcohol. 

1. Cut cross sections of the rhizome, mount, and sketch under dissecting 
microscope, representing the following structures; the band of external or corticaL 
sclerenchyma, the pith or ground tissue, internal sclerenchyma (stereome) in two 
large, brown bands and in smaller patches, and the concentric fibro-vascular bundles 
— usually three large ones and a number of smaller ones. Note the two lateral 
ridges. How do you account for the dorsiventral condition of the rhizome? This 
type of vascular system is known as a polystele. 

2. Under high power, make a careful drawing of one of the smaller vascu- 
lar bundles, showing the bundle sheath, usually brown, the phloem and the central 
xylem (wood). 

3. Test for starch with iodin solution. Draw some of the ground tissue,. 
showing the intercellular spaces, and starch in the cells. 

4. Draw a patch of cells from the internal and from the external scleren- 
chyma, showing the thick cell walls. 

5. Cut longitudinal sections of the rhizome, mount and draw, comparing the 
structures with those seen in the cross section. Also draw a single cell from the 
external sclerenchyma, the internal sclerenchyma, and the ground tissue. From 
the vascular bundle, draw a sieve tube and a scalariform tracheid. 



6. Describe the mode of growth of the Pteridium rhizome. What advantages 
in the geophilous habit? Has this rhizome any advantage over the vertical rhi- 
zomes of Ophioglossum and Botrychium? 

7. Carefully remove the leaves from the apex of a branch of the rhizome and 
cut cross sections of the growing point. Mount the sections, and in the first two 
or three look for the apical cell. Draw. Cut longitudinal sections of the apex of 
another branch, mount and draw the section, showing the apical cell. What is the 
shape of the apical cell? 

8. Under dissecting microscope draw a leaflet of Pteridium from the lower 
side, showing the membranous false indusium formed of the reflexed margin of 
the leaflet. 

9. If fresh, young leaves are at hand, study the nectar glands with drops of 
nectar in the axils of the main divisions. Locate them and draw. Of what use 
are the nectaries? 

(c). Cyrtomium falcatum J. Sm. 
Family, Polypodiacese. 

Cyrtomium grows readily in greenhouses and window gardens, and fresh 
sporangia may be obtained at almost any time of the year. 

1. Examine a sterile leaf and a sporophyll. Draw one of the leaflets showing 
the circular sori on the under side. 

Fg. 12. — Life Cycle of Ordinary Fern. 

Pick off some of the sori which have recently exposed the sporangia, 
examine without cover-glass and describe how the spores are scattered. 

3. Mount an indusium and some opened and unopened sporangia. Draw the 
indusium under low power. 

4. Draw a single sporangium under high power, showing the stalk, annulus, 
and lip cells. Contrast this sporangium with the one in Botrychium. Draw some 
of the nonsexual spores. Note shape, color and surface. 

5. Make a diagram in the notes showing the life cycle of a fern. See Fig. 12. 


LXII. Other Ferns. 

(a) Camptosorus rhizophyllus (L.). Walking-fern. 
Family, Polypodiacese. 

The walking-fern is common on rocks, especially on limestone. Study fresh 
or herbarium specimens. 


1. Sketch a plant with several leaves, some of which have rooted at the 
long acuminate tips, and show plantlets of various sizes. This is a simple and 
effective method of vegetative propagation. Leaves are usually highly specialized 
organs which have to a large extent lost the power of reproducing the individual. 
There are, however, many cases, like the present one, even in the higher plants, 
where the leaves retain the power of reproduction to a remarkable degree. 

(b) Filix bulbifera (L,). (Cystopteris.) Bulbiferous Bladder-fern. 
Family, Polypodiaceae. 

This fern grows on moist rocks, especially limestone, and is easily cultivated 
in greenhouses, where it propagates itself extensively. 


1. Sketch a leaf showing a number of fleshy brood-buds (bulblets). On 
which side of the leaf are they developed? 

2. Under dissecting microscope draw a brood-bud which has just fallen off. 

3. Draw a young fern plant which is developing from a brood-bud. Is this 
an efficient method of vegetative propagation? Why? 

(c) Marattia douglassii (Presl.). Order, Marattiales. Family, Marat- 

This fern may be obtained in large greenhouses and conservatories. Use 
either fresh or preserved material. 

1. Draw a leaflet showing the peculiar sori. 

2. Draw a single sorus under low power and describe. This is a eusporan- 
giate fern. How do the sori and sporangia differ from those of Cyrtomium? 

LXIII. Lycopddium lucidulum Mx. Shining Club-moss. 

Phylum, Lepidophyta. Class, Lycopodieae. Order, Lycopodiales. Family 

This lycopod grows in moist woods and on shady cliffs. Use fresh, alcoholic, 
or herbarium material. 


1. Sketch the entire plant. Note the dichotomous branching, the alternating 
zones of sporophylls and sterile leaves, and the dichotomous roots. 

2. Draw a branch, showing very carefully the tip and several zones of sporo- 
phylls below. Note that the formation of sporophylls does not stop the growth 
of the axis on which they are produced. Which are the larger, sporophylls or 
sterile leaves? 

3. Draw a single sporophyll with sporangium under low power. 

4. Under high power draw several non-sexual spores. 


5. From alcoholic material cut cross sections of the stem, mount, and draw- 
under lower power. Note the epidermis with cuticle, the wide cortical layer, the 
vascular bundles of the leaf traces, the bundle sheath or endodermis, and the 
central cylindrical mass of vascular tissue. Inside of the endodermis are a number 
of more or less parallel strands of xylem and phloem. These structures will be 
more prominent after staining with iodin solution. This type of vascular system 
is called a protostele. 

6. Cut radial longitudinal sections of the stem and compare in detail with the 
•cross section. 

7. Vegetative propagation. Notice the peculiar bulb-like brood-buds near the 
tips of some branches. Pick off one and draw under dissecting microscope. 

LXIV. Lycopodium obscurum L. Tree Club-moss. 

Lycopodium obscurum grows in moist woods, forming long slender rhizomes 
which creep under the surface of the ground or under leaf mold. From this 
rhizome upright, serial branches develop. 


1. Sketch an entire plant showing the rhizome and upright branch bearing 
a number of cones. 

2. Draw a single cone under dissecting microscope. Note the spiral arrange- 
ment of the specialized sporophylls, and that by the development of a cone the 
further development of the axis is stopped. What is the probable reason for this? 

3. Under low power draw a single sporophyll showing the sporangium. 
Note the advance in specialization of this sporophyll over that of the preceding 

4. Under high power draw some of the nonsexual spores ; also some of the 
spore tetrads from younger sporangia. 

5. Note. — This cone represents a primitive flower. Compare it with the 
zone of sporophylls in the preceding species. 

LXV. (a) Equisetum arvense L. Field Horsetail. 

Phylum, Calamophyta. Class, Equisetese. Order, Equisetales. Family, Equise- 

The field horsetail is common along roadsides and railways, on river banks 
and steep slopes facing the north. The fertile branches come up in April and 
May, while the sterile ones begin to appear at about the same time, but do not 
reach their full development until later in the season. Spores may be collected 
in large quantities and kept in a dry glass bottle. Rhizomes with fertile and 
sterile branches should be preserved in 70 per cent, alcohol. Good hebarium 
specimens may also be used. 


1. Sketch a plant containing the rhizome, fertile shoot with cone, and young 
sterile shoot. Note the whorls of scale-like leaves at the nodes ; also the lack of 
chlorophyll in the fertile shoot. 

2. Sketch a mature sterile shoot. 

3. Note and describe the division of labor in the stem of this plant — rhi- 
zome for a food storehouse and for vegetative propagation, fertile branch for the 
production of non-sexual spores, sterile branch with abundant chlorophyll for food 
manufacture. From whence is the food material obtained which goes to form 


the fertile shoot? Compare the stems of Lycopodium lucidulum, L. obscurum and 
Equisetum arvense and note the degree of differentiation in each. 

4. Cut off some of the peltate sporophylls, mount and draw from the side 
under dissecting microscope. Show the stalk, the angular outer expansion and 
the sack-like sporangia hanging from the under side. How are the sporophylls 
arranged in the cone? Compare this cone and the sporophylls with those of Lyco- 
podium obscurum. Compare also these two sporophylls with a fern sporophyll. 

5. Place a small flake of the dry spores on a slide without water or cover- 
glass, breathe on them gently until the glass becomes moist, and examine imme- 
diately under low power. Note the spores with appendages coiled about them. 
In a few moments the spores will be in violent agitation, while the appendages 
uncoil. Breathe gently on the slide while looking into the microscope. How many 
appendages on each spore? Draw. Describe in detail the hygroscopic prop- 
erties of the appendages. Of what advantage to the plant is this peculiar ar- 

6. Cut cross sections of a young fertile branch from alcoholic material. 
Mount, stain with iodin solution and draw under low power. Note the epider- 
mis, the wide cortical layer with a circle of lysigenous cavities the endodermis, 
the circle of vascular bundles, and the pith with a large central lysigenous cavity. 
The xylen (wood) of each vascular bundle is arranged somewhat in the form of 
a V, the apex of the V being occupied by a large air-cavity. The two limbs of 
the V end near the endodermis, and the phloem is situated between these two 
masses of xylem. 

(b) Equisetum hyemale L. Scouring Rush. 

This plant grows in wet places along the banks of rivers, creeks and lakes. 

1. Examine the fresh or dry stems under low power. Notice the parallel 
grooves and ridges, with lines of tubercles and stomata. Draw and describe. 

2. Break some of the dry stems and note their brittleness. Burn one of 
the stems in a hot flame, mount the outer part of the shell which remains, and 
examine under low power. Notice that the cell walls and stomata are still distinct. 
This is because the cell walls are impregnated with silica. Draw a flake showing 
the stomata. 

. 3. Note. — The cavities often contain water or ice in the winter. 

LXVI. Marsilea quadrifolia L. European Marsilea. 

Phylum, Ptenophyta. Class, Hydropteridse. Order, Marsileales. Family, 

This water fern grows well in artificial ponds, in gardens and greenhouses. 
The western Marsilea vestita H. & G. found in wet places and shallow ditches on 
the great plains and prairies of the interior may also be used. The sporophytes 
are mature in autumn. 


1. Sketch a branch of the creeping rhizome, showing the roots and the 
leaves with slender upright petioles. 

2. Sketch a sporophyll with two sporocarps. 

3. Carefully cut off part of the thick inner margin of some sporocarps and 
place them in a glass of water. In a day or two a gelatinous ring will be ex- 


truded on which are situated the sack-like sori in which microsporangia and mega- 
sporangia are contained. Draw. 

4. Mount some of the microsporangia and megasporangia and draw each 
under low power. The megasporangium contains a single megaspore; the micro- 
-sporangium a considerable number of microspores. 

5. Under high power draw a single microspore and megaspore, in correct 


6. In the meantime the spores will begin to develop the gametophytes. These 
.are very minute, and the spores in the water should be examined every few hours 
in order to get the proper stages. The male gamtophyte develops entirely in- 
side of the microspore wall and the female gametophyte merely protrudes the neck 
of the archegonium (ovary) from one end of the spore. Draw a male gameto- 
phyte with a protrusion on the side of the spore wall for the escape of the sper- 
matozoids and a female gametophyte with archegonium projecting from one end, 
showing a large number of spermatozoids in the gelatinous substance extending 
from the neck of the archegonium. Why does the microspore always give rise 
to a male plant, and the megaspore to a female? 

7. If prepared slides are at hand, study and draw sections of nature male 
•and female gametophytes. The male gometophytes correspond to the pollen grain 
of seed plants, and the female gametophyte to the embryo-sac in the ovule. Both 
gametophytes of Marsilea must be compared with the hermaphrodite gametophyte 
of Adiantum. Note especially the great reduction in size; also that after this 
there will be no more hermaphrodite gametophytes, hence no possibility of self- 

8. In a week or so the female plants in the glass of water will have embryo 
sporophytes. Draw under low power and describe. 

9. Ecological Note. — Examine a plant at night, or place a flower-pot with 
a living plant in a dark chamber and note the manner in which the leaflets fold 
up. How long does it take the leaflets to unfold after being placed in sunlight? 

LXVII. Salvinia natans (L.). Salvinia. 

Class, Hydropteridse. Order, Salviniales. Family, Salviniacese. 

This floating water fern grows readily in aquaria in greenhouses. 


1. Draw an entire plant as it floats on the surface of the water, showing the 
horizontal stem, the leaves, and the peculiar root-like leaves hanging down from 
the underside. 

2. Take out some of the plants and throw them into water. Note how 
they nearly always turn right side up. 

3. Place a leaf on the slide and examine without cover-glass under low 
power. Draw a part of the surface showing the peculiar hairs. What is their 

Mount one of the dissected, root-like leaves and sketch under low power. 
5. Ecological Note. — Describe the various ways in which the sporophyte of 
Salvinia is adapted to its environment. 

LXVIII. Isoetes melanopoda J. Gay. Black-based Quillwort. 

Phylum, Ptenophyta. Class, Isoeteae. Order, Isoetales. Family, Isoetacaeae. 
This quillwort may be found in moist prairies and overflowed fields in the 


central states of the Mississippi Valley. Fresh or herbarium specimens may be 
used, and stems preserved in 70 per cent, alcohol. 


1. Sketch and describe the entire sporophyte, showing leaves, short stem, and 

2. Study prepared slides or cut cross sections of stems in alcohol and draw, 
showing the following structures : the two vertical furrows and two large lateral 
lobes, the outer cortex and extensive parenchymatous tissue in which the cells 
are arranged in radial rows, on the inner limits of this layer a zone of meristem- 
atic cells, inside of this a layer of clear cells (the phloem, "prismatic layer") and 
in the center a xylem-cylinder from which bundles pass outward to the leaves. 

LXIX. Sigillaria sp. 

Phylum, Lepidophyta. Class, Selaginelleae. Order, Sigillariales. Family, 

Fossil impressions of the trunks of large, arboreous Sigillarias are common 
in the formations of the carboniferous period and may be seen in most museums. 

1. Sketch the surface of part of a trunk of Sigillaria, showing the leaf scars 
and the longitudinal fluting. 

2. Note. — The heterosporous pteridophytes of the present time are the rem- 
nants of a once great group of plants which formed a characteristic vegetation 
before and during the carboniferous period, which ended millions of years ago. 

LXX. Selaginella kraussiana (Kunze). Krauss' Selaginella. 

Phylum, Lepidophyta. Class, Selaginelleae. Order, Selaginellales. Family, 

This plant grows very luxuriantly in greenhouses and window gardens, if the 
soil is provided with proper moisture. Suitable material may be had at any time 
of the year. 


1. Sketch an entire plant, showing branches, leaves, and roots. Note that 
the branches occur only in one plane and that the roots are dichotomous. Describe 
the character and arrangement of the leaves. How do you account for the 
arrangement? How does the plant accomplish vegetative propagation? 

2. Draw a leaf under low power. Under high power draw a cell, with a 
single chloroplast and one with several chloroplasts. Draw also one of the 
stomata. Where are the stomata situated? Look for the ligule on the leaf. Of 
what use is the ligule? 

3. Cut cross sections of a fresh stem or of stems preserved in alcohol, 
mount, and draw, representing the following structures: epidermis, cortical tissue 
in which may appear sections of bundles passing to the leaves, two or more large 
air spaces, and in the center of each space a vascular bundle. The bundle consists 
of a central strand of xylem (wood) surrounded by a band of phloem which is 
enclosed in a large-celled bundle sheath. Note the strands of cells passing through 
the air space from the cortex to the vascular bundle. 

4. Draw one of the short bisporangiate cones (primitive flower) under 
dissecting microscope, showing microsporophylls above and one or more mega- 
sporophylls below. 

5. Carefully pick off a microsporophyll and a megasporophyll each with its 
sporangium, mount and draw under low power. Note the greater specialization 



in the arrangement of the sporangia over that of Marsilea. How many mega- 
sporophylls in comparison with the microsporophylls on each cone? Note the 
numerous microspores in the microsporangium. How many spores in the 
megasporangium ? 

6. Draw a microspore and a megaspore in exact proportion under low power. 
How do you explain this difference in size of the nonsexual spores? Determine 
how many times greater in volume the megaspore is than the microspore. How 
many megaspores and microspores in one cone? 


7. From prepared slides draw the male and female gametophytes of 
Selaginella, the archegonium (ovary) and antheridium (spermary) and the 
oosphere and spermatozoid. Why does the microspore always produce a male 

Fig. 13. — Life Cycle of Selaginella. 

and the megaspore a female gametophyte? Compare with Note 12 under 
Vaucheria. Observe also that the determination of sex in these plants, as well as 
all other heterosporous groups, has no relation to the reduction division. 

8. Draw and describe a young sporling showing root, stem and first leaves 
with megaspore still attached containing the female gametophyte and foot of the 

9. Make a diagram in the notes showing the life cycle of Selaginella. 
See Fig. 13. 

10. Note. — It will be remembered that in the lowest archegoniates the 
gametophyte is the important plant in the life cycle, and that the sporophyte is 
very small. Now in the highest forms the tables are turned and the sporophyte 
has become the plant. Between such plants as Isoetes and Selaginella on the one 
hand and the lowest living seed plants on the other, there is a considerable hiatus, 
nevertheless it is not difficult to trace the transformation which was necessary in- 
passing from the condition of heterosporous pteridophytes to the lowest gymmo- 



XV. Anthophyta \ Dicotylae — Dicotyls. 

(Flowering Plants) j Monocotylae — Monocotyls. 

XIV. Strobilophyta . ...( Gneteae — Joint-firs. 
(Strobilus Plants)/ Coniferae — Conifers. 

Ginkgoeae — Maiden-hair 

Cordaiteae (Fossil) — Cor- 

Cycadeae — Cycads. 
Pteridospermae (Fossil) — 


XIII. Cycadophyta ... 

(Cycad Plants) 

XII. Lepidophyta 

(Scale-leaf Plants) 

XL Calamophyta 

(Calamite Plants) 

X. Ptenophyta <J 


IX. Bryophyta 



"VIII. Mycophyta ...,..< 

(True Fungi) 

VII. Charophyta ( 

(Stoneworts) j 

VI. Rhodophyta \ 

(Red Algae) j 


V. Phaeophyta { 

(Brown Algae) 

Selaginelleae — Selaginellas. 
Lycopodieae — Lycopods. 

Sphenophylleae (Fossil) — 
Wedge-leaf Calamites. 

Calamariae (Fossil) — 

Equiseteae — Horsetails. 

Isoeteae — Quillworts. 
Hydropteridae — Water-ferns. 
Filices — Ferns. 

Anthoceroteae — Hornworts. 
Musci — True Mosses. 
Andreaeae — Granite Mosses. 
Sphagneae — Bogmosses. 
Hepaticae — Liverworts. 

Basidomycetae — Basidium 

Teliosporeae — Brand Fungi. 
Laboulbenieae — Beetle Fungi. 
Ascomycetae — Sack Fungi. 

Chareae — Stoneworts. 

Florideae — Red Seaweeds. 


Cyclosporeae — Rockweeds. 

Phaeosporeae — Kelps. 

Dicotylae — 




Conf erveae — Confervas. 
Siphoneae — Tube Algae. 
Archemycetae — Primitive 


IV. Gonidiophyta 

(Zoospore Plants) 

III. Zygophyta \ Conjugatae. 

(Conjugate Algae) | Diatomeae — Diatoms. 

II. Myxophyta C Myxomycetae — Slime Molds. 

(Slime Plants) / Plasmodiophoreae. 

I. Schizophyta . . . 
(Fission Plants) 

Myxoschizomycetae — Slime 

Schizomycetae — Fission Fungi. 
Cyanophyceae — Blue-green 




LXXI. Cycas revoluta L. Cycad. 

Phylum, Cycadophyta. Class, Cycadeae. Order, Cyadales. Family, Cycadaceae. 
This plant is usually grown in greenhouses and conservatories. Herbarium 
and museum material should also be at hand. 

1. Examine a living plant and describe its general character. Sketch the 
stem, showing the scale leaves and one foliage leaf. 

2. Draw a megasporophyll (carpel) from herbarium specimens, showing the 
megasporangia or ovules. Note the similarity of the carpel to the foliage leaves. 
The carpels are produced in a whorl like the foliage leaves, and the stem 
continues to grow thru the whorl. Compare this condition with the ordinary ferns 
and with Lycopodium lucidulum. 

3. Make a sketch of the large staminate (microsporangiate) cone. Draw a 
single microsporophyll (stamen), showing the numerous microsporangia on the 
under side. 

4. From alcoholic material draw a young ovule, properly dissected, showing 
the integument with micropyle, the inner wall of the ovule (megasporangial wall) 
with the pollen chamber, and the female gametophyte. 

5. Draw half of a la'rge female gametophyte from a mature seed, showing 
the little depression at the outer end and the dormant sporophyte embryo. The 
necks of the archegonia open into this depression (called the arc'hegonial chamber) 
at the time of fertilization. 

6. Mount male gametophytes (pollen-grains), and draw under high power. 

7. If prepared slides are available study sections of pollen-grains showing 
the internal structure. 

8. Note. — The fundamental difference between the heterosporous pterido- 
phytes and the lower seed plants is that in the latter the microspores and mega- 
spores are not shed, but develop the male and female gametophytes in the micro- 
sporangia and megasporangia respectively, while in the former the spores sooner 
or later drop to the ground. The female gametophyte remains permanently 
enclosed in the megasporangium, but the male gametophytes are shed from the 
miscrosporangia and some fall into the micropyle of the ovule. This is known 
as pollination. In order that the spermatozoids may fertilize the oospheres in 
the archegonia a short pollen tube must grow thru the tissue between the pollen 
chamber and the female gametophyte. It will be observed that the gametophytes 
are now entirely parasitic, the female in the ovule and the male at first in the 
microsporangium, and after pollination, in the wall of the ovule. 

LXXII. Ginkgo triloba L. Maiden-hair-tree. 

Phylum, Cycadophyta. Class, Ginkgoeae. Order, Ginkgoales. Family, Gink- 

This beautiful tree, a native of China and Japan, is cultivated quite exten- 
sively in the United States. Museum and herbarium material may be used. 

5 (65) 



1. Sketch a leafy branch, showing the leaves developed in clusters on dwarf 
branches. Note that dwarf branches may give rise to ordinary branches. 

2. Sketch a single leaf under dissecting microscope, showing the dichotomous 
venation. Compare the venation with that of the Adiantum. leaf. 

3. Sketch a stamen (microsporophyll) under lower power. How many 
microsporangia ? Compare with stamen of Cycas. Sketch a carpel (megasporo- 
phyll) and compare with the Cycas carpel. 

4. Sketch a mature fleshy seed on its long stalk. Note the collar or cup 
around the base of the seed and the small undeveloped ovule. On some stalks 
two seeds develop. Remove the fleshy part of the integument and note the hard, 
inner layer. 


5. Draw a male plant (pollen-grain) under high power. 

6. From alcoholic material study the mature female gametophyte (kernel of 
the seed). Sketch, and compare the size of the male and female gametophytes. 

7. Carefully cut longitudinal sections from one side of the female gameto- 
phyte until the embryo sporophyte comes into view, and sketch the section under 
dissecting microscope, showing the embryo in position. 

LXXIII. Conifers. General Study. 

Phylum, Strobilophyta. Class, Coniferse. Order, Pinales. 

The conifers called for below are cultivated quite extensively, and material 
for study can usually be obtained without difficulty. 

(a) Various Conifers. 

Collect branches of the following: Pinacese — Norway spruce (Picea dbies 
(L.), Canadian hemlock (Tsuga canadenis (L.), European larch (Larix larix 
(L.). Juniperaceae — arborvitae (Thuja occidentatis L.) 

1. Sketch a short branch of the Norway spruce and note a slight tendency 
to bilateral symmetry, and how the leaves are bent from the under side to obtain 
a proper light relation. 

2. Sketch a branch of the Canadian hemlock with carpellate cone at the end. 
Note bilateral arrangement and the light relation of the leaves, especially the 
small ones on the upper side. 

3. Sketch the larch branch showing the large dwarf branches. Compare 
with Ginkgo. Note that the foliage leaves are deciduous annually, and that the 
dwarf branches may develop into ordinary branches. Are the dwarf branches 
deciduous (self-pruned) ? 

4. Sketch a small branch of the arborvitae. Note the flattened condition of 
the stem and the leaves. Note also that numerous branches of various sizes 
are self-pruned. 

(b) Pinus. Family, Pinaceae. 

Collect large branches of white pine (Pinus strobus L.) pitch pine (P. rigida 
Mill.) Austrian pine (P. lavicio Poir.), and Scotch pine (P. silvestris L.) Also 
collect the dwarf branches with needle-leaves which have been self-pruned. 

1. Study and sketch a branch of the Austrian pine, showing scale leaves, 
dwarf branches, and foliage leaves (needles). How old is the branch studied? 
What two ways of telling the age? Are the foliage leaves deciduous? How old 
are the dwarf branches before they are self-pruned? Where do the ordinary 
branches originate, and when ? 


2. Draw a dwarf branch, with scale leaves and foliage leaves, of the white 
pine, pitch pine, Austrian pine, and Scotch pine. Note the pecularities of each 
dwarf branch. Compare with Larix and Ginkgo. 

3. Under low power, without cover-glass, draw part of the foliage leaf of 
the Austrian pine, showing the stomata. How are they arranged? Draw a scale 
leaf from the ordinary branch and one from the dwarf branch. Note the 
difference between the foliage leaves and the scale leaves. 

4. Cut cross sections of a foliage leaf, mount and study under low power. 
Draw and note the following tissues : epidermis with sections of the stomata, 
heavy-walled hypodermal tissue, green mesophyll with a number of resin-ducts, 
a limiting layer of large clear cells, and the light-colored central region with two 
vascular bundles. 

(c) Structure of White Pine Stem. 

Preserve pieces of branches, one to six years old, in alcohol^ and also obtain 
large, polished cross sections (about two inches thick) of a tree-trunk with bark. 

1. With a strong, sharp razor, cut cross, tangential and radial sections of 
stems in alcohol, mount, and stain with iodin ; or study prepared slides. 

2. Draw part of a cross section under low power, showing epidermis, cortex, 
with resin passages, phloem, cambium, xylem in a number of annual rings with 
medullary rays and resin passages, and central pith. 

3. Radial section. Draw under low power, showing cortex, cambium, xylem 
(composed of the tracheids), and pith. Note the medullary rays passing from the 
pith to the phloem. 

4. Tangential section. Draw under low power, showing part of the xylem 
with tracheids and cross sections of the medullary rays. 

5. Under high power draw part of a tracheid from radial section, showing 
the peculiar bordered pits. 

6. Sketch part of a polished section of an old pine stem, showing bark, 
cambium, sap wood, heart wood, and pith. Notice the medullary rays. Notice 
also that each annual ring of wood is double — early wood and late wood. On 
which side is the early wood? Describe the growth of a pine tree in height and 

(d) Sporophylls of Pinus laricio. 

Use fresh or alcoholic material. 

1. Draw a staminate (microsporangiate) cone under dissecting microscope. 
Describe the arrangement of the stamens (microsporophylls). 

2. Draw a stamen under low power, showing the outer (under) side with 
two microsporangia (pollen-sacs). How different from the microsporophyll of 
Selaginella in structure and function ? 

3. Draw a young carpellate (megasporangiate) cone under dissecting micro- 
scope. Describe. Note that the parts are smaller at the lower end. 

4. Draw a carpel (megasporophyll) from the lower side under low power, 
showing the bract (true leaf blade of the carpel) and the large ovuliferous scale. 
This may be an outward growth of the chalazal region of the ovules. Draw the 
carpel from the inner (upper) side, showing the two ovules (megasporangia) and 
the ovuliferous scale. Compare the carpel with the megasporophyll of Selaginella. 

5. Draw a mature carpellate cone. Note the spiral arrangement and that 
the carpels at the base are undeveloped and contain no seed. This is an example 
of rudimentary organs. If a rudimentary organ was formerly more highly 
developed and functional it is called a vestigial organ or a vestige. 


6. Note. — The staminate and carpellate cones of the pine represent primitive 
flowers. Are these flowers monosporangiate (one kind of spores in the flower) 
or bisporangiate (both kinds of spores in the same flower) ? Compare with the 
cone in Selaginella. Is the pine tree (sporophyte) monecious or diecious? 

(e) Carpellate Cone of Larix larix. 

Collect carpellate cones of the usual type and some which have the tip 
continued as a leafy branch. Preserve in alcohol. 

1. Sketch a normal cone in which terminal growth has been completely 
checked. , 

2. Sketch a cone on which a leafy branch has developed at the outer end. 
Note the gradual transition from carpels to ordinary foliage leaves. Sketch a 
number under dissecting microscope, showing this transition. This continued 
growth or prolongation of the floral axis of the larch cone is a good example of 
reversion to a more primitive condition or atavism. Compare with the ordinary 
ferns, Lycopodium lucidulum, and Cycas. 

3. Observe fresh or dried, young cones and note the presence of a special 
color. How do you account for the color in this cone? 

(f) Gametophytes and seed. 

The gametophytes of Pinus laricio may be studied from staminate and car- 
pellate cones preserved in alcohol. The seeds may be kept in a dry condition. 

1. Draw a male gametophyte (pollen-grain) under high power. Note the 
two wings. These represent an adaptation for anemophilous pollination. 

2. Remove the female gametophyte from a young seed (collected at the 
time of fertilization, about July 1), and draw under dissecting microscope. Note 
the difference in size between the male and female gametophytes. Compare the 
two gametophytes with those of Marsilea and Selaginella. 

3. Draw a mature seed. Remove the testa and the inner seed coat. What 
does the inner coat represent? Draw the female gametophyte. Carefully cut out 
the embryo sporophyte, which is now in a dormant condition. Sketch under dis- 
secting microscope, showing the radicle, suspensor and cotyledons. Pick off the 
cotyledons from one side and sketch the plumule. How many cotyledons ? Instead 
of P. laricio, the seeds of Pinus edulis Engelm, the nut pine of commerce may be 
used to advantage. 

4. If prepared slides are at hand draw a section of a stamen, showing the 
one-called microspores. 

5. Draw a section of a male gametophyte (or study mature pollen-grains 
preserved in alcohol) showing the large tube cell and nucleus, the generative cell 
and the two disorganized vegetative cells lying like two thin plates against the 
wall of the grain back of the generative cell. 

6. Draw a section of a young ovule, showing the functional megaspore. 

7. Draw a pollen-grain which has formed a short pollen-tube growing down 
into the nucellus (tip of the megasporangium). Note the tube nucleus in the 
tube and in the body of the grain the spermatogenous cell, the stalk cell and the 
remains of the two evanescent vegetative cells. The spermatogenous cell divides 
later into two sperm cells which do not have flagella or cilia. From the same 
section draw the spherical embryonic female gametophyte. 

8. Draw a female gametophyte showing archegonia (ovaries) _with ospheres. 

9. Draw an archegonium (ovary) in which the nucleus of the oosphere has 
divided into four nuclei. 



10. Draw the upper part of a female gametophyte, showing remains of arche- 
gonia with an elongated cavity below them in which appear a number of embryos 
in various stages of development. Only one of these embryos survives, probably 
the one which has a slight advantage in size, vigor, and food supply. Note the 
struggle for existence which must go on among these embryos. 

11. Sketch a mature seed, showing the wing. Let a winged seed drop to 
the floor from a height of six or seven feet and note how it falls. Describe the 
adaptation this seed has for dissemination. Note also the readiness with which 
the seed is separated from the wing. Of what use is this adaptation? 

Fig. 14. — Life Cycle of Pine. 

(g) Seedlings and Primitive Leaf Arrangement. 

Plant seeds of Pinus and Thuja accidentalis and use fresh plantlets or pre- 
serve in alcohol. Also obtain branches of the common juniper (Juniperus com- 
munis L. Family, Juniperacese) and cultivated varieties of Thuja known as 
retinispora forms. In these retinispora or juvenile forms, branches often change 
suddenly from the form with spreading leaves to the flattened condition, and the 
flattened branches again revert to the form with spreading leaves. 

1. Sketch a pine seedling which has sprouted, showing the seed coat still 
covering the cotyledons. Sketch a seedling with cotyledons expanded. Describe 
the important changes which take place in the embryo during the process of 

2. Sketch a branch of Juniperus communis and note that all of the leaves 
are of the spreading type. 

3. Study and sketch the seedings of Thuja occidentalis and note that at first 
the leaves are of the spreading type much like those of Juniperus, and that later 
the branches have the flattened form characteristic of the adult plant. Apply 
the recapitulation theory as given in connection with the moss protonema. From 


this it would appear that the ancestors of Thuja had the leaves arranged like 
those of the common juniper. 

4. Study and draw a small branch of Thuja (retinispora form), in which 
the upper part of a flattened branch has changed back to the juvenile form. In 
such cases there is a second reversion. In other words, the branch takes on 
first one form and then another successively. 

5. Make a diagram showing the life cycle of a pine. See Fig. 14. 

6. 'Note on the development of the carpellate pine cone. 

The young carpellate cones of Pinus laricio begin to develop in the bud 
during the summer or fall, and in the following spring the carpels have young 
ovules with a distinct integument. Later (about the middle of May) the ovules 
are pollinated and the megaspore is developed. In the following autumn (Octo- 
ber) the megaspore has germinated and the female gametophyte is developing as 
a hollow spherical body composed of free, naked cells. It passes the winter in 
this condition. In June of the following year the archegonia with eggs are ready 
for fertilization and the pollen-tubes have grown down thru the nucellus. About 
the last week in June or the first in July fertilization occurs, and the embryo is 
matured and in the resting condition in the following autumn. The seed is usually 
shed late in the winter or in the early spring of the year following. The whole 
history thus covers nearly three full years. 

LXXIV. Taxus canadensis Marsh. American Yew. 

Phylum, Strobilophyta. Class, Coniferae. Order, Taxales. Family, Taxaceae. 

The yew is a low shrub growing on moist banks and hills, especially in the 
shade of large conifers. It is common northward. Herbarium and alcoholic 
material may be used if fresh branches are not available. 

1. Sketch a branch, showing arrangement of leaves. Describe. 

2. Under dissecting microscope draw a staminate cone. How are the stamens 

3. Draw a single stamen under low power and note the peltate form. How 
many microsporangia? Compare the shape of this stamen with the sporophyll of 

4. Under dissecting microscope draw a small fertile branch with a young 
ovule at the tip. 

5. Cut longitudinal sections of the branch with ovule, mount, and draw 
under low power, showing the megasporangium in the center surrounded by the 
long inner integument and a short outer undeveloped aril, with scale-leaves on 
the stem below. 

6. Draw a ripe seed with the thick, fleshy, red aril. Compare the aril with 
the ovuliferous scale of Pinus. 

LXXV. Higher Gymnosperms. 

Phylum, Strobilophyta. Class, Gneteae. 
Study herbarium specimens. 

1. Make a sketch of a small plant of Ephedra Sp. (Order, Ephedrales. 
Family, Ephedraceae). Note the slender green stems and the dry scale-leaves. 
In what ways is this plant adapted to a xerophytic environment? 

2. Make a sketch of a branch of Gnetum gncmon L. (Order, Gnetales. 
Family, Gnetceae).. Note the large broad leaves. This is a tropical tree cul- 
tivated in India and surrounding regions. 





Along with this series of outlines on the Anthophyta, the student should be 
given work in identification with a key and several periods can profitably be spent 
in analyzing and making diagrams of various spring flowers. 

LXXVI. Magnolia sp. Magnolia. Phylum, Anthophyta. Class, Dicotylse. 
Order, Ranales. Family, Magnoliacese. 

The magnolias are among the most primitive of the Anthophytes. Any of 
the native or cultivated species will have suitable flowers in early spring. They 
may be used fresh or preserved in alcohol. 


1. Sketch the entire flower; describe size, color, etc. Note the character of 
the stem. Compare the flower with the cones of Lycopodium, Selaginella, and 

2. Sketch a sepal, a petal, a stamen and a carpel; describe each organ. The 
stamen is a microsporophyll and the carpel a megasporophyll. 

3. How many sepals in the calyx? How many petals in the corolla? How 
many stamens in the andrecium (stamen set) ? How many carpels in the gyne- 
cium (carpel set)? How many cycles in the perianth? Note especially that the 
stamens and carpels are arranged spirally. Compare several flowers as to the 
constancy or variability in number of parts. Make a diagram of the flower. See 
Fig. 16a. 

LXXVII. (a) Sagittaria latifolia Willd. Arrow-head. 

Phylum, Anthophyta. Class, Monoctylae. Order, Alismales. Family, Alis- 

The broad-leaf arrow-head grows in moist ground on the margin of ponds, 
creeks and canals and blooms in summer. If fresh material is not available, 
good herbarium specimens may be used. Flowers and other parts may also be 
preserved in alcohol. 


1. Sketch and describe the entire plant, noting the character of the leaves, 
stem, roots, and inflorescence. 

2. Sketch the staminate flower, showing sepals, petals and stamens. How 
many parts in each set? Find the vestigial carpels. Draw one under dissecting 

3. Sketch the carpellate flower and describe the parts present. What parts 
of the two flowers are cyclic and what parts spiral in arrangement? Is this 
sporophyte monecious or diecious? 

4. Under dissecting microscope draw a sepal, a petal, a stamen (microsporo- 
phyll) and a carpel (megasporophyll). Compare the normal carpel with a ves- 
tigial carpel. How did this plant attain the monecious condition? 

5. Cut cross sections of a young stamen, mount, and draw under low power. 
How many microsporangia? Note that the stamen is made up of anther and 

6. Cut off one side of a carpel so as to expose the ovule (megasporangium). 
Draw under low power, showing the stigma, short style, and ovulary. Note 


that the stigma is a new organ not present in any of the Gymnosperms. Why is 
the stigma necessary to this carpel? 

(b) Ranunculus abortivus L. Crowfoot. 

Phylum, Anthophyta. Class, Dicotylse. Order, Ranales. Family, Ranuncu- 

This plant is common in April and May along brooks, on hillsides, in 
meadows, and along roads. 


1. Sketch the entire plant, showing the various organs. 

2. Sketch the flower and describe the condition of the four sets of floral 
organs. Note that the flower is bisporangiate. Compare with the cone of Sela- 

3. Draw a sepal, a petal, a stamen, and a carpel under dissecting microscope. 

LXXVIII. Alisma subcordatum Raf. Water Plantain. 

Class Monocotylse. Order, Alismales. Family Alismaceae. 

The water plantain is common in wet and muddy places, on the margin of 
ponds and creeks and blooms in summer. Herbarium specimens and preserved 
material may be used. 


1. Sketch a leaf and a part of the inflorescence. 

2. Sketch a flower showing the four sets of floral organs — calyx, corolla, 
andrecium and gynecium. How many sepals, petals, stamens and carpels? Are 
the parts spiral or cyclic? Free or united? Is the flower monosporangiate or 
bisporangiate? Note that the flower is hypogynous. What advance does this 
flower show over that of Sagittaria or Ranunculus? 

3. Make a diagram of the flower. See Fig. 16b. 

4. Cut cross sections of the stamens or use prepared slides and draw under 
low power. How many microsporangia (pollen-sacs) ? Cut open the ovulary and 
dissect out the ovule (megasporangium). Draw. 

5. From prepared slides draw a microsporocyte and a microspore, showing 
the nucleus, cytoplasm and wall. 

6. From prepared slide draw a young ovule, showing the funiculus, the integ- 
uments, the megasporangium proper (nucellus), and the single megaspore. Note 
the absence of a wall around the megaspore. Why not present? 


7. From prepared slide draw a male gametophyte (pollen-grain), showing 
the tube nucleus and the two elongated sperm cells. 

8. From prepared slide draw an eight-celled female gametophyte (embryo- 
sac), showing the three anipodal cells, the two polar nuclei, the oosphere, and 
the two synergids. The oosphere and the two synergids are called the egg- 
apparats (ovary). 

9. From prepared slide draw a mature, seven-celled female gametophyte, 
showing the fertilization of the egg and the conjugation of the polar cells to 
form the definitive cell. Look for the conjugation of the second sperm with the 
polars (triple fusion). 

10. From a prepared slide draw an embryo-sac with endosperm cells, which 
have come from the division of the definitive cell, and with young embryo, con- 
sisting of the embryo proper, the suspensor cells and the large, vesicular, basal, 



suspensor cell. Note that the conjugation of the polar cells and the subsequent 
development of the endosperm are entirely new phenomena, nothing similar being 
known in plants below the anthophyta. In many other anthophyta the second 
sperm cell from the pollen-tube comes down and unites with the polar cells pro- 
ducing a triple fusion, as in Alisma. 

11. Carefully remove a mature embryo from the seed and sketch under low 
power, showing the single cotyledon, the lateral plumule and the radicle. 

Fig. 15. --Life Cycle of Angiosperm (Alisma.) 

12. Note that in this plant the seed remains in the ovulary, i. e. the fruit 
is indehiscent. Make a diagram showing position of the carpel wall, the integu- 
ments of the ovule, the endosperm and the embryo. Note also that the ovule is 
iirst orthotropous, then anatropous and finally campyllotropous. 

13. Sketch a young seedling. 

14. Make a diagram in the notes showing the general life cycle of an 
.angiosperm. See Fig. 15. 

LXXIX. Sedum acre L. Wall-pepper. 

Class, Dicotyke. Order, Saxifragales. Family, Crassulacese. 
Many of the sedums grow well in greenhouses and in window gardens. They 
usually bloom abundantly in the spring and the above or any other species will be 
found suitable. 

1. Make a careful drawing of the flower and describe the character of the 
different parts. 

"2. Make drawings of the calyx, the corolla, the andrecium and the gynecium. 
3. Answer the following questions correctly : 

Is the flower hypogynous, perigynous, or epigynous? 

Is it tetracyclic or pentacyclic? 

Are the circles or whorls trimerous, tetramerous or pentamerous? 



Are the organs of any whorl or set united or partly united? 
Is the flower isocarpic or anisocarpic? 

Is it actinomorphic, isobilateral, zygorhorphic, or unsymmetrical? 
4. Make two diagrams showing the true condition of the flower as learned 
above. See Fig. 16 c and d. 

LXXX. Trillium grandiflorum (Mx.). Large-flowered Trillium. 
Class, Monocotybe. Order, Liliales. Family, Liliacese. 

The large flowered Trillium grows in rich woods and blooms in April and 

1. Make a sketch of the entire plant, showing the flower, leaves, and short 
tuberous rhizome with contractile roots below. How deep was the rhizome under 
ground? Describe how it descends into the earth. This plant is a geophilous, 
herbaceous perennial. What are the advantages of the geophilous habit? 

2. Cut a cross section of the compound ovulary, mount, and draw under low 
power, showing the cavities with ovules. 

3. Describe the condition of the flower according to the questions asked 
under Sedum acre. Make a diagram of the flower. See Fig. 16e. 

LXXXI. Cypripedium parviflorum Salisb. Yellow Lady's-slipper. 
Class, Monoc'otylae. Order, Orchidales Family, Orchidacese. 
This lady's-slipper grows in wet places and low woods, and blooms in May 
and June. Any other species will do as well. 

1. Sketch part of a plant, showing the flower and part of the leafly stem. 

8888 Lft Hti -4l * # JT; I -a jo 

.,>hKxJ a\ t /J V % TO 

%^ kZ^J 

Fig. 16. — Diagrams of Flowers. 

2. Cut cross sections of the ovulary, mount and draw. How many carpels? 
Study the flower with the aid of the diagram, Fig. 16 f. 


3. Copy the diagram in the notes and write a general description of the 
flower, noting especially that it is organized on the same plan as the Trillium 
flower, that some of the parts have disappeared, that it is epigynous and zygo- 
morphic, that certain parts are united, and that it is highly specialized for insect 

4. Why should this flower be placed higher than any of the monocotyls pre- 
viously studied? Make a comparison of the flower of Sagittaria, Alisma, Trillium 
and Cypripedium. 

LXXXII. Catalpa speciosa Warder. Hardy Catalpa. 

Class, Dicotylse. Order, Scrophulariales. Family, Bignoniaceae. 

The Catalpa is cultivated extensively and blooms abundantly in May and June. 

1. Study the large compound panicle and draw a single flower. 

2. Describe the flower carefully, noting the condition of each floral set and 
whether the flower is hypogynous or epigynous, whether actinomorphic or zygo- 
morphic. What adaptations for insect pollination? Note especially the rudi- 
mentary or vestigial stamens. Be careful to distinguish vestigial organs (vestiges) 
from incipient organs (incepts) and from nascent organs. 

3. Cut cross sections of the ovulary,, mount, and draw. How many carpels 
in the gynecium? 

4. Make two diagrams of the flower, showing transverse and longitudinal 

LXXXIII. Cornus femina Mill. Panicled Dogwood. 

Class, Dicotylse. Order, Umbellales. Family, Cornacese. 

This common shrub usually forms thickets, in forests and on hillsides. It 
blooms in June, producing an abundance of flowers. Any other species with 
panicled flowers will do. 

1. Sketch the entire infloresence and note the arrangement of the numerous 
small flowers. 

2. Under dissecting microscope draw a single flower. How many cycles? 
How many stamens, petals and sepals? Note the minute size of the calyx. 

3. Cut cross section of the ovulary. Draw under low power. How many 
carpels? Note that the flower is epigynous. 

4. Compare this inflorescence with that of the flowering dogwood, Cynoxylon 
floridum (L.) noting especially the origin and nature of the white involucre. 

5. Make a transverse and a longitudinal diagram of the flower. See Fig. 
16 g and h. 

LXXXIV. Ageratum conyzoides L. Ageratum. 

Class, Dicotylse. Order, Compositales. Family, Helianthaceae. 

Ageratums are annuals which bloom all summer and are much used for 
borders. The flowers may be had in the greenhouse at any time of the year. The 
plants will live and bloom for a long time. 

1. Sketch one of the heads under dissecting microscope, showing the bracts 
of the involucre and the numerous small tubular flowers. 

2. Under dissecting microscope draw a single flower. What is the condition 
of the pappus? What does the pappus represent? 

3. Dissect the flower and draw the corolla and andrecium and the gynecium 
under dissecting microscope or low power. Describe the flower and its parts in 


LXXXV. Chrysanthemum leucanthemum L. Ox-eye Daisy. 

Order, Compositales. Family, Helianthaceae. 

This plant grows in fields and meadows and blooms in May and June. 
- 1. Draw one of the heads, showing the bracts of the involucre, the Ungulate 
or ray flowers and the tubular or disk flowers. 

2. Under dissecting microscope draw a ray flower and a disk flower. Describe 
each. What is the condition of the calyx? Why should the outer flowers develop 
as ray flowers rather than the inner ones? Note that the ray flower is zygomor- 

LXXXVI. Leontodon taraxacum L. Dandelion. 

Order, Compositales. Family, Cichoriaceae. 

The dandelion blooms from early spring to late autumn, so plants may usually 
be obtained without difficulty. 

1. Sketch an entrie plant, showing root, short stem, rosette of leaves, and 
slender stems bearing heads of flowers. Note that the dandelion is geophilous. 
Why does it not grow up out of the ground? How do you account for the rosette 
habit? Remember that the lowest seed plants were trees. This is one of several 
culmination types. 

2. Make a sketch of a single head. Note that all the flowers are ligulate. 
Also note that the embryonic corollas are tubular, showing five teeth on the limb, 
and only become strap-shaped when they expand. Make a series of sketches show- 
ing this. How does this indicate that Leontodon is a higher type of development 
or specialization than Chrysanthemum leucanthemum ? 

3. Under dissecting microscope draw a single flower. Describe the pappus, 
corolla, andrecium, and gynecium. 

4. Draw some of the ripe furit. 'Note adaption for suspension in the air. 
Of what special advantage is this parachute arrangement? Note the action of 
the involucre while the fruit is ripening. This extraordinary parachute is an ex- 
ample of overadaptation. 

5. How many seeds are in each dandelion fruit? i. e., how many for each 
flower? How many seeds are produced on an average-sized head? About how 
many heads of flowers are matured from a fair-sized dandelion plant in one sea- 

6. Suppose that you had but one mature dandelion plant and that it produced 
seed normally for ten years and that each seed developed into a mature plant and 
began to reproduce at the average rate the second year, (i. e., when two years old) 
how many offspring would there be at the end of ten years? 

7. The total land surface of the earth is about fifty-three millions of square 
miles, how many dandelion plants would there be for each square mile of land 
surface at the end of ten years? 

8. Note. — The above problems will indicate to some extent the great possi- 
bilities of reproduction present in many plants. It will be remembered that each 
seed contains a little, dormant embryo; therefore, every seed that perishes means 
the destruction of a young plant. It is evident that a very large per cent, of young 
plants must perish each year, and that those which survive for any length of time 
must usually undergo a severe struggle for existence. In this struggle for life and 
place the fittest usually survive; i. e., those which are able to grow more vigorously 
and thus crowd out thei- weaker neighbors and those which are best adapted to 
their environment. 



LXXXVII. Triticum aestivum L. Wheat. (T. vulgare). 

Phylum, Anthophyta. Class, Monocotylse. Order, Graminales. Family, Gram- 

Material should be collected during and after the flowering period in May and 
June, and dried or preserved in 70 per cent, alcohol. 

1. Study and sketch the spike (head) and describe. Note the character of the 
stem. What mechanical advantage in the disposition of the tissues of the stem? 
The axis of the spike is called the rachis. 

2. Draw a single spikelet, noting the two empty glumes at the base, and 
several flowers. How many flowers? What is the condition of the uppermost 
flowers of the spikelet? The axis of the spikelet is called the rachilla. 

3. Draw the two empty glumes noting their peculiarities. 

4. Dissect a single flower. It is inclosed in two glumes, the flowering glumes ; 
the one with the awn is the lemma, and the inner one is the palet. Draw both and 

5. Just inside of the lemma at the base of the gynecium are minute scales 
called lodicules. How many? Draw one under low power. What might they 

6. There are three stamens in the andrecium, and the gynecium develops into 
a single grain. Make a diagram showing the positions of the empty glumes, the 
lemma and palet, the lodicules, the stamens, the ovulary, and the axes of the spike 
and spikelet. 

LXXXVIII. Fuchsia sp. Fuchsia. 

Class, Dicotylse. Order, Myrtales. Family, Onagracese. 

Fuschias are commonly cultivated in greenhouses and as house plants. The 
flowers should be studied fresh and any of the common greenhouse species will do. 

1. Study and draw the flower. 

2. Draw the gynecium with style and stigmas. Cut cross sections of the 
ovulary, noting the number of cavities and ovules. 

3. Draw the perianth tube or hypanthium split open, showing the calyx, 
corolla, and andrecium. How are these parts grown together? Note the color of 
the calyx and the corolla. 

4. Why does the epigynous condition and the peculiar development of the 
hypanthium indicate a high type of floral development? Describe the entire 

5. Make transverse and longitudinal diagrams of the flower, showing the 
relationships of the parts. 

LXXXIX. Populus deltoides Marsh. Cottonwood. 

Phylum, Anthophyta. Class, Dicotylae. Order, Salicales. Family, Salicaceae. 

This is a large tree of rapid growth, common on flood-plains of rivers, and 
is much planted for ornament. It blooms in April. 

1. Collect staminate and carpellate catkins or aments, noting that the trees 
are diecious — some are staminate trees and some carpellate trees. Note the differ- 
ence in color between the two kinds of flowers. How do you explain the differ- 
ence? Draw the two catkins. 


2. Draw a single staminate flower and a carpellate flower and describe. Any 
perianth? Why are the stamens red and not yellow as is commonly the case? 
Why is it incorrect to say male tree instead of staminate tree and female tree 
instead of carpellate tree? Or why should you not say male flower and female 

3. When the capsules ripen study the seed. How is it distributed? How 
effective is this method? Why should only staminate trees be planted in a city? 
How would you make sure that you had staminate trees to plant?' Could you 
plant cuttings ? This tree endures city conditions quite well. 

4. iNote the different kinds of scars on the tree: leaf scars, stipular scars 
bundle-scars, self-pruning scars, lenticels. Note also that the pith is 5-angled. Is 
there anything on the outside of th twig corresponding to this? 

5. Note that the leaves have a strong tendency to take a vertical position 
especially on twigs that grow erect. Draw and describe the flattened condition of 
the petiole by which this is accomplished. Why are the two sides of the leaf 
nearly alike? What advantage in the vertical position? Why do you hear a 
musical rustle of the leaves when the wind is blowing? Note the two glands at 
the base of the blade. Of what use are the glands? 

6. Study and draw self-pruned branches. Fresh material can be obtained in 
summer and autumn and preserved in alcohol but the dry twigs will do fairly well. 
Notice that the winter buds are in perfect condition. Draw the base showing the 
surface of the scar. Draw a self-pruning scar that has healed over. How is the 
cleavage plane produced in the basal joint? Why are the branches pruned off? 
How old are the branches when self-pruned? 

7. Note. This outlin may be used as a special exercise to be worked up 
during the term. A special paper may be written on the subject including the 
above and many other interesting points connected with the life of this tree. 

XC. Polemonium reptans L. Greek Valerian. 
Class, Dicotylae. Order, Polemoniales. Family, Polemoniacese. 
This is a perennial herb growing in woods. It blooms in April and May. 
Fresh material must be used. 

1. Describe the entire plant and sketch a branch showing the leaves and 
flowers. If young plants are available, note the circinate vernation. 

2. Study a single flower. Note the blue color. Is blue a common color of 
flowers? Note the character of the calyx, the corolla, the andrecium, and the 
gynecium, and draw and describe each set. 

3. Cut cross sections of the ovulary and draw. How many cavities? How 
many ovules in each cavity? 

4. If ripe capsules are present wet the seeds on the slide and examine care- 
fully under low power. What peculiarity becomes evident after a few moments? 
Crush or break up the seed with a scalpel and observe further. 

5. Make a diagram of the flower. 

XCI. Comparison of Carpels. 

1. If not previously studied, draw a carpel of Cycas revoluta L. 

2. Draw a carpel of the Kentucky coffee-bean {Gymnocladus dioica (L.).) 

3. ketch a nearly mature fruit of the Velvetleaf (Abiitilon abutilon (L.).) 
Separate the ovularies and draw a single carpel. 


4. Carefully separate the ovularies of the carpels of an orange (Citrus auran- 
tiuvi L.) so they will lie side by side in a row. Draw. Note that some of 
the divisions are smaller than the normal. There is a struggle for existence among 
the members of the gynecium so that some are not fully developd. 

5. Make a comparison of the four fruits studied above. 

XCII. Dicotyl Seed. 

Study the fruit and seed of the Olive (Olea europaea L.). Use either fresh 
or pickled olives. The samara of Fraxinus is also satisfactory. 

1. Sketch the entire drupe. Xote that the pericarp consists of a fleshy exocarp 
and a thick, stony endocarp. 

2. Break the endocarp and remove the fleshy seed within. Remove the mem- 
branous seed coats and sketch the fleshy kernel inside. This is the endosperm. 

3. Remove the embryo and draw, showing the short radicle, the two cotyle- 
dons, and the plumule. Compare the kernel of Olea with that of the Pine seed 
and note the differences. 

XCIII. Section of Leaf. 

(a) 1. Cut cross sections of the lamina of a sunflower (Helidnthus dnnuus 
L.) leaf fresh or preserved in alcohol, mount, and study under low and high 

2. Draw and describe, showing the following tissues : upper epidermis with 
thick cuticle and multicellular hairs, palisade parenchyma, spongy parenclryma with 
large intercellular spaces, sections of vascular bundles, and lower epidermis with 
stomata and multicellular hairs. 

3. How do you account for the palisade arrangement of the cells in the 
upper part of the leaf ? 

(b) Cut sections of Beech Leaves or use prepared slides. Draw and com- 
pare the tissues with those in the sunflower leaf. 

XCIV. Leaf Variation. 

1. Obtain a series of fresh or pressed leaves of the red mulberry (Mdrus 
rubra L.) or of the giant ragweed (Ambrosia trifida L.) and make outline sketches 
of ten different forms. 

XCV. Section of Winter Bud. 

1. From alcoholic material cut longitundinal sections of common lilac buds 
(Syringa vulgaris L.) Mount and sketch under low power. Note the flat apex 
with outer dermatogen and hypodermal meristematic tissue; and a little farther 
down the epidermis, cortex (periblem), procambium (formative tissue of vascular 
bundles), and the central pith. 

2. Note the origin of the leaves, beginning at the apex, and also the origin 
of the lateral buds in the axils of the leaves. Make a sketch showing the entire 
upper part of the bud, with all the structures mentioned above. 

XCVI. Monocotyl Stem. 

1. Cut cross sections of young corn stems preserved in alcohol, stain and 
mount; or use prepared slides. Sketch the entire section under dissecting micro- 
scope, showing epidermis, band of sclerenchyma, large pith or ground tissue, and 
the scattered vascular bundles. 


2. Under high power draw one of the bundles. Note the large vessels 
situated in the xyiem arranged like a letter V, the cavity in the tissue at the apex 
of the V, the bundle of phloem between and beyond the two large vessels, and 
the sheath of sclerenchyma about the bundle. 

XCVII. Herbaceous Dicotyl Stem. 

(a) Sunflower Stem. 

1. Cut cross sections of a young sunflower stem preserved in alcohol, mount 
and stain ; or study prepared slides. 

2. Sketch the entire section under dissecting microscope, showing cortex, 
circle of vascular bundles, and large central pith. This vascular system is an 
example of a siphonostele. Compare with Botrychium. 

3. Under low power draw part of a section showing the epidermis with 
epidermal hairs, the layer of collenchyma immediately below this, the parenchyma 
with resin passages, the vascular bundles with cambium layer, the medullary rays, 
and the central pith. 

4. Under high power draw a single vascular bundle, selecting one of the 
narrow, oval type. Represent in order the external bundle of sclerenchyma, the 
phloem, the cambium, and the xylem usually in a double layer. 

5. Notice the mechanical principles involved in the structure of the stem and 
the vascular bundle. Compare with a T railroad rail. 

(b) Pumpkin Stem. 

1. Cut cross and longitudinal sections of the stem of Cucurbita pepo L., stain 
and mount, or study prepared slides. Sketch the cross section under dissecting 
microscope. iNote the epidermis, the cortex, the vascular bundles, the pith, and 
the large central cavity. 

2. Under high power study the longitudinal sections and draw sieve-tubes 
showing the sieve-plates in the phloem. 

3. In the xylem find and draw one of the large reticulate wood vessels; also 
a spiral wood vessel with a single spiral thickening and one with two spirals ; also 
draw an annular wood vessel in which the thickenings are in the form of rings. 

XCVII I. Dicotyl Woody Stem. 

1. Cut cross sections of a very young twig of the beech (Fagus grandifdlia 
Ehrh.) and one a year old, preserved in alcohol, stain and mount, or use prepared 
slides. Under low power note the cortical layer, the circle of vascular bundles 
with medullary rays between, and the central pith. Draw. This is a siphonostele. 
Compare the younger section with the sunflower. Under high power draw a nar- 
row sector passing thru a vascular bundle, showing epidermis, cork (periderm), 
cork cambium Qphellogen), seoond/ary cortex (phelloderm), primary cortex, 
sclerenchyma, phloem, stelar cambium, xylem (wood), and pith. Draw a single 
complete bundle,' showing the sclerenchyma, the phloem, the cambium and the 

2. Cut cross sections of twigs of the White Ash (Frdxinus americana L.), 
preserved in alcohol, one very young, one a few months old, one a year old and 
one two years old. Study and draw the young sections noting the epidemis, cortex, 
vascular bundles and pith. Study the one and two year old sections and note the 
formation of the cork and the secondary development of phloem and xylem. 
Draw and describe. 


3. Cut cross sections of linden twigs (Tilia sp.) preserved in alcohol. Take 
one very young branch, one a year old, one two years old, and one three years 
old. Mount and stain; or use prepared slides. Study under low and under 
high power. Draw the year old section, noting the following structures : epidermis, 
cork layer, cortex, phloem and sclerenchyma layer (inner bark), stelar cambium, 
xylem (wood) with medullary rays, and pith. 

4. Make a series of diagrams showing the primary structure and how the 
secondary structures are developed for the first three years. 

5. Under high power draw a small area of the xylem showing a medullary 
ray, large empty pitted vessel, small empty wood fibers, narrow empty tracheids, 
and protoplasmic wood parenchyma. Draw also a small area of cells from the 
bark, showing a medullary ray, light-colored thin-walled sieve tubes, very thick- 
walled bast fibers with only a minute lumen, protoplasmic companion cells in and 
around the sieve tube tissue, and large protoplasmic bast parenchyma. 

6. Cut cross sections of a very young and of a year old twig of cottonwood 
(Populus dcltdidcs Marsh.); mount and stain. 'Note the following structures: 
epidermis, periderm (cork layer) and the five corky ridges, phellogen (cork cam- 
bium), phelloderm (secondary cortex), primary cortex, sclerenchyma (fiber bun- 
dles), phloem with a narrow band of sclerenchyma, stelar cambium, xylem (wood), 
.and the five angled central pith. 

7. Make a sketch of a cross section of a polished tree trunk of black walnut 
{Juglans nigra L.), showing these struc cures : pith, heartwood (duramen), sap- 
wood (alburnum), annual rings with early and late wood, medullary rays, the 
stelar cambium and phloem (inner bark) separated by irregular strips or areas 
or corky tissue from the outer bark. The outer bark has been developed from 
the cortex and phloem and modified by successive layers of cork cambiums 
(phellogen). These irregular strips of corky tissue can easily be seen in the 
outer bark with the naked eye. 

8. Compare with the walnut a polished section of the trunk of a bur oak 
{Quercus macrocarpa Mx.) In this the medullary rays are much more prominent. 

9. Study cross section of the trunk of Catalpa speciosa Warder. Measure 
the width of the annual rings and draw a curve showing the growth in diameter 
for the entire life of the tree trunk from which the section was taken. 

XCIX. The Root. 

(a) Section of Buckeye Root. 

1. Cut cross sections of one of the larger fleshy rootlets of Aesculus sp. 
(preserved in alcohol). Mount and draw under low power, representing the fol- 
lowing structures: the four or more primary xylem bundles, four or more primary 
phloem bundles alternating with the xylem, the beginning of the stelar cambium 
passing between the xylem and phloem, the endodermis or bundle sheath, and the 
broad cortex, with a superficial layer of cells known as the piliferous layer. 

2. Cut cross sections of a somewhat older root which has turned brown, 
mount, and sketch the entire section under low power. Represent the following 
structures : the central strand of xylem composed of wood vessels and smaller 

• cells, the stelar cambium, the band of phloem consisting of several kinds of cells, 
.the remains of the endodermis, and the cortex and piliferous layer turned brown. 


(b) Embryonic Root Tip. 

1. Carefully remove the hard parts around the base of the embryo in a grain' 
of corn (Zea mays L.) and with a razor cut longitudinal sections of the radicle 
of the dormant embryo. The corn may be soaked in water for a while before 
cuting the sections, tho this is not necessary. 

2. Mount the central sections in water and sketch under low power.. Note 
the following embryonic tissues : the outer scutellum, the root-sheath of a dark 
appearance inside of the scutellum, and the root tip inside of the root-sheath. The 
root tip is made up of the root-cap (of a light color), the dermatogen (a layer of 
large cells inside of the cap), the dark layer of periblem, the central light plerome,. 
and the growing point at the tip of the plerome. Below the dermatogen, at the 
apex of the root is the formative tissue of the root-cap, known as the calyp- 
trogen. It will probably not be distinct enough in these sections to trace out, but 
its position should be noted. 

(c) Root Hairs. 

1. Sprout grains of corn on moist blotting paper in a box or under a bell- 
jar; after a few days the roots will be covered with root hairs. Sketch under 
dissecting microscope. 

2. With a scalpel cut off some of the epidermis containing root hairs, mount 
and examine under high power. Draw and describe. 

3. Under low power examine roots of young seedlings planted in soil and 
note the relation of the root hairs to the soil particles. 

C. Lenticels. 

1. Examine and sketch the bark of a green and of a year-old elder stem 
Sambucus canadensis L. showing the surface covered with lenticels. 

2. Cut cross sections of the bark, mount, and examine under low power. 
Sketch one of the lenticels. How and where do they originate? 

CI. Starch, Cellulose, Lignin, tannin, etc. 

1. Cut a potato and scrape off some of the cells. Mount in water and study 
under high power. Draw some of the large starch grains present, showing the 
hilum and the stratified structure. 

2. Place a drop of iodin solution beside the cover-glass and watch its effect 
on the starch. What is the color reaction? 

3. Mount some wheat flower in water and treat with iodin. Note the blue 
colored starch and the yellow colored proteid material. 

4. Mount a hair of common cotton (Gossypium herbdceum L.) It is made 
up of nearly pure cellulose except the small central cavity in which is a small 
amount of dry protoplasm. Draw. Treat with Schulze's solution (Chlor-zinc- 
iodin) and after a while note the color reaction. Care must be taken so as not to 
get any of this solution on the microscope as it is strongly acid. 

5. Treat cross sections of a sunflower stem (from alcoholic material) with 
Schulze's solution, examine, and note the cellulose reaction in the walls of the 
cortical and pith cells. 

6. Treat a section of a sunflower stem with phloroglucin, mount and study 
color reaction in the xylem bundle. Care must be taken in its use as it contains 
an acid. 

7. Cut cross sections of a young twig of linden preserved in alcohol, treat 
with phloroglucin, mount, and note color reaction in the wood. 


8. Cut cross and tangential sections of peach pits taken just when they are 
beginning to harden. Mount and study the cells of this stony tissue. Draw a 
number of the cells and describe. 

9. Tannin, which is the cause of astringency of many fruits, may be readily 
demonstrated by Vinson's method. Pour some sweet spirits of nitre, or a 20 
per cent, alcoholic solution of nitrous ether, into a glass stoppered jar containing 
broken pieces of pottery or glass to prevent the fruit to be treated from falling 
into the liquid, and then drop in some fruit rich in tannin like green dates or 
persimmons. Stopper tightly and let remain from 12-24 hours. At the end of 
that period the tannin bearing cells will be of a dark brown color and will show 
distinctly when the fruit is cut open. Mount some of the dark cells in water 
and examine under low and high power. Note the large tannin masses. Crush 
the masses by pressing on the cover-glass and note how they stretch and finally 
break. A stained fruit may be preserved in 95 per cent, alcohol. Date fruits 
are ideal for this experiment and may be obtained in autumn from Arizona. 

10. Aleurone grains. Cut sections of the endosperm of a seed of Ricinus 
communis L., castor-oil plant, after soaking in water. Mount in alcohol or 
dilute glycerin and draw several cells showing the oval aleurone grains. Each 
grain usually has a crystalloid and a globoid in its interior. 

CII. Crystals. 

The material for sectioning may be preserved in alcohol. 

1. Cut cross sections of the rhizome of the large blue-flag (Iris versicolor L.) 
mount, and under high power draw the simple crystals present. 

2. Cut sections of a year old twig of the wahoo (Eudnymus atropurpureus 
Jacq.), mount, and draw the large compound sphere-crystals in the pith and 

3. Cut sections of the rhizome of the lily-of-the-valley (Convalldria majalis 
L.), mount, and draw the bundles of the needle-shaped crystals, raphides. 

4. Cut cross sections of the leaves of the India-rubber fig. (Ficus eldstica 
Roxb.) mount and draw the large cystoliths which are amorphous masses of 
mineral substance suspended from a pedicel. The mineral substance of the cysto- 
lith is mainly calcium carbonate. 

OIL Lipochrome. 

1. Cut thin sections of the rind of an orange, mount in water, and examine 
under high power. Draw a cell showing the chromoplasts. 

2. Cut sections of the root of the common cultivated carrot (Daucus carbta 
L.). Mount and draw a cell showing the color bodies. 

3. Mount pieces of the yellow corolla of the squaw weed (Senecio aureus L.) 
or any other yellow flower, examine under high power and draw a cell with 
chromoplasts. Describe the cause of the yellow color in these tissues. 

CIV. Anthocyan. 

1. Cut sections of the root of the red garden beet (Beta vulgaris L.), mount, 
and examine under high power. Note that the red coloring matter is in the 
cell sap. 

2. Cut sections of any leaf with red color as the red leaved coleus (Cdleus 
blumei Benth.), mount, and study the color under high power. 

3. Cut off some of the epidermis of a red apple (Mains mains (L.),) mount, 
and studv the cause of the color. 


4. Mount part of a petal of a red greenhouse Pelargonium. Study the red 
coloring matter in the cells. 

5. Mount part of a petal of a blue flower like Salvia pitcheri Torr. or Viola 
odordta L.) and study the nature of the color. 

CV. Solution of Anthocyan. 

1. Take a quantity of the corollas of Maurdndia barclaidna Lindl. (a com- 
mon greenhouse vine) or flowers of Tradescantia virginica L., place them in a 
dish and after crushing them cover with a quantity of 95 per cent, alcohol. After 
a few days or so pour off the alcohol into a bottle and preserve. 

2. Take a test-tube about one-third full of the alcohol and add a few drops 
of aqua ammonia. Note color reaction. Neutralize with hydrochloric acid until 
the liquid is again clear. Continue to add acid drop by drop. What is the color? 

3. Place some red pelargonium (greenhouse geranium) flowers directly in 
ammonia water. Note that they change to blue. Transfer to acid alcohol and 
note that they change back to red. 

4. How do you account for the change of color in many flowers during the 
period of blooming and for the many varieties of color produced by cultivation as 
in the common morning-glory {Ipomoca purpurea (L.) ? 

CVI. Temperature Test with Anthocyan. 

1. Take two good thermometers which register alike, wrap the bulb of one 
in a red begonia leaf and the other in a green begonia leaf, put each in a tumbler 
and place for some time in direct sunlight. Note the difference in temperature. 
Place the tumbler's with thermometers in diffuse light and note the temperature 
again. Place them in a dark box and after a while read the temperature. Make 
a second test in the sunlight. 

2. Describe one of the uses of anthocyan in roots, stems, leaves, flowers and 

CVI I. Chlorophyll Solution. 

1. Take a quantity of green leaves, such as the blue grass or greenhouse 
pelargonium; place them in a porcelain mortar or other suitable dish; cover with 
95 per cent, alcohol; and crush the leaves thoroly. After the alcohol is colored 
a dark green filter into a bottle and keep in a dark place. 

2. Take a small quantity in a test-tube and examine by looking thru it 
toward the window. Note the deep green color produced by the transmitted 
light. Examine it by reflected light, by standing between the window and the 
tube, and observe that the color of the solution appears a deep dull red, some- 
thing like blood. 

3. Take a small quantity of the solution in two test-tubes, and place one in 
the sunlight and the other in a dark box. How long before the one in the sun- 
light fades out? Compare it with the one in darkness. Thus it will be seen that 
sunlight when too intense will rapidly change the character of chlorophyll, altho 
it is generally absolutely necessary for its development. 

CVI 1 1. Latex. 

1. Take one of the large, red, deciduous stipules which cover the terminal 
bud of Ficus eldstica at the time when it is becoming transparent, a few days 


before it is ready to fall. Examine immediately by holding the stipule with the 
inner side upon the stage of the microscope and examine with low and high power. 
Note the complex system of lactiferous ducts and the movement of the latex in. 
them caused by its escape from the torn end of the stipule. At times the flow in 
the ducts appears to be very rapid. 

2. Mount some of the latex and examine under high power. Note the spher- 
ical granules and draw. These are the rubber globules. 

3. Why does the stipule become colored before it drops off from the bud? 

CIX. Pollen-tubes in Artificial Cultures. 

1. From an opening anther take fresh pollen of Canna, Hyacinth, or Begonia 
and make cultures in the following solution : 

a. Cane sugar, 6 parts 

b. Gelatin, . 3 parts 

c. Tap water, 91 parts 

Heat the mixture over a water bath till the gelatin is dissolved. 

2. To a cubic centimeter or two of this solution add an equal quantity of 
tap water and filter into a small covered dish. Put the pollen into the solution 
and also make hanging drop cultures, placing the slides into a moist chamber. 

3. In 20 to 24 hours examine and draw several tubes representing successive 
stages of development. Note the rotation of the cytoplasm. 

4. Treat with iodin solution and note the position of the nuclei. 

CX. Karyokinesis. 

Study the nuclear division in specially prepared slides of the root tips of 
Allium cepa L., the common onion. For a detailed study an oil immersion objective 
and compensating oculars are necessary, but much may be learned with the ordinary 
lenses. For staining use the fourth and fifth stains given in the appendix under 
"paraffin imbedding." 

1. Resting nucleus. Draw a cell some distance back of the tip where all the 
nuclei are in the resting condition. Represent the celi wall, the cytoplasm with 
vacuoles, and the nucleus. In the nucleus observe carefully the chromatin network 
with chromatin granules and the nucleoli. The nucleus is enclosed in the nuclear 
membrane. The lightly staining or hyaline substance in the nucleus, seen between 
the meshes of the chromatin network is called achromatin. 

2. Prophase, (a) In the first stage of division the chromatin network is 
transformed into a continuous thread or spirem wound rather irregularly. At the 
same time the incept of the achromatic spindle appears forming two dome-shaped 
projections on opposite sides of the nucleus. This figure is known as the close 
mother skein. Find a suitable figure, draw and describe. 

(b) Later the looped mother skein is formed by the shortening and thick- 
ening of the continuous spirem which is thrown into a definite number of loops, 
the heads of which in typical cases point toward the two poles of the spindle. The 
nucleoli and nuclear membrane begin to disappear and the dome-shaped caps of 
the spindle become more pointed. Draw and describe. 

3. Metaphase. (a) After the nuclear membrane disappears the spirem 
breaks into separate loops which are drawn into the equatorial plane with their 
heads toward the centre. At the same time the spindle continues to elongate. This, 
figure is known as the broken mother skein. Draw and describe. 


(b) When the chromosomes have come into the equatorial plane, there is a 
pause resulting from the seeming pull of the spindle fibers in opposite directions 
and the chromosomes are arranged in a very perfect star-shaped figure known as 
the mother star. Each chromosome has in the meantime commenced to split lon- 
gitudinally. This may be seen in the more advanced mother stars. Draw and 

4. Anaphase, (a) After longitundinal segmentation of the mother chromo- 
somes has taken place, the daughter chromosomes are gradually pulled apart, the 
separation beginning at the heads of the loops. This stage is called metakinesis. 
In very favorable sections, centrospheres or small round bodies may be seen at 
the poles of the spindle, also polar radiations, but these can only be studied favor- 
ably with an oil immersion lens. Draw and describe. 

(b) After the chromosomes have been completely separated they arrange 
themselves in star-shaped figures around the poles, while a central spindle of 
threads appears between the two stars. This is the daughter star stage. Draw and 

5. Telophase, (a) The chromosomes being oriented around the poles, now 
begin to contract, becoming wavy in outline, and the free ends curve inward. The 
threads of the central spindle begin to thicken preparatory to the formation of the 
cell plate. Then the central spindle begins to bulge outward until it reaches the 
cell wall. Nucleoli begin to appear. In favorable figures the polar radiations are 
quite prominent and two centrospheres may be seen at the poles under a high 
objective. This stage is called the loose daughter skein. Find a suitable figure, 
draw, and describe. 

(b) After the daughter cells are completely separated by the new cell wall 
the threads of the central spindle and the radiations around the poles disappear, 
and nuclear membranes appear around the daughter nuclei. The chromosomes 
begin to be transformed again into an expanding chromatin network. This is 
known as the close daughter skein. Select a suitable figure, draw and describe. 

6. Make a series of diagrams showing the changes in the chromatin from one 
resting stage to another. 

CXI. The Reduction Division. 

Study specially prepared slides of the ovularies of Lilium philadelphicum L., 
■or the stamens of Lilium tigrinum Andr. The best preparations can probably be 
obtained from the stamens of Lilium tenuifolium Fisch. Delafield's hsematoxylin 
stain will bring out the chromatin well. The proper stages are obtained some time 
before the flower opens. In the ovule of Lilum the archesporial cell is transformed 
directly into the megasporocyte and this divides to form the first two cells of the 
•embryosac, no true megaspores being formed. During this karyokinesis the chro- 
mosomes are reduced and undergo a qualitative division. 

Instead of Lilium the common Hyacinth may be used and will give excep- 
tionally good slides for studying and counting the eight bivalent chromosomes. 
Plant Hyacinth bulbs about October 22, in sawdust, and kill the flowers about 
November 1. The root-tips may be used for the vegetative karyokinesis. Stain in 
Delafield's hematoxylin. 

1. Under an oil immersion lens, study the early stages during which the chro- 
matin network is being transformed into a spirem. Draw and describe. 

2. Draw the stage when the spirem shows a single row of chromatin granules. 

3. Study the stage in which the chromatin granules are dividing preparatory 
to a longitudinal splitting of the linin thread. Draw. 


4. Study the stage in which the spirem, after the chromatin granules have- 
divided, is twisting up into loops. There are twelve of these loops which will 
break apart and form the twelve chromosomes; just half as many as in the- 
previous divisions during the life of the sporophyte. Draw carefully and make a- 
diagram representing a loop and the arrangement of the chomatin granules. 

5. Draw a chromosome just after the loops have broken apart, showing the 
twisted spirem and the closed head end of the loop. These are bivalent chromo- 
somes made up of two univalents which are synaptic mates. 

6. Draw a spindle in the mother star stage showing the fully developed 
chromosomes. Make a diagram illustrating the structure of a chromosome. Count, 
the chromosomes in a favorable cell. 

7. Study the metakinesis stage when the chromosomes have partly untwisted 
and appear like elongated bands on the spindle, just before they break at the 
center. Draw. Make a diagram showing how the chromosome is attached to the 
spindle and how it divides. 

8. Make a drawing of the early daughter star stage when the division of the; 
chromosomes is complete. 

9. Make a series of diagrams showing the changes in the chromatin from the 
early stage of division to the daughter skein stage. Compare the reduction 
division with the vegetative division where longitudinal splitting of the chromo- 
somes takes place. 

CXI I. Fluctuating Variability. 

One thousand soy beans (Sofa max (L.) or other suitable seeds, all taken 
from successive plants until the number is procured, may be weighed and assorted 
into glass tubes, each tube containing the beans weighing within 25 milligrams of 
each other. If small beans are used, a 10 milligram interval may be employed; or 
if large beans are at hand, a 50 milligram interval in weighing will give satisfactory 
results. The tubes may be placed in a box or frame and one or a few sets, if" 
properly managed, will be sufficient for the class. In small classes each student 
may weigh a thousand beans, if suitable balances are at hand. 

1. Count the beans in each tube and make a proper tabulation of the number 
for each weight. 

2. Make a series of slender, contiguous rectangles with equal bases and by 
shading show diagramatically the difference in number of the various weights 
of beans. 

3. Plot a frequency curve showing the fluctuation of the 1000 beans. Could 
you state a principle relative to the abundance of the largest and smallest beans as. 
compared with those of intermediate weight? Look up Quetelet's law. 

CXIII. Mendelian Principles of Heredity. 

Take pure white and pure red dent corn or flint corn and cross pollinate them- 
— i. e. put pollen of red dent on the stigmas (silks) of white dent or the same 
for the flint corn if desired. Keep the silks covered properly to prevent the access 
of foreign pollen. Keep samples of the parent type of ears. Plant the hybrid corn 
and pollinate the hybrid plants among themselves. The hybrid corn will all 'have' 
grains with red pericarps (sporophyte character). Plant the red grain and in 
the next season there will be \ white corn plants and f red corn plants. The white 
if kept separate will remain white pure, but I of the red will give pure red and § 
of it will give red and white again in the proportion of 3:1. It will be seen,. 


therefore, that \ was pure red, \ pure white, and £ hybrid red. The type ears 
of the original parents and of the three succeeding generations are to be ar- 
ranged and labeled in proper order in a glass case or glass jars and the student 
is to note the striking hereditary results. 

Also have corn showing first generation hybrid ears with purple and white 

1. Note that in the first hybrid generation (Fi) the red color only appears. 
The red is thus said to be dominant over the white. 

2. Note that in the second hybrid generation (F 2 ) pure white corn is again 
produced from the red. The white character is said to be recessive to the red. 
Note that there is no blending of the two characters red and white but that 
the white is developed as pure from the red. Note the ratio between the red and 
white. Let R stand for red and w for white and if in the Fi generation eggs 
are produced having the R heredity and others having the w heredity and if the 
same is true for the sperms, make a diagram showing all possible combinations 
that could occur in fertilization of these two kinds of eggs and two kinds of 
sperms. Using the letters R and w as symbols, arrange the combinations on a 
checkerboard of the proper number of squares. 

3. Note the results in the third generation (F 3 ), (a) that the whites pro- 
duced only whites, (b) that h of the reds produced only reds, and (c) § of the 
reds, i. e. | of the F 2 generation, produced both reds and whites again in the ratio 
of 3:1. 

4. Make a diagram with braces showing the inheritance from the original 
pure parents to the third generation of offspring. 

5. Note that these generations of corn illustrate the main facts of Mendel's 
laws of heredity — namely, (a) dominance and recessiveness, (b) the lack of 
blending of certain hereditary factors or the characters resulting from their 
activity during development, and (c) the segregation of the factors and char- 
acters in definite ratios. 

6. If white and purple endosperm characters are hybridized in corn could 
you explain, by remembering tne facts in relation to the female gametophyte of 
the Anthophyta, why in the Fi generation of ears there would be both purple 
and white grains present on the same ear, while in the case of the red and white 
corn the ears (both in the Fi and F 2 generations) were always either completely 
white or red? 

7. If a pure sweet corn ear is pollinated with pollen from both sweet corn and 
field corn (starch corn) all the silks that receive starch corn pollen from which 
fertilization results will show starchy endosperm in the grains, the starchy char- 
acter being dominant. This immediate effect of the pollen is called xenia and 
is the result of triple fusion and dominance. Examine such ears. Under what 
conditions could you tell that the ear had come from a pure stalk of sweet corn? 




In the following account all details are carefully stated, so that a beginner 
should be able, with little outside help, to carry the operations thru successfully. 
The methods employed in preparing plant tissues must be considerably different 
from those used in zoology, since we usually have to deal with a thick cellulose 
wall and a very delicate protoplasm in which are usually contained large vacuoles 
rilled with cell sap, besides numerous plastids and food contents, all of which 
tend to make it difficult to preserve and study the finer details of structure in plant 
cells and tissues. 

The object taken for a trial study may be some root tips of the common onion 
(Allium cepa), or pieces of the young ovularies of some species of lily, as Lilium 
longfflorum or L. philadelphicum. The root tips may be grown by placing an 
onion in a flower pot with moist sawdust, and keeping it for a few days where 
the roots will grow rapidly. The tips should be cut from one-half to three- 
fourths of a centimeter in length. The lily ovularies may be taken at various 
stages before and after the flowers open, and cut into transverse pieces from 
one-fourth to three-fourths of a centimeter long. 

1. — Killing and Fixing. 

The first thing to do in beginning to prepare any plant tissue for permanent 
mounting is to kill and fix it in such a way that it will preserve the minute struc- 
tures as near the living condition as possible. A sharp knife or scalpel should 
always be used, and great care taken so as not to bruise or injure any of the cells. 

Killing Fluid. — The killing fluid is made up as follows : 

1. Chromic Acid, 0.8 grams. 

2. Glacial Acetic Acid, 0.5 cc. 

3. Water, 99.0 cc. 

Have the killing fluid in a 4 oz. (120 cc.) bottle with a common cork. Sixty cubic 
centimeters (2 oz.) of the fluid will be enough to kill one or two dozen objects 
the size of the root tips. The material must be perfectly fresh and put into the 
killing fluid as soon as cut. They will usually sink to the bottom after a short 
time, especially if they are shaken a little from time to time. If much trouble is 
experienced in having the objects float on the surface of the killing fluid, they may 
first be immersed for a very brief moment in 95 per cent, alcohol, and immediately 
after dropped into the killing fluid. This will cause them to sink; or force them 

' ( 8» ) 


down with a plug of cotton. The objects must be kept in the killing fluid from 
twelve to twenty-four hours. The onion root tips should be left at least twelve 
hours; for larger objects, a proportionately longer time. 

2. — Washing. 

After the tissues have been thoroly killed and fixed, the next thing neces- 
sary is to wash out the acid. This may be done by pouring off the acid and filling 
the bottle with water, and changing from time to time. They should be washed 
in this way from one to four hours, depending on how often the water is changed. 
A better way, however, is to set up and use the apparatus described as a con- 
venient washing apparatus in this appendix. The water used for washing should 
.be rather pure. If this is not the case, distilled water had better be used. 

3. — Dehydrating and Hardening. 

The next step is to remove all water from the tissues, and this must be done 
very gradually or the tissues will shrink and the protoplasmic contents of the cells 
will be distorted so that the preparations will be worthless. To remove the water 
successive grades of alcohol are used. During this process the objects may still 
be kept in the same bottle. The amount of each grade of alcohol should be 
sufficient to cover the objects well. The various grades of alcohol should be made 
up and kept in a special set of bottles. It is best not to use the alcohol more than 
once for this process. Carry them thru in the following order : 

1. 10 per cent. Alcohol, 4 hours. 

2. 25 per cent. Alcohol, 4 to 8 'hours. 

3. 35 per cent. Alcohol, 4 to 8 hours. 

4. 50 per cent. Alcohol, 4 to 8 hours. 

5. 70 per cent. Alcohol, 48 hours. 

The objects should be hardened in the 70 per cent, alcohol at least two days, 
■and a longer period is generally better. They may be kept in 70 per cent, alcohol 
for several months without injury. 

6. 85 per cent. Alcohol, 12 hours. 

7. 95 per cent, Alcohol, 4 to 8 hours. 

8. 100 per cent. Alcohol, 4 to 8 hours. 

As a general rule, it is convenient to make three changes a day, morning, noon, 
and night, except the 70 per cent. 

. 4. — Clearing. 

The objects must now be put into some fluid which will dissolve paraffin. 
The best reagent for this purpose is chloroform. 

1. Add one-third c'hloroform to the absolute alcohol. Let stand from four 
to eight hours. 

2. Add enough chloroform to make a two-thirds solution, and let it remain 
from four to eight hours. 

3. Transfer to pure chloroform and leave from six to twelve hours. 

5. — Imbedding in Paraffin. 

The objects are now ready for the paraffin. This should be of good quality, 
with the melting point at 40 degrees or 50 degrees C. The paraffin must be added 
.gradually, in the following manner: add small pieces of cold paraffin to the chlo- 


roform in which the objects are, sufficient to form a cold saturated solution. 
After the cold chloroform has taken up all the paraffin possible, say after about 
six or eight hours, the objects must be gradually brought into the hot water oven. 
This may be of various designs and sizes. A square oven with a side door is 
very convenient and cheap. The oven should be kept at a uniform temperature 
of about 52 degrees C. The bottle may first be placed on top of the oven, and 
then inside. When warmed up to the temperature of the oven, melted paraffin, 
kept in a suitable dish in the oven, may be added from time to time, at intervals 
of two or three hours. At the same time some of the mixture of chloroform and 
paraffin is poured off until the objects are in pure melted paraffin, with all traces 
of chloroform removed. The objects should stay in the oven at least a day, and 
several days will do no harm if the temperature is uniform. It usually takes- 
two days for the operation. One day, however, is long enough unless the objects 
are very large and difficult to penetrate. 

Making the Cake. 

The final imbedding can be easily done in the following manner : use a Petri 
dish of proper size, 80, 120, or 150 mm. in diameter, depending on the amount of 
material to be imbedded; or the paraffin imbedding dish described further on in 
this appendix. Before imbedding, apply a very thin coat of a 50 per cent, aqueous, 
solution of glycerine to the parts of the dish with which the paraffin will come 
in contact, and pour in a suitable amount of melted paraffin to make the cake. 
The objects being in the bottle with the cork, turn the bottle upside down and 
allow the objects to settle on the cork. Then remove the cork and let the paraffin 
in the bottle, with the objects, fall into the dish. The objects may be arranged 
in the paraffin with hot needles. Put the dish quickly into cold water, but do not 
let the water flow into the dish until the paraffin is hard enough to bear the weight 
of the water without being distorted. The paraffin cake must be cooled very 
rapidly, and this is usually done best in cold flowing water. After the cake is. 
thoroly hardened it is carefully removed from the dish and laid aside until used. 
When the objects are once properly imbedded they can be preserved for an in- 
definite period if kept in a cool place. The bottle in which the objects were kept 
while passing thru the paraffin may be used for the same purpose for subsequent 
imbeddings thus saving the trouble of cleaning out the paraffin each time. After 
the objects are in pure chloroform they can be poured into this bottle, which 
will have some paraffin adhering to its walls. 

7. — Cutting Sections. 

The sections must be cut on a microtome. Cut one of the objects with a 
suitable amount of paraffin out of the cake by means of a sharp scalpel, taking 
care that the edges of the block will be parallel with the general contour of the 
object. Trim the block down to a rectangular shape and fasten it to a block of 
wood, or a special holder which goes with some microtomes. Before attempting 
to fasten the block to the holder, have the top of this covered with a cushion of 
paraffin. The paraffin block must be fastened firmly, and the edges especially 
sealed with a hot needle so that there will be no danger of having it come off. 
After having cooled off the block in cold water and trimmed the sides to be 
parallel, fasten it into the clamp of the microtome and adjust the knife and clamp 
so that the knife will strike the paraffin block perfectly parallel. The block should 
be arranged with its long axis parallel to the knife edge. The ribbon of sections 
should be straight and not coiled. If the ribbon coils, no good mounts can be 


made even if everything else has been satisfactory so far. The desirable thickness 
of the sections depends somewhat on the nature of the material and the object to 
be attained. As a general rule most sections may be cut ten microns (/*) thick. 
The section knife or razor must be sharp and clean, with not trace of the smallest 
notches, at least in that part with which the cutting is done. It is well to examine 
the edge of the knife under the low power of the microscope to see that it is in 
.good condition. After the ribbon has been cut care should be taken to have all 
the pieces arranged in a continuous series, from left to right, on a clean sheet 
of paper. The sections may be covered with a wide bell jar. If the sections do 
not hold together well while cutting, the paraffin may be too cold or there may be 
other defects. These should be discovered and removed before proceeding further. 
Ribbons should be cut yards in length, without a single break, when serial sec- 
tions are cut. 

8. — Mounting. 

1. Take a clean slide and put a small drop of albumen fixative on it. Spread 
it out over the surface with the finger into a very thin, even layer, being careful 
that no part of the finger touches the slide before being covered with a layer of 
the albumen. The layer must be quite thin so that you can just leave a noticeable 
impression of your finger on it. Too much albumen will ruin the preparation. 
The albumen fixative is made as follows : 

1. 25 cc. of the white of a fresh hen's egg. 

2. 15 cc. of glycerin. 

3. 0.5 gram sodium salicylate. 

Shake well and filter. This will keep well for a long time. 

2. Now lay the slide down on the table and put a few drops of distilled 
water on it, on top of the albumen film. Care must be taken here that the water 
will not flow over the edge of the slide. 

3. Cut the ribbon into suitable lengths, according to the size of the square 
or oblong cover-glass, discarding the ends of the ribbon which do not contain 
sections. With a scalpel lay the pieces of ribbon on the water in the center of 
the slide in such a manner that one may begin at the upper left-hand corner and 
follow the sections in lines, as one reads the words on this page. Allowance must 
always be made for a certain amount of stretching of the ribbons when they are 
heated, as they are always more or less ruffled. Never press the section down 
with the finger or by any other means, else the fine structure will be broken and 

4. Warm the slide gently by putting it on the paraffin oven or holding them 
over a flame until the heat has straightened out the sections on the water, but do 
not let the sections get so hot as to melt the paraffin. The slides may now be 
placed on wooden blocks, which may be kept constantly on top of the oven for 
this purpose. It is best to let them remain for about twelve hours, when the 
water will all be evaporated and the sections firmly dried to the slide. Four, 
eight, or more slides can be carried thru at one time just as well as a single one. 

9. — Staining. 

The sections are now ready for the staining. One must have the following 
Stender dishes (60 mm. diameter x90 mm. high) : 

1. Filled with turpentine. 

2. Filled with xylol. 


3. Filled with absolute alcohol. 

4. Filled with 95 per cent, alcohol. 
0. Filled with 85 per cent, alcohol. 

6. Filled with 70 per cent, alcohol. 

7. Filled with 70 per cent, acid alcohol (1/10 cc. HC1 to 100 cc. 


8. Filled with 50 per cent, alcohol. 

9. Filled with 25 per cent, alcohol. 

10. Filled with distilled water. 

The various stains used may also be kept in Stender dishes if no special staining 
dishes are at hand. The following stains are recommended for general purposes : 

1. Anilin saf ratlin, alcoholic (50 per cent.) solution, made by combining 
equal parts of anilin water and a saturated alcoholic (95 per cent.) solution of 
safranin. The anilin water is prepared by shaking up anilin oil in distilled water. 
About 3.5 per cent, of anilin oil will be taken up by the water. 

A good anilin safranin may also be made as follows : 

Make a 10 per cent, solution of anilin oil in 95 per cent, alcohol. When the 
anilin oil is dissolved, add enough water to make the whole mixture 20 per cent, 
alcohol (-see paragraph on "Grades of Alcohol"). Add 1 gram of safranin to 
each 100 cc. of this solution. 

The safranin soluble in alcohol is the better one to use altho the safranin 
soluble in water will also be satisfactory. 

2. Gentian violet, a 2 per cent, aqueous solution. 

3. Iron alum, a 2 per cent, aqueous solution of ammonia sulphate of iron. 

4. Haematoxylin, a 0.5 per cent, solution obtained by dissolving in hot water. 

5. Delafield's Haematoxylin, to be obtained ready prepared from the dealers, 
or prepared according to the directions given farther on. 

The remaining Stender dishes will therefore be as follows : 

11. Filled with anilin safranin. 

12. Filled with gentian violet. 

13. Filled with iron alum. 

14. Filled with haematoxylin. 

15. Filled with Delfield's haematoxylin. 

Preparation for Staining Bath. 

1. Melt the paraffin around the sections of two slides by heating them to 
52 degrees C. in the paraffin oven. 

2. Wash off the paraffin by putting the two slides back to back into the 
Stender dish with the turpentine. 

3. Transfer to Stender dish of xylol. 

4. Next put them in succession into the dishes with absolute alcohol, 95 per 
cent., 85 per cent., 70 per cent., and 50 per cent., or to whatever grade of alcohol 
is present in the staining solution. If the stain is an aqueous solution pass down 
thru 50 per cent, alcohol to 25 per cent, and then to water. Let them remain 
in each one about ten seconds, more or less. Do not leave the dishes uncovered 
longer than necessary. In passing the slide thru the solutions it is convenient 
to take two at once placed back to back. 



1. Run the slides down thru the grades of alcohol to the 50 per cent. 

2. Transfer the slides from the 50 per cent, alcohol to the anilin safranin 
dish, and let them stain from two to twelve hours or longer. 

3. When the sections are stained wash them successively in the 50 per cent, 
alcohol, 70 per cent., 85 per cent., 95 per cent., and absolute alcohol. Judgment 
must be used as to how fast the transfer is to be made from one grade of alcohol 
to the other. They must generally be taken quite rapidly, as the alcohol will take 
out such stains as safranin. 

4. Cear the sections by transferring them to the xylol. The sections must 
be thoroly cleared. Leave them in xylol until they look transparent. 

5. Take one slide out of the xylol at a time ; wipe off the xylol with a clean 
rag, wiping quite close to the sections, but do not touch the sections. 

6. Put a drop or so of Canada balsam (dissolved in xylol) on the sections at 
one side. 

7. Put on a clean cover-glass in the following manner : holding the cover- 
glass with the edges between thumb and forefinger, bring it down slowly and 
obliquely upon the drop so that one edge of it is first wefted by the balsam ; and 
supporting the opposite edge with a needle, let the cover gradually settle down 
and spread out the balsam. There should be no air bubbles and just enough 
balsam to come to the edge of the cover-glass. Care must be taken to not let 
the sections become dry at any stage of the foregoing process. The slides may 
now be laid aside into a convenient place to dry. They may be studied imme- 
diately if handled with care for a few weeks until the balsam has thoroly hard- 
ened around the cover-glass. If balsam should get on the hands or instruments, 
it can easily be removed with a little xylol. 


This makes a good double stain for many purposes. Stain first in the anilin 
safranin from two to twelve hours; then wash in 25 per cent, alcohol; next in 
water; and then stain from one to four minutes in the gentian violet. After 
washing in water, pass thru the grades of alcohol, clear in xylol or clove oil, and 
mount in balsam. 


Run the slides down to water, and from this transfer to the iron-alum. Keep 
the sections in this from two to four hours, and after washing well in tap water, 
stain for twelve hours (or over night) in the hematoxylin. After this wash the 
slides again in water and wipe them clean, and as close to the sections as is safe. 
The sections are now black and must be cleared. To do this they are placed again 
in the iron-alum, which gradually takes out the excess of satin. They must be 
closely watched and examined from time to time under the low power of the 
microscope. When of a light greyish-blue color they are washed again very thoroly 
in tap water so that all iron salt is removed, and are then carried thru the grades 
of alcohol, cleared in xylol, and mounted in balsam. If the iron-alum will not 
remove enough of the stain use the acid alcohol after taking the slides thru to 
the 70 per cent. 



After one has become accustomed to use the foregoing combinations success- 
fully, the following is well worth trying : Stain first in anilin saf ranin or in anilin 
.safranin and gentian violet, as described above; wash in water; and then stain 
in the iron-alum-hsematoxylin according to the directions given, just as tho the 
sections had not been stained at all. After staining, removing excess of stain, 
and washing in tap water, pass thru the grades of alcohol, clear in xylol, and 
mount in balsam. This is one of the clearest stains. 


In staining proceed as follows : Transfer to the stain from 25 per cent, alcohol; 
stain one to four hours. Wash in tap water until the rmrple color develops. Pass 
thru the alcohols to 70 per cent. Dip the slides rapidly into acid alcohol. Run 
back to water and let remain until the purple color is restored. Pass thru the 
alcohols, clear in xylol, and mount in balsam. 


According to Bolton and Harris, "the method consists essentially in placing 
the fresh tissues in a hot 2 per cent, solution of agar-agar to which 10 per cent, 
of formalin has been added. The temperature of this fluid should be kept at 
about 70° C. After remaining in the solution from one to several hours, the 
tissues are removed and attached to blocks with a 5 per cent, solution of agar- 
agar containing 10 per cent, of formalin. The heat and the formalin harden and 
fix the tissues at the same time the agar-agar impregnates it. After fixing the 
tissues to blocks these are placed in 95 per cent, alcohol and allowed to remain 
from two to four hours, and the tissues are then ready to be cut into sections 
which can be stained, cleared, and mounted on slides in the usual way employed 
for celloidin sections." 

The 2 per cent, solution of agar-agar can be made as follows: Take 1 gram 
of agar-agar to 50 cc. of distilled water and boil for two hours. Then pour the 
hot solution into a high cylinder and allow it to cool slowly until the cloud has 
fallen. After the solution has cooled, cut off the clear upper portion and put it 
in a glass jar. Place the jar in a basin of water and heat it until the agar-agar 
is melted. Then add formalin' in the proportion of 1 part of formalin to 9 parts 
by volume of the melted agar-agar. 

The 5 per cent, solution is made in the same way as the 2 per cent., only 1 
gram of agar-agar to 20 cc. of distilled water are taken. Formalin should be 
added in the same manner and proportions as in the 2 per cent, solution. The 
5 per cent, solution when melted is quite fluid, but when cold it is more firm. It 
becomes much firmer on the blocks after exposure to the action of strong alcohol. 
Large quantities of the agar-agar solution can be prepared and preserved in air 
tight vessels to prevent evaporation. 

For fixing and imbedding only a small amount of the agar-agar solution need 
to be taken. The solution should be kept at a temperature of 70° C. The fresh 
tissues are first placed directly into the hot 2 per cent, solution and left for about 
two hours and are then transferred to the 5 per cent, solution and left for one 
hour or more, when they are ready to be imbedded. The tissues are imbedded 
on wooden blocks. With a small camel's hair brush put a layer of the hot agar- 
agar on one end of the block, let it cool for a few seconds and then place one 
of the pieces of material on the block. Cover with more of the agar-agar solution 
until properly imbedded. After fixing the tissue to the block, place in 95 per cent. 


alcohol and let remain for tv/elve hours. The longer the agar-agar remains in the 
alcohol the tougher it becomes. 

Instead of imbedding directly on the block the objects may be poured into a 
suitable dish with a proper quantity of thick agar-agar and when sufficiently firm 
the cake may be cut into suitable cubes. The cubes containing the objects are 
kept until properly hardened in 95 per cent, alcohol when they may be fastened 
to the wooden blocks and sectioned. 

Leaves or stems containing considerable silicon may be first placed for 12 
or more hours in a 5 per cent, aqueous solution of hydrofluoric acid and after 
washing in water imbedded as described above. 

The material is sectioned on a sliding microtome in the same way as with the 
celloidin method. The knife must be kept wet with 95 per cent, alcohol as well 
as the blocks during the sectioning. The sections may be stained with safranin 
and gentian violet, Delafield's hematoxylin or other favorable stains. 

This method is applicable where a histological study of the plant tissue is 
desired, but does not seem satisfactory for cytological work. 

It is often desirable to use the agar-agar method of imbedding and at the 
same time preserve the sections in series. This can be accomplished very easily 
by a combination of the agar-agar and paraffin methods. Such objects as fresh 
leaves and herbaceous stems and fresh or dried leaves with parasitic fungi are 
favorable objects for trial. The tissues are killed and imbedded in the usual way 
as described under the agar-agar method, the imbedding being done on a plate of 
glass. After the agar-agar has cooled for a few minutes the excess is trimmed off 
and the object incased in the agar-agar block is placed directly into 70 per cent, 
alcohol, passed up thru the grades of alcohol, and finally imbedded in paraffin in 
the usual way. The sections will adhere to the slide without the use of albumen 


1. Make a solution of equal parts of absolute ether and absolute alcohol. 

2. Make a 2 per cent, celloidin solution with the ether-alcohol mixture. Use 
prepared celloidin like Schering's Celloidin. Also make 4, 6, 8, 10, 12, 14, 16, 18, 
and 20 per cent, solutions. 

For the 2 per cent, solution take 2 grams of celloidin to 100 cc. of the ether- 
alcohol mixture; for the 4 per cent, solution 4 grams to 100 cc, etc. Keep the 
stock solution well corked. 

1. Treat the fresh material to be imbedded in the same way as for paraffin 
imbedding until it is in absolute alcohol. Leave in the alcohol long enough to 
insure complete dehydration. 

2. Transfer the objects to the ether-alcohol solution and leave 12 to 24 hours. 

3. Next put them into the 2 per cent, celloidin solution for 2 or 3 days. 

4. Transfer the objects for 2 days to the 4 per cent, celloidin solution. 

5. Put them successively for 1 day each into the 6, 8, 10, 12, 14, 16, 18, and 
20 per cent, celloidin solutions. 

6. Finally, if desired, a few dry chips of celloidin may be added from time to 
time until the mixture is quite firm. The bottle with the objects may be kept on 
a paraffin oven at a temperature of about 40° C. if convenient. 

7. The pieces of tissue may now be imbedded and the celloidin hardened in 
one of three ways : 

A. Pour a sufficient quantity of the 20 per cent, celloidin solution into a 
suitable flat dish; take the objects out of the bottle with a pair of forceps and 


place them into this dish, arranging them with sufficient space between; cover 
the dish, but not too tightly; and set aside for about 2 days, when by the evap- 
oration of the ether and alcohol the celloidin will be hard enough to cut into 

Transfer the blocks for about 12 hours into chloroform and then put them into 
a mixture of equal parts of glycerin and 95 per cent, alcohol, where they may be 
kept indefinitely. 

To fasten the celloidin blocks to the wooden blocks used for clamping to the 
microtome, trim with a sharp scalpel, place the under side of the celloidin block 
for a few moments in the ether-alcohol solution, and then fasten it to the wooden 
block which should have a cushion of thick celloidin solution. Let remain for a 
little while to allow the celloidin to harden somewhat and then place into the 
glycerin-alcohol solution until desired for cutting. 

B. The pieces of tissue may be taken at once from the 20 per cent, celloidin 
solution and imbedded on wooden blocks. Place a small quantity of the 20 per 
cent, solution over one end of the wooden block, and arrange a piece of the tissue 
on this cushion. In 3 or 4 minutes pour on a layer of the celloidin solution and 
repeat this until the object is properly covered and imbedded. After about 5 
minutes the block with the imbedded object is placed into chloroform and then 
into the glycerin-alcohol mixture until desired for sectioning. 

C. Take the objects out of the bottle with a coat of celloidin adhering and 
place them for 12 hours in a bottle of chloroform. From this transfer to the 
glycerin-alcohol mixture and leave for a few days or indefinitely. When ready to 
section cover the end of a wooden block or object holder with thick celloidin 
solution, and after trimming the proper end of the block of material and freeing 
from glycerin, fasten to the moist surface of the object holder. 

The sectioning must be done on a sliding microtome. While cutting sections 
the knife and block should be continually wet with 70 per cent, alcohol or with a 
higher grade up to 90 per cent. A camel's hair brush is convenient for removing 
the sections. The sections may be kept in alcohol of from 70 per cent, to 90 per 
cent. In staining, keep the sections in a small Stender dish or other suitable 
receptacle and treat in general similar to ordinary sections or paraffin sections 
passing them up and down thru the grades of alcohol according to the stain 
used. If desirable the celloidin may be removed, before or after staining, by 
placing the sections for 15 minutes into ether. 

Woody tissues may be softened by the use of hydrofluoric acid. A 5-10 per 
cent, aqueous solution of the commercial acid should be used. This may be kept 
in a rubber bottle or in a glass bottle coated on the inside with a thick layer of 
hard paraffin. 

After boiling the blocks of wood place them into the acid for 3 or 4 days, and 
after washing them thoroly in water pass thru the grades of alcohol. Hard 
tissues fixed in the ordinary killing fluids may also be softened by placing them 
for some time into the hydrofluoric acid. 

Various stains may be used, but Delafield's haematoxylin is a good general 
stain for celloidin sections, and the following cleaning mixture will be found 
especially suitable before mounting in Canada balsam : 

Turpentine, 3 parts. 

Carbolic Acid, 2 parts. 

I. 7 




Infiltrate with celloidin in the usual manner, and when in the thick celloidin 
place the object in a large quantity of pure chloroform either with or without 
any quantity of the celloidin adhering to its outer surface. After leaving 24 hours 
in the chloroform remove the objects to a bath of l /z chloroform and y 2 cedar oil. 
In 24 hours place in the oven in paraffin of the grade used for imbedding. Several 
changes are necessary and more time must be allowed than for tissues imbedded 
by the plain paraffin method. Paraffin will penetrate the celloidin itself and the 
mass cuts with much less vertical compression than in the case of objects in 
pure paraffin. 


Difficulty is sometimes experienced in imbedding small bodies to be sectioned 
in large quantities, such as pollen grains, spores, unicellular algae, etc. The follow- 
ing method will give good results : 

The spores are placed in a homeopathic vial and treated in the ordinary way 
for paraffin imbedding. The objects will sink to the bottom and the different 
reagents can be easily poured off. When the material is ready the bottle is rilled 
with paraffin and after the .spores or other objects have settled to the bottom it is 
quickly cooled off. When the paraffin is hardened the bottle is broken and with 
a little trimming the block is ready for the microtome. 


To 100 cc. of a saturated solution of ammonia alum add, drop by drop, a 
solution of 1 gram of hsematoxylin dissolved in 6 cc. of absolute alcohol. Expose 
to the air and light for 1 week; then filter. Add 25 cc. of glycerin and 25 cc. of 
methyl alcohol. Let the solution stand until the color is rather dark. Filter and 
keep in a tightly stoppered bottle. The solution should stand for 2 months before 
it is ready for use. 


Safranin, according to the formula given in the general method for paraffin 

Gentian violet, a 2 per cent, aqueous solution ; orange G., a 1 per cent, aqueous 
solution. Stain 12 hours in the safranin; wash rapidly in 50 per cent, alcohol, 
25 per cent., sand water. Stain 2 hours in the gentian violet. Finally stain 1 minute 
in the orange G. Wash rapidly in 50 per cent, alcohol, 85 per cent., and absolute 
alcohol. Clear in clove oil about 10 seconds. Replace with cedar oil. If not too 
dark mount in balsam'; if still too dark apply more clove oil. 


Make a 1 per rent, aqueous solution. Stain 15 to 25 minutes, or much longer, 
according to the material. This stain is good for free hand sections of alcoholic 
material like the leaves of pine, etc. If sections .have been overstained they may 
be differentiated in a 1 per cent, solution of picric acid in 70 per cent, alcohol; 
leave about 30 seconds and wash in 70 per cent, alcohol until the red color is 
replaced, after which pass thru the grades as usual. 



Preparations stained in several colors are not always the best to show details 
of structure. For ordinary class work, however, sections which bring out the 
various cell organs in distinct colors are very convenient and to a large extent 
preclude misinterpretations. The following will be found good for ordinary root 
tips and the material must be killed in chrom-acetic acid : 

Stain first two or three hours in anilin-safranin. Next stain for about thirty 
minutes in an aqueous solution of picro-nigrosin. The picro-nigrosin must be made 
in the following proportions : 

Distilled water, 100 cc. 

Picric acid, 1 gram. 

Nigrosin, 1 gram. 

First dissolve the picric acid completely and then add the nigrosin. After 
staining, dehydrate and mount in balsam. The stain is permanent, and if porperly 
done the results will be as follows: cell wall well stained and back; cytoplasm 
of a bluish color; spindle threads bright green; chromatin network and chromo- 
somes brick red; nucleoli bright red; thickened connecting fibers of the central, 
barrel-shaped spindle dark green and prominent; granules of the cell plate black. 


Make a strong solution of potassium iodide in distilled water; to this add 
crystals of iodin until a saturated solution is obtained. This may be diluted 
with distilled water until it is of a clear, reddish-brown color. 


1. Dissolve 110 grams of zinc in 300 cc. of pure hydrochloric acid and evap- 
orate to 150 cc. 

2. Dissolve one gram of potassium iodide in as little water as possible and 
add 0.15 grams of crystals of iodin. 

3. Mix (1) and (2). 

A good temporary stain for fresh or alcoholic material. 


Make a 2 per cent, aqueous solution of glacial acetic acid and add a little 
methyl-green. This fixes and stains nuclei of fresh material fairly well. After 
staining wash in 1 per cent, acetic acid and mount in weak glycerin. The stain 
fades rapidly. 


Make a 2 per cent, solution in 70 per cent, alcohol. This is good for cell 
walls but not for protoplasm. Stain about 30 minutes. 


Dissolve phloroglucin in methyl alcohol (wood alcohol) until a saturated solu- 
tion is obtained ; then add gradually strong hydrochloric acid until precipitation 

Use on fresh material or alcoholic material. Lignified walls assume a bright 
red color. Sclerenchyma is also stained strongly by this solution. 



Make a saturated solution in 70 per cent, alcohol. This is good for temporary 
mounts of fungi. 


Make a saturated solution in pure water. This is good for temporary mounts 
of fungi making evident transverse septa, etc. 


It is generally desirable to have students do their own staining so far as time 
will permit. Most good strains act too slowly to make this possible. An aqueous 
1 per cent, solution of gentian violet or of fuchsin will give fair results on sections 
of rhizomes, stems, roots, and wood. The sections can be stained all together in a 
dish or one or more may be placed on a slide and covered with a drop of the 
gentian violet. After staining from 1 to 4 minutes and dehydrating, mount in 
Canada balsam and study immediately if necessary. A 1 per cent, aqueous solution 
of equal parts of gentian violet and safranin is very good for some objects. 

The process in detail is as follows : Cut sections and place in 70 per cent, 
alcohol ; wash in water ; stain ; wash in water, in 70 per cent, alcohol, in 95 per 
cent, alcohol, in absolute alcohol; clear in xylol; mount in balsam. 


One per cent, of fuchsin in 95 per cent, alcohol, stain for a few minutes and 
wash again in 95 per cent, alcohol. This gives a fair stain to root tips with 
very little manipulation. 


A very good and desirable stain for starch may be obtained by the use of 
anilin-safranin and gentian-violet. 

1. Anilin-safranin. Alcoholic fifty per cent, solution, prepared by combining 
equal parts of anilin water and a saturated alcoholic ninety-five per cent, solution 
of safranin. 

2. Gentian-violet. A two per cent, aqueous solution. Stain from two to four 
hours or more in the safranin and from two to eight minutes in the gentian- 
violet. The slides should be taken thru the alcohols quite rapidly, or too much 
of the stain will be washed out. 

This medium modified as follows is good for various objects. 

1. Gum arabic dissolved in cold water (eough 

to make a thick gum) 20 cc. 

2. Glycerin 4 cc. 

3. Chloral hydrate 1 cc. 

4. Alcohol (95 per cent) 1 cc. 

5. Glacial acetic acid 1 cc. 

Care must be taken in adding the alcohol and acid to avoid coagulation. 
Various fresh objects, as spores, small gametophytes, fungi, etc., can be mounted 
in this medium directly from water or 95 per cent, alcohol. 



The following method will be found satisfactory for making permanent glycerin 
slides. The objects are taken from water to the pure glycerin by adding the 
glycerin gradually and permitting the water to evaporate until absolutely pure 
glycerin alone is left. The objects are then placed in a small drop of glycerin 
jelly on the slide and a ring of Canada balsam is placed around the drop, after 
which the whole is covered with a square or round cover-glass. The glycerin 
adhering to the objects may be drained off by placing them on a clean piece of 
blotting paper before transferring them to the drop of glycerin jelly. The glycerin 
jelly and balsam will not mix, and if the two mounting fluids have spread out 
properly the slide should be perfectly sealed. Such slides need not be sealed in 
any other way. 

This method is suitable for various algae, molds, powdery mildews, hairs, 
scales, and many other objects. 


Place the diatoms or other like objects in 95 per cent, alcohol. Put a drop 
of the alcohol, with diatoms, on the slide ; dry over a flame ; cover with xylol ; 
and when clear, mount in balsam. 


To mount spores of fungi, ferns, lycopods, etc., also myxocycetes, apply a layer 
of albumen fixative, sprinkle the spores on this, dehydrate with absolute alcohol, 
clear with xylol, and mount in balsam. 


When only external characters are desired very good mounts can be made in 
the following manner: Put a drop of albumen fixative on the slide and spread 
it out in a thin layer, sprinkle the fresh pollen on this, then put the slide into a 
Stender dish of absolute alcohol to which equal parts of a small amount of safranin 
and gentian violet have been added. About 0.1 gram of each to 100 cc. of alcohol 
is the proper amount. After 5-20 minutes transfer to absolute alcohol, clear in 
xylol, and mount in Canada balsam. 


Place beside the cover glass a drop of 50 per cent, glycerin, letting the drop 
just touch the water of the mount, when it will be drawn in gradually as the 
water evaporates. This will of course kill any living organisms. 


Boil blocks of a suitable size in water and place in 70 per cent, alcohol. Cut 
on a hand microtome when desired. 


Roots, rhizomes, herbaceous stems, pine leaves, and other herbaceous parts 
are simply placed in 70 per cent, alcohol and preserved until desired for study. 



Sections of wood, stems, roots, etc., may be preserved indefinitely in 70 per 
cent, alcohol. If stained they may be kept in xylol for several days and mounted 
at any time. They should be kept in the dark and carefully corked or stoppered, 
otherwise they may fade and the xylol evaporate. 


Take a ring of glass made especially for the purpose or build up a chamber 
on the slide with paraffin. Put a drop of distilled or boiled water in the bottom 
of the chamber. Apply vaselin to the edge of the ring for sealing. Put a drop 
of water or other culture medium with spores on the center of the slide and place 
gently on the ring with the drop hanging down. 


(a) flem ming's weaker fluid. 

1 per cent, chromic acid, . ..*.".• • • .25 cc. 

1 per cent, glacial acetic acid, 10 cc. 

Water 55 cc. 

1 per cent, osmic acid, 10 cc. 

Add the osmic solution from time to time as the reagent is needed for 
use, since it does not keep well. This fluid is expensive on account of the osmic 

The blackening due to the osmic acid may be removed by placing the slides 
in turpentine exposed to sunlight when they will stain well with a number of 
reagents. The best stain, however, is the safranin, gentian violet, orange G. 


Glacial acetic acid, 0.7 cc. 

Chromic acid, 0.3 gram. 

Water, 99. cc. 

This is good for algae, root tips, and other delicate material. It causes little 
or no plasmolysis. It is improved by adding for each 10 cc. (as it is used) one 
drop of a 1 per cent, solution of osmic acid. 


Glacial acetic acid, 0.4 cc. 

Potassium bichromate, 0.6 gram. 

Water, .' 99. cc. 


Use phenol, or equal parts of phenol and bergamot oil, phenol will clear after 
low grades of alcohol, even water. The sections can then be transferred immedi- 
ately to balsam. 


5 per cent, solution of celloidin, .... 1 part. 
Clove oil, 3 parts. 



Nitric acid (10 per cent.) solution, ... 4 parts. 

Alcohol (95 per cent.), 3 parts. 

Chromic acid (£ per cent, aqueous solution), . 3 parts. 

This is good for preparing shell perforating algae and other lime incrusted 

If too slow in action a few drops of nitric acid may be added to the amount 
used, about 2 drops to 10 cc. of the fluid. 


This mixture is used to macerate woody tissues. 

Potassium chlorate, 1 gram. 

Nitric acid, 50 cc. 

The chips or fragments of tissue are boiled in the fluid for a short time in 
a test tube. When the material is sufficiently macerated, pour off the fluid, wash 
well in water and after teasing the specimens apart with needles preserve and 
mount in glycerin. 

The boiling should be done out of doors or under a hood as the acid vapors 
are very corrosive and injure microscopes and other metallic apparatus. 


Camphor, 20; grams dissolved in 50 cc. of 95% alcohol. 

Glacial acetic acid, 100 cc. 

Copper acetate, 30 grams. 

Copper chloride (Cu. C1. 2 ), . . . . . 30 grams. 

Distilled water, 15 liters. 

A larger or smaller quantity may be made in the same proportions. This 
solution is valuable for preserving green algae, liverworts and other green plants. 


General pharmaceutical rule for making any lower grade or percentage of 
alcohol from any given grade or percentage. 

Take of the grade at hand as many volumes as the number of the per cent, 
you wish to make; then add to this enough volumes of pure water to make the 
total number of volumes agree with the number of the per cent, at hand. 

For example, suppose you have 95 per cent, alcohol at hand and wish to make 
70 per cent, alcohol, take 70 cc. of the 95 per cent, alcohol and add to this 25 cc. 
of pure water. This will give you 95 cc. of 70 per cent, alcohol. 


Various methods have been described for labeling slides while they are being 
stained. Very good results may be obtained by the following method : 

The medium used is waterglass, an aqueous solution of sodium- or potassium- 
silicate. It should be thinned if necessary till it will flow well from a pen. 
An ordinary steel pen of the stub or ball-pointed sort is used. After the slides 
are marked they must be heated, either before or after thy dry, preferably by 
holding them for a few seconds in the blue cone of a bunsen flame till the 
waterglass decomposes giving off strong jets of sodium light, and at the same 



time effervescing so as to leave behind a rough sandy surface. This is then 
rubbed down by a single stroke against the edge of the table or any hard object 
and leaves a ground glass surface which, if the fixing has been properly done, is 
permanent and will not be affected by any reagent which does not attack the 
slide itself. If desired some such dye as carmine may be stirred into the solution 
to make the marks more conspicuous. 

Slides may also be marked with hydrofluoric acid as follows : 
Take a clean slide, dip one end into paraffin, and let it cool. With a needle 
scratch whatever mark or number is desired on the paraffined surface, and then 
apply a drop of hydrofluoric acid to the mark by means of a wooden toothpick. 
Let this remain 2-5 minutes ; then melt the paraffin and clean the slide. Any 
number of slides may be marked in a series in this way. Ordinary precautions 
must be taken in handling the hydrofluoric acid. 


The apparatus described below will be found convenient for washing material 
after being killed in an acid or other solution. It consists of a glass or other 

tube of suitable thickness, ten centimeters 
long and from two to three centimeters in 
diameter ; an open brass ring with thumb- 
screw ; a funnel of brass or tin about five 
centimeters wide at the top, four centimeters 
deep, and ending below in an open tube one 
centimeter long; and two cotton or linen 
cloths for strainers. The apparatus is put 
together as shown in the figure, and may be 
supported on a tripod. 

When the objects are ready to be washed, 
remove the ring and cloth and pour the 
objects, with the solution in which they are 
contained, into the tube, and then replace the 
ring and cloth, and let water flow into the 
funnel. Usually it will be found best to let 
the lower part dip into a glass dish. When 
the objects are washed they can easily be 
transferred to a bottle by taking off the cloth 
into which they will have settled. In this way 
small and delicate objects can be handled 
without injury. 

This appartus can also be used as a filter, 
or for collecting small water plants and ani- 
mals. For instance, by having a cloth with a coarser mesh above and a finer 
one below, organisms of a certain size can be collected in the lower cloth free 
from foreign matter or larger animals and plants. 

Fig. 17, 


When imbedding in paraffin a suitable dish must be used. When only a few 
objects are to be imbedded a small paper tray may be made. Petri dishes of 
suitable size may be employed for larger quantities. A dish especially made for 
this purpose will, however, be found most convenient. (Fig. 17.) 


The bottom is a square plate of glass of proper size and thickness, while the 
box consists of an open brass ring with a thumbscrew. The sides of the ring 
should be smooth, and should be of sufficient thickness to secure rigidity. It 
will be found convenient to have rings of several sizes, — 50, 80, 120, and 150 mm. 
in diameter. Before using apply a very thin coat of 50 per cent, glycerin to the 
glass and ring, and place the dish on an ordinary plate so that cold water can 
be run under it. 


A good note book is essential to good work in the laboratory, and tho one 
finds note books of about all shapes, sizes, and qualities, there are few which are 
really satisfactory for laboratory work. The note book should be 7 x 10 inches 
in size. This size is not too large to be easily handled, and is still large enough 
to hold most of the drawings made by the general student. It should be made 
up of two kinds of paper and two paper covers of stiff cardboard, strengthened 
with cloth on the back edges ; all perforated exactly, with three holes (the outer 
holes being two inches from the ends), and tied together loosely with a shoe- 
string. The paper should be unruled, and of good quality, so that the notes can 
be taken in ink; the drawing paper should also be such that a good hard pencil 
or India ink can be used for drawing. A third kind of paper can be used for 
the finer work. 

This note book will lie absolutely flat on the table and there are no trouble- 
some clamps in the way. It can be folded back to back, can be increased indefi- 
nitely in size, and the work can be rearranged in any way desired. Such note 
books can be made by any local dealer at small expense, and the paper sold to the 
students in any quantity and quality desired. 

Substantial cloth covered backs with rings are now available for permanent 
binding, and if properly made are in some respects more convenient than books 
tied with strings. 


A very convenient and serviceable microscope cover can be made from heavy 
manilla paper rolled up and glued together in the shape of a slender cone of 
proper size. A better one can be made in the same way with transparent celluloid. 


All important terms and phrases used have been defined and the derivation, 
when other than Anglo-Saxon, indicated. It was thought advisable to use the 
Latin alphabet in Greek words since very many college students have no acquaint- 
ance with the Greek. 

Ab-nor'mal (organ) [Gr. anomalos] — An organ or part which deviates from the 

usual type in some extraordinary way, as in shape, size, color, or other 

A-bor'tive (organ) [L. abortivus] — An organ or part normal in the species but 

which has failed to reach full development in the individual. 
Aoh-ro-mat'ic spindle [Gr. achromatos] — The spindle shaped figure of threads 

formed in the cell during nuclear division. The spindle is usually not 

stained readily by stains which color the chromatin intensely. 
A-chro'ma-tin [Gr. acroma] — The substance of the nucleus which is not readily 

colored with basic stains. 
Ac'ti-no-mor'phic [Gr. Aktinos + morphe] — Radially symmetrical ; a flower or 

organ which can be cut into similar equal halves by two or more planes. 
A-cu'mi-nate [L. acuminatus] — Tapering gradually to the apex. 
yE-cid'i-o-spore' [Gr. Aikia -|- sporos] — In rusts, one of the nonsexual spores 

produced in chainlike rows in the Aecidium. 
y£-cid'i-um — A cluster-cup, developed in one stage of the life history of certain 

rust fungi. 
yE'ci-um [Gr. Aikia] — The type of sorus which is developed in the first parasitic 

spore-bearing stage of a rust fungus. 
y£-tha'li-um [Gr. aithalos] — A compound sporebearing mass, formed in certain 

slime-molds, by the fusion of many sporangia. 
Al-bur'num [L. albus] — The young, usually light-colored, soft wood of a tree 

next the cambium layer; the sap-wood. 
A-leu'rone grains [Gr. aleuron] — Proteid material occurring in the form of 

minute granules in the seeds of numerous plants. 
Al'ga [L.] — A thallophyte with chlorophyll. 
Alternation of generations — A condition existing in the life cycle of plants in 

which a sexual generation alternates with a nonsexual one. 
A'ment [L. Amentum] — A slender usually flexible spike of flowers, as in the 

An'a-phase [Gr. ana -f- phasis] — The stage in karyokinesis during which the 

daughter chromosomes separate and pass to the poles of the spindle. 
A-moe'boid [Gr. amoibe] — Like an amoeba, especially in its movements or changes 

of shape. 
A-nal'o-gous [Gr. ana -f- logos] — Organs or parts similar in function but not in 

origin and structure. 
A-nas'to-mos'ing [Gr. anastomosis] — Connecting so as to form a network. 
A-nat'ro-pous [Gr. ana + tropos] — An inverted ovule with the micropyle near the 

hilum, the funiculus being united with the body of the ovule. 



An-dre'ci-um [Gr. andros -f- oikos] — The whole set of stamens in a flower. 
An'dro-spo-ran'gi-um [Gr. andros -j- sporos -J- aggeion] — A spore case containing 

An'dro-spore [Gr. andros + sporos] — A small spore in certain algae which gives 

rise to dwarf male individuals. 
An'e-moph'i-lous [Gr. a'nemos — philos] — Pollination by the agency of the wind. 
An'gi-o-sperm [Gr. aggeion -(- sperma] — A seed plant which has the seeds enclosed 

in the carpel, the enclosing case being called an ovulary. 
An'i-so-car'pic [Gr. anisos — karpos.] — Having the carpels of the gynecium fewer 

in number than the parts in the other floral sets. 
An'nu-al [L. annualis] — Yearly; living but one year. 
Annual ring — The layer of wood produced each year from the cambium layer in 

dicotyl and other similar plants. 
An nu-lar wood vessel [L. annulus] — A wood vessel having thickenings in the 

form of rings. 
An'nu-lus [L. annulus] — 'In the agarics a ring of tissue surrounding the stalk; in 

ferns, the ring of cells partly or completely surrounding the sporangium. A 

specialized ring of vesicular cells between the mouth of the sporangium and 

the operculum of a moss. 
An'ther [Gr. antheros] — The spore-bearing part of a stamen; the part which 

finally contains the pollen sacs. 
An'ther-id'i-o-phore [Gr. antheros -\- idion -j- phoros] — An organ or branch which 

bears the antheridia. 
An'ther-id'i-um [Gr. antheros -J- idion] — A male organ of reproduction; a 

An-tho-cy'an [Gr. anthos -j- kuanos] — a coloring matter in plants of various shades 

of blue, red, etc. 
An-tip'o-dal cells [Gr. anti-j-pous] — The cells, usually three in number, at the base 

of the female gametophyte in angiosperms. 
Ap'ic-al cell — The cell in the tip of some bryophyte and pteridophyte stems by the 

division of which the growth in length takes place. 
Ap'o-the'ci-um [Gr. apo + theke] — An open cup-like or disk-like body containing 

asci, in fungi and lichens. 
Ar'che-go 'ni-al chamber [Gr. archegonos] — A small depression at the tip of the 

female gametophyte in the seeds of cycads, into which the necks of the 

archegonia open. 
Ar'che-go'ni-um [Gr. archegonos] — A female organ of reproduction; a special 

kind of ovary. 
Ar'che-go 'ni-o-phore [Gr. Archegonos + pherein] — The branch or structure which 

bears the archegonia. 
Ar'che-spo'ri-al cell [Gr. Arche + sporos] — The cell from which sporocytes are 

finally developed. 
Ar'che-spo'ri-um — The cell or group of cells which give rise to sporocytes. 
A-re'o-la [L. areola] — A small space as between cracks, grooves, or ridges on 

various thalli. 
Ar'il — An exterior covering or fleshy organ around the hilum of a seed. 
As'co-carp [Gr. askos -(- karpos] — A fruiting body containing asci with ascospores. 
As'co-spore [Gr. askos + spores] — A spore produced in an ascus. 
As'cus [Gr. askos] — A sac-like body in which spores are produced, usually definite 

in number. 
As-sim'i-la'tion [L. assimilation] — In plants, the process by which dead, organic 

food materials are changed into the living protoplasm. 


At'a-vism [L. atavus] — A reversion to an ancestral type. 

At'a-vis'tic organ — One which shows in the individual a return to some ancestral 

At'ro-phied organ [Gr. atrophia] — An organ or part normal in the individual but 
which has become reduced thru pathological conditions or thru disuse. 

Ax'il — The point of a stem just above the base of the leaf. 

Awn — A slender bristle-like organ. 

Bac-te'ri-um [Gr. bakterion] — Any of the organisms belonging to the order Bac- 
teriales or even of the Schizomycetae. 

Ba-sid'i-o-spore' [Gr. basis + sporos] — A spore borne on a basidium. 

Ba-sid'i-um [Gr. basis] — A special form of sporophore characteristic of the Basid- 
iomycetae and related plants, typically bearing four basidiospores. 

Bast — The phloem of the vascular bundle, the inner bark. 

Bast fiber — Sclerenchymatous tissue in the bark of various plants. 

Bast pa-ren'chy-ma [Gr. paregchuma] — The soft thin-walled cellular tissue in the 

Bi-en'ni-al [L. biennalis] — Lasting for two seasons or two years. 

Bi-lat'er-al [L. bi -f- lateralis] — Having a similarity of parts on the right and left 
side, or on the two sides of a dividing plane. 

Bi-ol'o-gy [Gr. bios -f- logos] — The science of living organisms, including plants 
and animals. 

Bi-spo-ran'gi-ate [Gr. bi + sporos -f- ageion] — Having both microsporangia and 
megasporangia ; having both stamens and carpels. 

Biv'a-lent chromosomes [L. bis -f- valens] — Chromosomes formed during the reduc- 
tion division by the synapsis of two simple or univalent chromosomes. 

Bordered pits (of gymnosperms) — peculiar pits in the walls of the tracheids. 

Bot'a-ny [Gr. botane] — The science which treats of plants. 

Bract — A small, rudimentary, or imperfectly developed leaf. 

Brood bud — A vegetative reproductive bud or structure. 

Broken mother skein — A figure in nuclear division after the spirem has broken up 
into distinct chromosomes. 

Brownian movement [Pertaining to Robert Brown] — The peculiar, vibratory move- 
ment exhibited by microscopic particles when observed in water or other 
fluids under the microscope. 

Bud — A small structure on the end or the sides of a stem, which may develop into 
flowers or leafy shoots. 

Budding — In plants like the yeast, the process by which new cells are developed 
by the gradual formation of a protuberance from the mother cell. 

Bundle scar — A scar in a leaf scar produced by a vascular bundle. 

Bundle sheath (of vascular bundle) — A definite layer of cells completely or par- 
tially surrounding a vascular bundle. 

Ca-lyp'tra [Gr. kaluptra] — The hood or cap covering the sporangium (of a moss) 
and representing the enlarged archegonium. 

Ca-lyp'tro-gen [Gr. kaluptra -|- gignomai] — The layer of cells at the tip of a root 
from which the rootcap originates. 

Ca'lyx [Gr. kalux] — The outer set of sterile floral leaves; the whole set of sepals. 

Cam'bi-um [L. cambire] — The cylinder of growing cells in some stems. 

Cam'py-lot'ro-pous [Gr. kampulos -f- trope] — An ovule curved like a horseshoe. 

Cap'il-li'tium [L. capillus] — The mass of threads in the sporangium of a slime- 
mold or puffball. 


Cap'sule (of flowering plant) [L. capsula] — A dry fruit of two or more carpels, 

usually dehiscent by valves or teeth ; sometimes applied to the sporangium 

of a bryophyte. 
Car'pel [Gr. karpos] — The megasporophyll of a seed plant; the modified leaf or 

stem bearing the ovules. 
Car'pel-late — Having only carpels or carpellate flowers. 
Car-po-go'ni-um [Gr. karpos + gignesthai] — ■ Sometimes applied to the oogonium 

of the red algae. 
Car'po-spore [Gr. karpos -j- sporos] — A kind of spore produced in the cystocarps 

or sporocarps of the red algae. 
Car'po-stome [Gr. karpos -}- stoma] — The opening in the tip of a cystocarp. 
Cat'kin [Cat + kin] — The same as ament; a slender usually flexible spike of 

flowers as in the willows; (so called from its resemblance to a cat's tail). 
Cell [*L. cella] — The unit of plant and animal structure, usually consisting of a 

small mass of protoplasm, containing a nucleus and with a cell wall. 
Cell plate — The central disk or wall formed in the central spindle between the two 

daughter nuclei in cell division, which finally divides the cell into two 

daughter cells. 
Cel'lu-lose — The carbohydrate which constitutes the essential part of the ordinary 

cell wall of plants. 
Cen'o-cyte [Gr. koinos -j- kutos] — A mass of cells or protoplasts with a common 

limiting wall but without walls separating the individual cells, the several or 

numerous nuclei apparently inbedded indiscriminately in the cytoplasm. 
Cen'o-cyt'ic — Having the nature or structure of a cenocyte. 
Cen'tral spin'dle — The spindle of threads developed between the two sets of 

daughter chromosomes in nuclear division. 
Cen'tral strand (of mosses) — A strand of narrow, elongated cells in the center of 

a moss stem. 
Cen'tro-some [Gr. kentron -f- soma] — a minute body appearing beside the nucleus 

or at the poles of the spindle during cell division. 
Cen'tro-spere — Same as centrosome, but including the attraction-sphere around 

the central granule. 
Cha-la'zal [Gr. chalaza] — Pertaining to the base of an ovule. 
Chlam'yd-o-spore [Gr. chlamus -f- sporos] — A thick-walled, nonsexual spore as in 

the smuts. 
Chlo'ro-phyll [Gr. chloros -f- phullon] — The green coloring matter of plants. 
Chlo'ro-plast [Gr. chloros + plastos] — A minute green, chlorophyll-bearing color 

body in the cells of odinary plants. 
Chro'ma-tin granules [Gr. chromatos] — The granules in the chromatin which stain 

prominently with various dyes. 
Chro'ma-tin network — The network of threads with granules in the nucleus. 
Chro'ma-to-phore [Gr. chroma -f- pherein] — A splastid containing some coloring 

Chro'mo-plast ['Gr. chroma -f plastos] — A plastid containing some color other than 

Chro'mo-some [Gr. chroma -f soma] — One of the group of bodies formed from 

the chromatin network during karyokinesis. The chromosomes are con- 
sidered to be the special bearers of hereditary factors. 
Cil'i-a [L. cilium] — Slender protoplasmic lashes or projections, having the power 

of movement, extending from certain cells. 
Cir'ci-nate [L. circinatus] — Rolled inward from the apex. 


Class (of plants) — A group of plants in one of the seven subkingdoms or sub- 
series having an evident relationship to each other. 
Cla'vate [L. clava] — Club-shaped. 
Cleavage plane — A separation layer produced in leaves, stems, and other organs 

by means of which they are separated from the plant. 
Cleis'to-the'ci-um ['Gr. kleistos + theke] — An ascocarp in which the asci are com- 
pletely enclosed, the body having no ostiole. 
Close daughter skein — A figure produced by the chromatin during karyokinesis, in 

which the chromosome loops are more or less joined by connecting strands. 
Close mother skein — An early stage in karyokinesis when a continuous spirem is 

present which has not yet folded into definite loops nor broken apart. 
Col-len'chy-ma [Gr. Kolla + egchuma] — A tissue of plant cells which have the 

walls thickened at the angles. 
Coro-ny [L. colonia] — A group of unspecialized unicellular plants loosely con- 
nected in the vegetative phase. 
Col'u-meria [L. columella] — A column-like axis in a sporangium. 
Companion cells (in the bast) — Protoplasmic cells in and around the sieve tube 

tissue of the phloem. 
Com'pound leaf — A leaf composed of several divisions or leaflets, the blades of 

which are not continuous. 
Con-cen'tric vascular bundle [L. con -f- centrum] — A vascular bundle with the 

xylem in the center surrounded by phloem, as in certain ferns. 
Con-cep'ta-cle [L. conceptaculum] — A cavity, in a fruiting body, opening to the 

outside by an ostiole and containing either spermaries or ovaries, or both, 

as in the brown algae. 
Cone — A strobilus, a primitive flower as the carpellate cone of the pine. 
Co-nid'i-o-phore [Gr. konis + phoros] — A branch or organ which bears conidia. 
Co-nid'i-um [Gr. konis] — A nonsexual spore formed by the cutting off and 

specialization of cells from the tip of a conidiophore, or by division of 

fungal hyphae. 
Con'ju-ga'tion [L. conjugatio] — Specifically the union of similar gametes, but 

generally the union of egg and sperm in fertilization or the union of any 

two bodies as univalent chromosomes into bivalent ones. 
Con-tract'ile vac'u-ole [L. contractus vacuus] — A pulsaitng cavity in the interior 

of a protozoan supposed to be excretory in function. 
Cork — The suberized tissue produced in the outer bark by the cork cambium or 

Cork cambium — The tissue of dividing cells in the bark which produces the cork 

Co-rol'la [L. corolla] — The inner set of sterile, usually colored, floral leaves; the 

whole set of petals. 
Cor'tex [L. cortex] — The parenchymatous tissue in a young stem between the 

epidermis and the phloem. 
Cor'ti-cal — [L. cortex] — Pertaining to or consisting of the cortex. 
Cos'ta [L. costa] — The midrib of a moss scale. 

Cot'y-le'don [Gr. kotuledo'n] — A leaf-like organ of the embryo in the seed. 
Cross or transverse section — A section cut at right angles to the long axis of an 

organ as the stem. 
Crys'tal-loid (in aleurone grain) [Gr. krustallos] — A minute crystal-like particle 

present in some aleurone grains. 


Cu'ti-cle [L. cuticula] — The outermost tissue of cells, usually one layer thick, in 
the higher multicellular plants. The cuticle is often destroyed at an early 
stage as in dicotyl woody stems. 

Cy'clic [Gr. kuklos] — Having the floral organs arranged in cycles or whorls. 

Cys'to-carp [Gr. kustis + karpos] — A form of sporocarp produced in the red algae, 
having the carpospores surrounded by a thickened envelope. 

Cys'to-lith [Gr. kustis -\- lithos] — A concretion of calcium carbonate deposited in 
certain plant cells, usually on a projection from the cell wall. 

Cy-tol'o-gy [Gr. kutos + logos] — The branch of biology which deals with the struc- 
ture, functions, and activities of the cell and its various protoplasmic organs. 

Cy'to-plasm [Gr. kutos + plasma] — The more fluid part of the protoplasm ex- 
clusive of the nucleus and plastids. 

Daughter cell — A cell which has been derived from the division of a mother cell. 

Daughter stars — The karyokinetic figure in the anaphase when the daughter 
chromosomes are approaching the poles. 

De-cid'u-ous [L. deciduus] — Falling away at the end of the growing period by a 
separation layer or cleavage-plane. 

De-fin'i-tive nucleus (cell) [L. definitivus] — The nucleus which is formed in the 
female gametophyte of the anthophyta by the conjugation of the polar cells 
(usually two) and which gives rise to the endosperm, frequently after having 
conjugated with a sperm nucleus. 

Der-mat'o-gen [Gr. derma -J- gignomai] — The embryonic tissue from which the 
epidermis is produced. Incipient epidermis. 

Di-chot'o-mous [Gr. dichotomos] — Once or several times two-forked. 

Di-cot'yl [Gr. di -j- kotule] — A plant belonging to the class of Dicotylse, or having 
two cotyledons. 

Di-e'cious [Gr. di -f- oikos] — Having the microsporangiate or staminate flowers 
and the. megasporangiate or carpellate flowers on separate plants. 

Disk flower — One of the tubular flowers in such inflorescences as are present in 
the sunflowers and related plants. 

Dis-sem'i-na'tion [L. disseminatio] — The act of scattering seed. 

Dom'i-nant character [L. dominans] — A character possessed by one of the parents 
of a hybrid, which appears in the hybrid and prevents the corresponding 
recessive character from the other parent from developing so long as their 
factors are associated. 

Dor'sal [L. dorsualis] — Pertaining to the back. 

Dor'si-ven'tral [L. dorsum + venter] — Having a distinctly differentiated upper 
and lower surface or part, usually lying flat on the substratum. 

Drupe [Gr. druppa] — A simple, usually indehiscent fruit with fleshy exocarp and 
bony endocarp. 

Du-ra'men [L. durare] — The heart wood of a tree or shrub. 

Dwarf branch — A highly specialized and reduced shoot bearing leaves, as in the 
pine and larch. 

Dwarf male — A very small male plant produced in some algae like CEdogonium. 

Early wood — The first, often porous, wood of the annual ring produced by the 
cambium in the spring. Sometimes called spring wood. 

E-col'o-gy [Gr. oikos -+- logos] — The study of all the relations of plants associated 
and grouped together under definite conditions of life, or of the individual 
and its structures as related to or influenced by the environment. 

Egg — The female reproductive cell or gamete. 


Egg-apparatus — The two synergids and the egg or oosphere present in the tip of 
the angiosperm female gametophyte. 

E-la'ter [L. elatus] — An organ in the sporangium for opening the wall and aiding- 
in scattering the spores. 

E-mar'gi-nate [L. emarginare] — With a notched apex. 

Em'bry-o [Gr. embruon] — An incipient plant. In the seed plants the term is 
usually restricted to the young sporophyte in the seed. After sprouting it is 
a seedling or juvenile individual. 

Em'bry-o sac (sack) [L. saccus, Gr. sakkos] — The female gametophyte, contained 
in the ovule of seed plants. 

Em-bry-on'ic — Pertaining to an embryo. 

Emp'ty glume — One of the two glumes at the base of a grass spikelet. 

En'do-carp [Gr. endon -f- karpos] — The inner layer of the pericarp. 

En-do-der'mis [Gr. endon + derma] — A limiting layer of cells inside of the cortical 
tissue, often separating the parenchymatous from the vascular tissue; in 
many monocotyls dividing the stem into a central and outer portion. 

En-do-phyt'ic [Gr. endon -f- phuton] — Applied to a plant growing within another 
plant on which it may or may not be parasitic. 

En'do-sperm [Gr. endon -j- sperma] — The nutritive tissue developed around the 
embryo in the female gametophyte of angiosperms. It is developed from 
the definitive nucleus and typically has the triploid (3x) number of chro- 

En-to-moph'i-lous [Gr. entomon + philos] — Said of plants in which pollination is 
accomplished by the agency of insects. 

En-vi'ron-ment — The external conditions and influences surrounding the living- 
organism. The influence may be inside of the organism or even inside of 
the cell. 

Ep'i -der'mis [Gr. epi -f- derma] — The external layer of cells in plants. 

E-pig'y-nous [Gr. epi -f- gune] — Having the calyx, corolla and andrecium above 
the ovulary. 

E-qua-to'ri-al plane [>L. aequator] — The central plane of the cell, cutting the cell at 
right angles to the direction of the nuclear division. 

Eu-spo-ran'gi-ate [Gr. eu -f- sporos + aggeion] — Having the essential part of the 
sporangium produced from the sub-epidermal cells. 

Ev-a-nes'cent [L. evanescens] — Disappearing early 

Ev-o-lu'tion (organic) [L. evolutio] — The process by which the members of the 
organic kingdom have developed thru descent from each other. Evolution 
in general tends from the undifferentiated to the specialized; from the 
simple to the complex ; from the low to the high ; but the tendency may also 
be in the opposite direction, resulting in a simplification of the complex or a 
degeneration of the functional parts. 

Ex'o-carp [Gr. exo -f- karpos] — The outer layer of the pericarp. 

Eye'spot — A small body containing pigment usually of a reddish color, present in 
many unicellular plants and animals and especially in zoospores. It is 
supposed to be sensitive to light. 

Fam'i-ly (of plants) [L. familia] — A group of related plants, comprising one or 
more genera and ranking below the order. 

Fe'male — Any plant which produces directly (either following a reduction division 
or not) eggs or female gametes. 

Fe'male gam'ete [Gr. gamete] — The egg cell or oosphere. 

Fern — Any plant belonging to the class Filices. 


Jrer'tile [L. fertilis] — Applied to a plant or part which produces normal spores, 
pollen, seeds, eggs, or sperms. 

Fer'ti-li-za'tion [L. fertilis] — In botany, the union of the two gametes ; the con- 
jugation of the egg and sperm. 

Fil'a-ment [L. filumj — A thread-like plant body as in the algse and fungi ; in the 
flowering plants, the slender stalk of the stamen below the anther. 

Fla-gel'lum [L. Flagellum] — A long whip-like protoplasmic mobile process, pro- 
jecting from certain cells, especially zoospores and spermatozoids. 

-Flo'ral organ [L. floralis] — The organs of a flower, mainly sepals, petals, stamens, 
and carpels. 

-Flow'er [L. flos] — The modified spore-bearing shoot or branch of the antho- 
phyta; the various types of strobili or cones of the Calamophyta (Lepido- 
phyta, Cycadophyta and Strobilophyta are primitive flowers to which the 
term may be applied in a general way.) 

J?low'er-ing glumes [L. flos, gluma] — The two chaffy bracts enclosing the grass 

Fluc-tu-a'tion [L. fluctuatio] — A variation due to the direct effect of the environ- 
ment during the life time of the individual. 

Fo-li-a'ceous [L. foliaceus] — Belonging to a leaf; leaf-like. 

Toliage leaf — A normal green leaf. 

Foot (of sporophyte) — The basal part of the sporophyte of a liverwort or moss; 
the absorbing organ of a pteridophyte embryo. 

F>ond [L. frons] — A large or highly developed thallus or gametophyte. Some- 
times wrongly applied, to fern leaves. 

Fruit [L. fructus] — The spore-bearing parts of seedless plants; but especially in 
the seed plants the ripe carpels or ovulary with the seeds and whatever 
parts are modified or consolidated with these organs. 

Fun'gus [L. fungus] — Any thallophyte without chlorophyll. 

Fu-nic'u-lus [L. funiculus] — The little stalk by which the ovule or seed is attached 
to the placenta. 

'Gam'e-tan'gi-um [Gr. Gamete or gametes + aggeion] — An organ which produces 

Gam'ete [Gr. gamein] — A sexual cell; an egg, sperm, or isogamete. 

Ga-me'to-phore [Gr. gamete or gametes -\- pherein] — A branch which bears sexual 

Ga-me'to-phyte [Gr. gamete or gametes + phuton] — The sexual generation of 

Gem'ma [L. gemma] — A brood-bud capable of reproducing the plant. 

Gen'er-a-tive cell [L. generatus] — Sometimes applied to the sperm mother cell in 
the pollengrain of Anthophyta. This cell by division, either in the pollen- 
grain or in the pollentube, gives rise to two sperms. 

Ge'nus [L. genus, Gr. genos] — A group of plants of lower rank than the family. 
The generic name constitutes the first of the two words in the binomial 
name of a species. 

Ge-oph'i-lous [Gr. ge -J- philein] — Earth-loving; growing under the ground, as 
under-ground stems. 

Ge-ot'ro-pism [Gr. ge -f- trepein] — The tendency of roots or other plant organs to 
assume growth curvatures under the influence of gravity. 

Ger'mi-na'tion [L. germinatus] — The division or budding of a spore or reproduc- 
tive cell; the beginning of the growth of a new individual plant. 


Gills' [of toadstools] — The spore-bearing plates or lamellae on the pileus of one- 

of the Agaricaceae. 
Gir'dle view — The side of a diatom where the two valves overlap. 
Glo'boid [L. globus] — A small globular body often found in aleurone grains. 
Glume [L. gluma] — The scaly bracts of the flowers and spikelets of grasses and 

Grain [L. granum] — Any minute particle; the seed-like fruit of plants belong 

to the grass family. 
Ground tissue — The general pith-like tissue in a stem thru which the vascular 

bundles and sclerenchyma bundles pass as in the fern stem. 
Guard cells — The bordering cells on either side of a stoma. 

Gym'no-sperm [Gr. gumnos -f- sperma] — A plant having naked seeds; a plant be- 
longing to the subkingdom Gymnospermae. 
Gy-ne'ci-um [Gr. gune -f- oikos] — The whole set of carpels in a flower. 
Hab'i-tat [L. habitare] — The place where a plant grows. 
Haem'a-to-chrome [Gr. haima -\- chroma] — A red coloring matter in some algae as 

in Sphaerella. 
Haus-to'ri-um [L. haurire] — In parasitic plants, a specialized outgrowth from the 

stem or mycelium serving as an organ of absorption. 
Heart'wood — The hard, central part of a woody stem, usually differing in color 

from the younger outer sapwood. It is called duramen. 
He'li-ot'ro-pism [Gr. helios -\- trepein] — Same as phototropism. 
He'lot-ism [Gr. heilos] — The condition of symbiosis in which one of the sym- 

bionts, altho obtaining food from the other and giving none in return, causes. 

no special injury as in the relation between alga and fungus in a lichen. 
Her-ba'ceous [L. herbaceus] — Leaf-like in texture and color.; having the charac- 
teristics of an herb. 
Her-ba'ri-um [L. herba] — A collection of dried specimens of plants systematically 

He-red'i-ta-ry [iL. hereditarius] — Capable of descending or of being transmitted 

from parent to offspring. 
Hereditary character — Any structure or peculiarity developed in an individual as 

the result of the normal activity of one or more hereditary factors. 
Hereditary factor — The property or ability possessed by a cell thru the activity of 

which an hereditary character is developed, either independently by its own 

activity or in connection with other properties or factors. 
He-red'i-ty [L. hereditas] — The biological principle or law in accordance with 

which an organism transmits its qualities and characteristics to its offspring. 

The ability of an organism to transmit its peculiarities to its offsprng. 
Her-maph'ro-dite [Gr. hermaphroditos] — An individual having both male and 

female sex organs. , 
Het-er-e-cism [Gr. heteros -\- oikia] — The condition in which a parasite passes thru 

different stages of its life history on an alternation of hosts. 
Het'er-o-cyst [Gr. heteros -f kustis] — A large special type of cell occurring in the 

filaments of certain blue-green algae. 
Het-er-os'por-ous [Gr. heteros -f- sporos] — Having two kinds of spores ; having 

megaspores and microspores. 
His-to-log'ic-al [Gr. histos -f- logos] — Pertaining to the cellular structure of the 

Hold'fast — A disk-like or branching body by means of which certain algae are 

attached to the substratum or support. 


Ho'lo-phyte [Gr. holos + phuton] — A plant which produces all of its food from 

inorganic substances. 
Ho-mol'o-gous organs [Gr. homologos] — Organs or parts similar in origin and 

Ho-mos'por-ous [Gr. homos + sporos] — Having only one kind of spores on the 

sporophyte generation. 
Hor'mo-gone [Gr. hormos -J- goneia] — A chain of cells in certain algae separated 

from the parent body and by which the plant is propagated. 
Host [L. hostis] — The plant or animal on which a parasite lives. 
Hy'a-line [Gr. hualinos] — Clear and translucent. 
Hy'brid [L. hybrida] — The offspring of two parents which differ in one or more 

hereditary factors or characters, especially the offspring of parents from 

different races, varieties or species. 
Hy'dro-phyte [Gr. hudor -)- phuton] — A water plant, or one growing in very wet 

Hy'gro-scop'ic [Gr. hugros -\- skopein] — Readily absorbing and giving off water, 

by which movements are produced. 
Hy-me'ni-um ['Gr. humenl — The spore-bearing surface of certain fungi. 
Hy-pan'thi-um [Gr. hupo -(- anthos] — Any enlargement or special development of 

the torus, in a flower, on which the sepals, petals, and stamens are borne ; a 

perigynous disk. 
Hy'pha [Gr. huphe] — A branch or part of a filament of a fungus mycelium. 
Hy'po-cot'yl [Gr. hupo -j- kotule] — That portion of the stem below the cotyledons 

in the embryo of a seed plant. 
Hyp'o-der'mal [Gr. hupo + derma] — Pertaining to the tissue or parts beneath the 

Hy-pog'y-nous [Gr. hupo -f- gune] — Having the calyx, corolla, and andrecium 

below the gynecium. 
Hy-poph'y-sis [Gr. hupo + phusisj — The expansion or part just below the 

sporangium of a moss, often with stomata. 
Hy-po-thal'lus [Gr. hupo -f- thallos] — A fleshy or membranous base bearing spor- 
In'cept, in-cip'i-ent [L. incipere] — An organ or part in its first stages of develop- 
ment in the individual, or in its embryonic condition. 
In-du'si-um [L. indusium] — The membranous covering of the sori in many species 

of ferns. 
In-flo-res'cence [L. inflorescens] — The flower cluster of a plant and its mode of 

In-her'it-ance [L. inhereditare] — The act or state of transmitting hereditary fac- 
tors from one generation to another. The set of hereditary factors 

possessed by an organism which is or may be transmitted. 
In-i'tial cell [L. initialis] — The original cell from which a tissue is developed. 
In'ner bark — The tissue between the stelar cambinum and the cork cambium. 
In-teg'u-ment (of ovule) [L. integumentum] — One or two covering envelopes 

which invest the ovule and later become seed coats. 
In'ter-cel'lu-lar spaces — The cavities between adjoining cells. 
In'ter-node [L. internodium] — Part of a stem between two successive nodes. 
In'vo-lu'cre [L. involucrum] — A whorl of bracts subtending a flower or flower 



I'so-bi-lat'er-al ['Gr. isos + L. bilateralis] — A flower or organ which can be cut 
into equal halves by two planes, the halves of the one being unlike those of 
the other. 

I'so-carp'ic [Gr. isos -j- karpos] — Having as many carpels in a set as there are 
petals, or sepals. 

I-sog'am-ous [Gr. isos + gamos] — Having gametes of equal size and appearance. 

I-so-gam'ete [Gr. isos + gamete] — One of a pair of equal gametes. 

Ju've-nile organ [L. juvenilis] — An organ which is normal and functional in the 
early stages of the individual but which later disappears, as the juvenile 
leaves of certain seedlings. 

Kar'y-o-ki-ne'sis [Gr. karuon -)- kinein] — The process of indirect nuclear division. 

Lac-tif'er-ous duct [L. lac + ferre] — Ducts present in some plants containing a 
milky sap or latex. 

La-mel'la [L. lamella] — One of the gills of a toadstool; a thin plate or layer as 
the middle lamella of certain thick cell walls. 

Lam'i-na [L. lamina] — The blade of a leaf. 

Late wood — The part of the annual ring of wood produced at the latter end 
of the growing season. 

Latex [L. latex] — The milky sap of certain plants. 

Leaf — An expansion arising from the axis or branch of a sporophyte, usually 
specialized to carry on the functions of photosynthesis and transpiration. 

Leaflet — One of the divisions of a compound leaf. 

Leaf scar — The scar or cicatrix formed where the petiole of a leaf separates from 
the stem or twig. 

Leaf trace — One or more vascular bundles which may be traced down from the 
base of the leaf into the stem, continuing distinct for some time before 
uniting with the stele. 

Lem'ma [Gr. lemma] — The outer of the two flowering glumes inclosing a grass 

Len'ti-cel [L. lens, lentis] — A small, usually oval or round spot on the bark of a 
twig or stem, produced by a special tissue of cells under a stoma and break- 
ing thru the epidermis. 

Lep'to-spo-ran'gi-ate [Gr. leptos' + sporos + aggeion] — Having the sporangia de- 
veloped from superficial cells. 

Leu'co-plast [Gr. leukos + plastos] — A colorless plastid. 

Li'chen [Gr. leichen] — A lichen is a plant structure formed by the association of a 
fungus and numerous algae, forming a rather definite appearance which 
simulates an individual. The lichen fungus is a slave-holder, living sym- 
botically with the algae as slaves. By some the word "lichen" is restricted 
to the fungus part alone, but as here defined, the lichen fungus is regarded 
as a true fungus and the peculiar appearance or body, which is readily 
recognized in typical forms, — caused by the symbiosis of the two organisms, 
— is called the "lichen." 

Lid cells (of archegonium) — The cells at the tip of the neck of an archegonium 
which open up to permit of the entrance of the sperms. 

Life cy'cle — The succession of stages in the life history of an organism from its 
beginning in the fertilized egg or spore until it reproduces cells of a corre- 
sponding nature. 

Life history — The succession of stages in the life of an organism from its 
beginning- until it disappears thru natural death or by division gives rise to a 
new organism similar to itself. 


Lig'nin [L. lignum] — The chemical substance composing the walls of woody cells. 
Lig'u-late [L. ligula] — Provided with or resembling a ligule ; as a ligulate flower. 
Lig'ule — A strap-shaped organ ; a triangular or somewhat elongated stipule-like 

organ on the leaves of Isoetes and Selaginella. 
Limb — The expanded part of a petal, sepal, or sympetalous corolla. 
Li'nin [L. linum] — The substance of the achromatic network or spirem on which. 

the chromatin granules are held. 
Lip cells (of fern sporangium) — Specialized cells where the sporangium will break 

Lip'o-chrome [Gr. lipos -j- chroma] — Any of several pigments usually yellow, 

orange, or yellowish-red, nonsoluble in water, found in various plants. 
Liv'er-wort — Any plant belonging to the class Hepatioas. 
Lod'i-cule [L. lodicula] — One of the two or three minute hyaline scales in the 

flowers of grasses, representing a vestigial perianth. 
Lon'gi-tu'di-nal [L. longitudo] — Extending in the direction of the length. 
Looped mother skein — The stage in karyokinesis in which the spirem is arranged 

in definite loops just before it breaks in pieces. 
Loose daughter skein — The stage in karyokinesis in which the separate daughter 

chromosomes are beginning to unite, after the daughter star. 
Lu'men [L. lumen] — The cavity of a tubular cell; a passage within the walls. 
Ly-si'ge-nous cavity [Gr. lusis + genesis] — An intercellular space formed by the 

breaking down or dissolution of adjoining cells. 
Male — An individual that produces spermatozoids but not oospheres directly from 

the cells of its own body. 
Male gamete — The spermatozoid or sperm. 
Marfor-ma'tion [L. malus -f- formatio] — Such organs or parts as show abnormal 

growths due directly to some external condition in the life of the individual, 

as a bud developed into an insect gall. 
Med'ul-la'ry ray [L. medullaris] — A strip of cells passing radially thru the wood 

from the pith or the various annual rings to the bark. 
Meg'a-spo-ran'gi-um [Gr. megas -f- sporos + aggeion] — A sparangium which pro- 
duces megaspores; the ovule in seed plants. 
Meg'a-spore [Gr. megas -j- sporos] — The larger of the two kinds of nonsexual 

spores produced in heterosporous plants. The megaspore develops into the 

female gametophyte. 
Meg'a-spo'ro-cyte [Gr. megas -\- sporos + kutos] — One of the cells in the 

megasporangium in which the reduction division takes place and which 

normally gives rise to four megaspores. 
Meg'a-spo'ro-phyll [Gr. megas -j- sporos -f- phullon] — The modified leaf which 

bears the megasporangia. In seed plants usually called a carpel. 
Mer'i-stem [Gr. merizein] — A tissue of dividing cells; embryonic tissue. 
Mer'i-ste-mat'ic [Gr. merizein] — Pertaining to the meristem or dividing tissue.. 
Mes'o-phyll [Gr. mesos -f- phullon] — The parenchymatous tissue in a leaf between 

the upper and lower epidermis. 
Mes'o-phyte [Gr. mesos + phuton] — A land plant growing in ordinary conditions 

of moisture. 
Met'a-ki-ne'sis [Gr. meta + kinesis] — The stage in nuclear division after the 

formation of the mother star. 
Met'a-phase [Gr. meta -f- phasis] — The second general stage in karyokinesis in 

which the individual chromosomes pass from a scattered condition in the 

nuclear cavity to a definitely arranged mother star in the equatorial plane- 


Mi'cro-pyle ['Gr. mikros -f- pule] — The small opening or pore at the outer end of 
the ovule where the integuments come together over the nucellus. 

Mi'cro-spo-ran'gi-um. [Gr. mikros -f- sporos -J- aggeion] — A sporangium which 
produces microspores ; the pollensacks in seed plants. 

JVIi'cro-spore [Gr. mikros -f- sporos] — The smaller of the two kinds of nonsexual 
spores produced in heterosporous plants. The miscopore develops into the 
male gametophyte, called a pollen grain in seed plants. 

JVli'cro-spo'ro-cyte [Gr. mikros + sporos -|- kutos] — One of the cells in the mi- 
crosporangium in which the reduction takes place and which usually gives 
rise to four microspores. 

Mi'cro-spo'ro-phyll [Gr. mikros -f- sporos + phullon] — The modified leaf which 
bears the microsporangia. In seed plants usually called a stamen. 

Mid'rib — The central rib of a leaf or other organ. 

Mil'dew — Any of the mold-like parasitic fungi, as the downy mildews and 
powdery mildews. 

Mi-to'sis [Gr. mi'tos] — Indirect nuclear division. Same as karyokinesis. 

Mold — Any of the saprophytic fungi consisting of loose hyphae, as the common 
bread mold and the common blue mold. 

Mo-ne'cious [Gr. monos -\- oikia] — Having staminate and carpellate flowers on 
the same plant. 

Mon'o-cot'yl [Gr. mo'nos + kotule] — A plant having one cotyledon. 

Mon'o-po'di-al [Gr. monos -}- pous] — having a single and continuous axis, as a 
twig which grows from a persistent terminal bud. 

Mon'o-spo-ran'gi-ate [Gr. monos + sporos -\- aggeion] — Having only one kind of 
spores in the flower ; a flower with only stamens or carpels. 

Mor-pho-log'ic-al [Gr. morphe -f- logos] — Of or pertaining to the form and struc- 
ture of an organ. 

Moss- — Any of the bryophytes except the liverworts and hornworts, as the bog- 
mosses, granite-mosses and true mosses. 

Mother cell — A cell which divides into two daughter cells ; or the parent cell of 

two cells. 

Mother star — The star-like figure appearing in karyokinesis when the chromosomes 
are in the equatorial plane. 

Mul'ti-cel'lu-lar [L. multus -f- cella] — Composed of more than one cell. 

Mush'room — Any large fungus belonging to the Ascomycetse or Basidiomycetae, 
whether edible or poisonous, fleshy or otherwise. 

Mu-ta'tion [L. mutatio] — A variaton due to the presence of a specific hereditary 
factor or set of factors in the organism inherited in a definite way. A sud- 
den variation as distinguished from a gradual variation, the offspring differ- 
ing from the parents in some well-marked hereditary character or characters. 

Mu'tu-al-ism [L. mutuus] — The condition of symbiosis in which each of the 
symbionts is of benefit in obtaining the food supply. 

My-cel'li-um [Gr. mukes] — The entire mass of hyphae or threads which make up 
the body of a fungus. 

My-co rhi'za [Gr. mukes -|- hriza] — The mutualistic, symbiotic association of a 
fungus mycelium with the roots or other underground parts of a plant. 

Nas'cent organ [L. nascens] — An organ or part at the beginning of its evolution 
or at the beginning of its development in the race; or in its first stages of 
evolution as compared with other homologous organs. 

Neck (of archegonium) — The upper part of an archegonium thru which the 
sperms enter to unite with the egg. 


Neck canal (of archegonium) — The passage, or row of central cells in the neck 
of an archegonium. 

Nec'tar gland [Gr. nektar] — A gland which secretes nectar. 

Nec'tary — A nectar-secreting organ. 

Node [L. nodus] — The place where two internodes join, normally with a single 
leaf or more. 

Non-sex'u-al [iL. non -f- sexus] — Being without sex ; not producing gametes but 
spores which develop without conjugation. 

Nu-celTus [L. dim. of nux] — The incipient ovule, or the outer end of the ovule 
exclusive of the integuments. 

Nu'cle-ar membrane [L. nucleus] — The layer of protoplasmic material surround- 
ing the nucleus. 

Nu'cle-us [L. dim. from nux] — The dense, more or less spherical, complex, proto- 
plasmic body present in the cell. 

Nu-cle'o-lus [L. dim. of nucleus] — A small rounded body contained in the 
nucleus ; one or more may be present. 

On-tog'e-ny [Gr. on, ontos -j- gignomai] — The history of the development of the 
individual organism; the development of the individual. 

O'o-go'ni-um [Gr. oon + gonos] — A simple ovary, usually consisting of a single- 
cell containing one or more eggs. 

O'o-sphere [Gr. oon -f- sphaira] — The unfertilized egg; the female gamete. 

O'o-spore [Gr. oon -J- sporos] — The fertilized egg. 

O-per'cu-lum [L. operculum] — The lid at the tip of the sporangium of a moss or 
other plant. 

Or'der [L. ordo] — A group of plants consisting of one or more families; the 
first general group of lower rank than the class. 

Or'gan [Gr. organon] — A part or structure of a plant fitted for the performance 
of a definite function or set of functions. 

Or-thot'ro-pous [Gr. orthos -j- trepein] — A straight ovule, having the hilum and 
micropyle at opposite ends. 

Os-mo'sis [Gr. osmos] — Diffusion thru membranes or partitions. The specific 
relation which exists between solutions and the material of the separating, 
membrane, determining variable selection and permeability. 

Os'ti-ole [L. ostiolum] — The orifice opening into the cavity of a conceptacle, peri- 
thecium, or similar structure. 

Outer bark — The rough corky tissue developed from the cork cambiums outside 
of the inner bark which is developed from the stelar cambium. 

O'va-ry [L. ovum] — The female organ of reproduction; an egg-producing organ. 

O'vu-la'ry [L. ovum] — The ovule-bearing part of a closed carpel or set of carpels. 

O'vule [L. ovum] — The megasporangium of a seed plant which later develops into 
a seed. 

O'vu-lif'er-ous scale [L. ovum -J- ferre] — The peculiar outgrowth from the carpels, 
of some conifers at the base of which the ovules are borne. 

Pa'let [L. palea] — The inner of the two glumes inclosing the flower of a grass. 

Pal'i-sade pa-ren'chy-ma [L. palus. Gr. paregchuma] — The tissue of vertically 
elongated cells in the upper side of a leaf below the epidermis. 

Pan'i-cle [L. panicula] — A compound inflorescence of the racemose type usually of 
pyramidal form. 

Pap'pus [Gr. pappos] — The bristles, awns, teeth, etc., on the top of an achene.. 
representing a calyx, or having the position of a superior calyx. 


Par'a-site [Gr. parasitos] — An organism growing upon other living plants or ani- 
mals and absorbing their juices and tissues as food and thus causing them 

Pa-raph'y-sis [Gr. para-f- phusis] — A hair or hair-like scale growing among the 
reproductive organs. 

Pa-ren'chy-ma [Gr. paregchuma] — A fundamental plant tissue usually composed 
of thin-walled cubical or polygonal cells rich in protoplasmic contents. 

Par'the-no-gen'e-sis [Gr. parthenos -j- gignomai] — The germination and develop- 
ment of an egg or other gamete without being fertilized or uniting with 
another gamete. 

Pel'tate [Gr. pelte] — Shield-shaped, as a leaf with the petiole attached at or near 
the center of the blade. 

Pen'ta-cy'clic [Gr. pente -+- kuklos] — Having five cycles^ 

Pen-tam'er-ous [Gr. pente -f- meros] — Five parted. 

Per-en'ni-al [L. perennis] — Growing for more than two years or for many years. 

Per'i-anth [Gr. peri -f- anthos] — The calyx and corolla taken collectively; the 
floral leaves taken collectively when not differentiated into calyx and corolla. 

Per'i-blem [Gr. periblema] — The layer of meristematic tissue lying between the 
dermatogen and the plerome. 

Per'i-carp [Gr. peri -f- karpos] — The wall of a fruit; the ovulary wall. 

Per'i-derm [Gr. peri -\- derma] — The corky tissue of the outer bark derived from 
growth of the phellogen. 

Pe-rid'i-um [Gr. peridion] — The wall of a spore case in various fungi, or the wall 
of the fruiting body as in a puffball. 

Per'i-gyn'i-um [Gr. peri -f- gume] — The sack-like envelope surrounding the arche- 
gonia in liverworts. The sack-like envelope around the ovulary of a Carex 

Pe-rig'y-nous [Gr. peri -j- gune] — Having the sepals, petals, and stamens borne on 
a disk or hypanthium surrounding the gynecium. 

Per'i-stome (of a moss) [Gr. peri -J- stoma] — The fringe of teeth surrounding 
the mouth of a moss sporangium when the operculum is removed. 

Per-i-the-ci-um [Gr. peri -j- theke] — A flask-shaped body with an ostiole contain- 
ing asci; a certain kind of ascocarp. 

Pet'al [Gr. petalon] — One of the leaves or segments of the corolla. 

Pet'i-ole [L. petiolus] — The stalk of a leaf. 

Phag'o-phyte [Gr. phagein -\- phuton] — A plant which is able to take up organic 
food either as a parasite or saprophyte. 

Phel'lo-derm [Gr. phellos + derma] — A secondary cortical tissue developed on 
the inside of and from the phellogen. 

Phel'lo-gen [Gr. phellos + genes] — The cork cambium ; a secondary meristem 
giving rise externally to cork tissue, and internally to secondary cortex or 

Phlo'em [Gr. phloos] — The part of the vascular bundle containing the sievetubes 
and their companion cells ; in a dicotyl the phloem forms part of the inner 

Pho-to-syn'the-sis [Gr. phos -f- sunthesis] — The process of constructive meta- 
bolism by which carbohydrates are formed from water and carbon dioxide 
in the chlorophyll-containing cells of plants exposed to the action of light. 

Pho-tot'ro-pism [Gr. phos -f- trepein] — The response of plants to light, leading to 
changes in growth and position [heliotropism]. 

Phy-co-cy'an [Gr. phukos + kuanos] — A blue coloring matter found in the blue- 
green algae. 


Phy-log'e-ny [Gr. phulon -j- gignesthai] — The history of the development of the 
race or phylum to which an organism belongs, in distinction from ontogeny. 

P'hy'lum (of plants) [Gr. phulon] — One of the great or fundamental natural 
groups of plants. The plant kingdom can be divided into fifteen phyla. 

Phys'i-o-log'ic-al [Gr. phusis -j- logos] — Pertaining to the functions and activities 
of organisms. 

Pi'le-us [L. pileus] — The expanded upper portion or cap of many of the fungi. 

Pi-lif'er-ous layer [L. pilus -f- ferre] — The external layer of cells in a young 
root, giving rise to the root hairs ; the epidermis of a root from which root 
hairs develop. 

Pith — The soft parenchymatous tissue in the center of a stem; the general ground 
tissue thru which scattered vascular bundles pass. 

Plank'ton [Gr. plagkton] — The minute free floating or swimming plants and ani- 
mals of a body of water; the secondary plankton includes the larger surface 
floating plants and also such as are commonly torn loose and float in the 

Plan'o-gam'ete [Gr. pianos + gamein] — A motile gamete. 

Plas-mo'di-um [Gr. plasma] — A jelly-like mass of fused naked, ameboid cells, as 
the Plasmodium of a myxomcete. 

Plas-mol'y-sis [Gr. plasma + lusis] — The contraction or shrinkage of the proto- 
plasm in a living cell due to the rapid loss of water by exosmosis. 

Plas'tid [Gr. plastis] — One of the small granules or color bodies found in the 
cytoplasm of plant cell. They are divided into chloroplasts, chromoplasts 
and leucoplasts. 

Ple'rome [Gr. pleroma] — The central cylinder or column of tissue in an em- 
bryonic plant. 

Plu'mule [L. plumula] — The bud or growing point of an embryo plant in the seed. 

Plu'ri-loc'u-lar [L. plus, pluris + loculus] — Having several cavities or loculi; in 
algae, having many cells separated by walls = multicellular, as plurilocular 

Po'lar nu'cle-i — The two free nuclei present in most female gametophytes of the 
Anthophyta which together with a spermatozoid conjugate to form the 
definitive nucleus which gives rise to the endosperm of the seed. 

Po'lar ra'di-a'tions — The radiations which surround the poles of the spindle during 
karyokinesis and later, near the end of nunclear division, the daughter nuclei. 

Poles of spin'dle — The two points in the karyokinetic figure to which the spindle 
fibers converge, and often surrounded by radiations. 

Pol'len [L. pollen] — The mass of male gametophytes of seed plants. 

Pol'len cham'ber — The cavity in the tip of the ovule of certain lower gymnosperms, 
into which the pollen is received after passing thru the micropyle. 

Pol'len grain — The male gametophyte of seed plants. 

Pol'len sac (sack) — A cavity in an anther containing pollen ; the microsporangium 
of a seed plant after the microspores have germinated. 

Pollen tube — The tubular outgrowth which develops from the pollengrain and 
penetrates into the ovule. The male gametes or sperms pass thru this tube 
and enter the female gametophyte. 

Pol'li-na'tion — The transfer of the pollen, or male gametophytes, to the stigma or 
to the micropyle of the ovule. 

Pol'y-stelic — [Gr. polus -(- stele] — Having several steles. 

Pri'ma-ry cor'tex — The periblem or the tissue derived directly from it; the tissue 
in the stem between the vascular bundles and the epidermis. 


Pri-mor'di-um [L. primordius] — A nascent organ; an organ in its first stages of 

evolution as compared with other similar organs. 
Pro-cam'bi-um [L. pro — |- cambire] — The young tissue of a vascular bundle before 

its cells have begun to be differentiated, or the tissue from which the original 

vascular bundles are developed. 
Pro-em'bry-o [Gr. pro' -j- embruon] — The early embryo before its differentiation. 

It is usually differentiated into a suspensor and the embryo proper. 
Pro-my-ce'li-um — [Gr. pro -f- mukes] — The short hyphal filament or basidium 

produced by a germinating chlamydospore, as in the rusts and smuts. 
Pro'phase [Gr. pro' + phasis] — The first genearl stage in karyokinesis in which 

the chromatin network is transformed into a spirem and thrown into loops. 
Pro'to-ne'ma [Gr. protos -J- nema] — The filamentous green alga-like body or em- 
bryonic thread, which develops from the spores of certain ferns and 

bryophytes or from some part of a moss plant. 
Pro'to-plasm [Gr. protos + plasma] — The living substance found in the cells of 

plants and animals. 
Pro'to-plas'mic con'ti-nu'i-ty — Having the protoplasts connected by protoplasmic 

strands which pass thru the cell wall. 
Pro'to-plast [Gr. protos -f- plastis] — The protoplasmic cell contents, exclusive of 

the cellulose wall. 
Pro'to-ste'le [Gr. protos + stele] — The solid stele characteristic of most roots, of 

the earliest portions of stems and in some petriodophytes of the whole of 

the axis. 
Pseu'do-po'di-um [Gr. pseudes -|- pous] — A scaleless branch of a moss bearing 

gemmae or a sessile sporangium. 
Puff 'ball — Any fungus belonging to the Lycoperdacese or similar related forms. 
Pul'sa-ting vac'u-ole — A contractile cavity or cell organ present in some lower 

Pyc-nid'i-um [Gr. puknos] — A perithecum-like body bearing conidiospores, present 

in certain fungi. 
Pyc'ni-um [Gr. puknos] — A parathecium-like body or receptacle bearing pycno- 

Py-re'noid [Gr. purenoeides] — A transparent refractive proteid body found in the 

chromotophores of certain algae. The pyrenoids serve as centers for the 

deposition of starch. 
Pyr'i-form [L. pyrum -(- forma] — Shaped like a pear. 
Qual'i-ta-tive di-vi'sion — Nuclear division in which there is a segregation of 

chromatin material of distnct knd or a segregation of entire chromosomes, 

and not merely daughter parts. 
Quan'ti-ta-tive di-vi'sion — Nuclear division in which daughter chromosomes, de- 
rived from mother chromosomes, are segregated. 
Ra-chil'la [Gr. hrachis] — The axis of a spikelet on which the flowers are arranged. 
Ra'chis [Gr. hrachis] — The axis of a spike, or raceme, on which flowers or spike- 
lets are arranged; also the axis of a compound leaf. 
Ra'di-al section [L. radius] — A section cut longitudinally thru the center of the 

Rad'i-cle [L. radicula, dim. of darix] — The incipient stem and root in an embryonic 

Ra'phe [Gr. hraphe] — A ridge or seam along the side of a seed. 
Raph'i-des [Gr. hraphis] — Minute, usually needle-shaped crystals often occurring 

in bundles in the cells of certain plants. 


Ray flower — One of the marginal or ligulate flowers in the head of a composite. 

Re-cep'ta-cle [L. receptaculttm] — The stem or axis which bears the floral organs ; 
a special branch which bears the reproductive organs in certain algae. 

Re-ces'sive character [L. recessio] — A character possessed by one of the parents 
of a hybrid which may not appear in the hybrid but is nevertheless transmitted 
to the following or a later generation. 

Re-duc'tion division — The division in a sporocyte, oocyte, or spermatocyte in 
which the bivalent chromosomes are segregated into univalents, and in which 
the reduction number appears during the development of the bivalents. 

Re-flexed' [L. reflexus] — Bent backward abruptly. 

Re-pro-duc'tion [L. re -j- producere] — The process by which organisms give rise 
to offspring. 

Res'in duct [L. resina, ductus] — A passage or tube containing resin. 

Res'-pi-ra'-tion [L. respiratio] — The chemical changes taking place in all living 
cells whereby organic constituents are decomposed largely as a result of the 
action of enzymes, liberating energy, water, and carbon dioxide. In ordinary 
respiration, the external manifestations are the taking into the cell of the 
free oxygen of the air and the giving off of carbon dioxide. 

Resting nucleus — A nucleus not in the stage of division. 

Re-tic'u-late [L. reticulatus] — Arranged as a network. 

Re'tro-gres'sive organ [L. retrogressus] — An organ which is passing from a higher 
to a lower or less perfectly developed condition or state of organization. 

Rhi'zoid [Gr. hriza] — A filamentous outgrowth from the thallus or gametophyte,. 
usually functioning as an organ of attachment. 

Rhi'zome [Gr. hrizoma] — An underground stem. 

Root — An absorptive and supporting organ of the sporophyte usually under- 

Root-cap — A special tissue covering the root tip, developed from the calyptrogen. 

Root hairs — Slender thread-like epidermal absorbing cells or filaments develop- 
ing on roots just back of the growing point, from the piliferous layer. 

Ro-sette [L. rosa] — A closely crowded and symmetrically arranged cluster of 
leaves at the end of a branch or stem, usually close to the ground. 

Ru'di-ment — A rudimentary organ. 

Ru'di-men'ta-ry (organ) [L. rudimentum] — An organ or part in the initial, incip- 
ient, or incomplete stage of development; or one that has become reduced 
either in the history of the race or of the individual. 

Rust (plant rust) — Any parasitic fungus blonging to the order Uredinales. 

Sap-ro-phyte [Gr. sapros -\- phuton] — A plant which grows on dead organic 

Sap'wood — The part of the wood, next to the cambium, thru which the water 
mainly passes up the stem; the alburnum. 

Sca-lar'i-form [L. scalaris] — Resembling a ladder; having transverse bars or 
markings like the rounds of a ladder. 

Scale — A highly modified dry leaf as in a winter bud; a flat more or less mem- 
branous outgrowth from a leaf or stem. The leaf-like expansions on th^ 
gametophytes of mosses and liverworts. 

Schi-zog'en-ous (cavity) [Gr. schi'zein -|- genesis] — Produced by the splitting of 
the cell walls as contrasted with lysigenous. 

Scle-ren'chy-ma [Gr. skleros + egchuma] — Any tissue outside of the xylem having 
thickened cell walls, as the fiber cells in the bark. 

Scu-tel'-lum [L. Scutum]— A shield-like outgrowth at the side of the embryo a* 
in the embryo of Zea. 


Sec'ond-a-ry cor'tex [L. secundarius] — The tissue developed on the inner side 
of the cork cambium, the phelloderm. 

Seed — The ripened ovule with the sporophyte embryo and remains of the female 
gametophyte in the anthophytes often with abundant endosperm. The seed 
is not to be compared with a spore. In the anthophytes it contains parts 
of three generations — the parent sporophyte, the parent female gametophyte 
and the embryonic sporophyte together with more or less endosperm. 

.Seed plant — Any plant belonging to the series Spermatophyta. 

.Self-fertilization — The union of a sperm with an egg produced by the same 
hermaphrodite individual. 

Self-pollination — The pollination of a stigma or ovule by male gametophytes pro- 
duced on the same sporophyte as the stigma. 

Self-pru'ning — The process by which living buds and twigs are separated from a 

Sep'al [NL. sepalum] — One of the leaves or divisions of a calyx. 

Sep'tum [L. septum] — A partition or separating wall. 

Se'ta [L. seta] — The stem or stalk of a moss sporophyte. 

Sex'u-al'i-ty [L. sexus] — The quality or state of being distinguished by sex. 

Sex'u-al organs [L. sexus] — The organs which produce the gametes or eggs and 

Sex'u-al re-pro-duc'tion — Reproduction by means of eggs and sperms or by iso- 

Sex'u-al spore — A spore formed by the union of two gametes. 

Sheath (of a filament) (of a leaf) — A thickened outer wall as in some blue-green 
algse; the base of a leaf below the blade investing the stem as in grasses. 

Shoot — A stem with its leaves as distinguished from the root. 

Sieve-plate — The thin perforated wall between the adjacent cells of sieve tubes. 

Sieve-tube — A tube of sieve cells placed end to end in rows and separated by 
sieve plates. 

Si-lic'i-fied [L. silex] — Impregnated with silica. 

Si'pho-no-ste'le [Gr. siphon -j- stele] — A holiow cylindrical stele with or without 

Slime-mold — A plant belonging to the Myxophyta. 

Smut — A plant belonging to the orders Ustilaginales and Tilletiales. 

So-re'di-um [Gr. soros] — A small granula»r body produced on the surface of a 
lichen thallus. 

So'rus [Gr. soros] — A cluster of sporangia in the ferns. 

Spat'u-late [L. spatula] — Widened at the top like a spatula. 

Spe'cies (of plants) [L. species] — A group of more or less similar individuals hav- 
ing a common ancestry and interbreeding readily, with production of fertile 

Sperm [Gr. sperma] — A male gamete; the spermatozoid. 

Spermary [Gr. sperma] — An organ which produces spermatozoids ; the male 
reproductive organ, 

Sper-ma'ti-um [Gr. sperma] — A non-motile spermatozoid, as in red alga, lichens 
and fungi. 

Sper'ma-tog'e-nous [Gr. sperma -f- gignomai] — Sperm-producing. 

Sper'ma-to-zo'id [Gr. sperma -f- zoon -j- eidos] — The male gamete. 

Sper'mo-go'ni-um [Gr. sperma -j- gone] — An organ which produces spermatia. 

Spike — An elongated rigid inflorescence with sessile or nearly sessile flowers. 


Spike'let — A small spike; especially the ultimate flower-custer of the inflorescence 
of grasses and sedges. 

Spin'dle — The spindle-shaped figure of fibers of achromatic substance, formed dur- 
ing karyokinesis, to which the chromosomes are attached. 

Spi'ral wood vess'el — An elongated wood cell containing one or more spiral thick- 
nings of lignin in the wall. 

Spi'r.em [Gr. speirema] — The thread of chromatin formed in the nucleus from 
the chromatin network during nuclear division. 

Spon'gy pa-ren'chy-ma — The layer of loosely arranged parenchyma cells in the 
under side of the leaf. 

Spo-ran'gi-o-phore [Gr. sporos + aggeion -f- pherein] — An organ bearing spor- 

Spo-ran'gi-um [Gr. sporos + aggeion] — A spore-producing organ. 

Spore [Gr. sporos] — A modified reproductive cell. 

.Spore-ling [Gr. sporos -f- A. S. ling] — A young plant or embryo developing from 
a spore on the ground, not in a seed. 

Spore tetrad — The four spores resulting from the two reduction divisions, before 
their separation. 

Spo-rid'i-um [L. Sporidium from Gr. spora] — A small spore produced on the 
promycelium or basidium coming from a teleutospore of one of the Telio- 
sporese; probably a type of basidiospore. 

.Spo'ro-carp [Gr. sporos -f- karpos] — A carpel-like, or enclosed, spore-bearing 

.Spo'ro-cyte [Gr. sporos -j- kutos] — In plants, any cell which undergoes the reduc- 
tion division in producing non-sexual spores. 

Spo'ro-phore [Gr. sporos + pherein] — An organ or structure which bears spores. 

Spo'ro-phyll [Gr. sporos -)- phullon] — A spore-bearing leaf. 

Spo'ro-phyte [Gr. sporos -j- phuton] — The nonsexual generation of plants. 

Sprout (to) — To continue growth, as the sprouting of a bud; to break out of the 
seed and continue growth, as the sprouting of a seed — to be distinguished 
from germination, which see. 

Stalk — The stem or main axis of a plant; the petiole or peduncle, or any similar 

.Stalk cell (of pollengrain) — The cell at the back of the spermatogenous cell and a 
sister cell to it. 

-Sta'men [Gr. stemon, L. stamen] — The organ of a flower which produces micro- 
sporangia, which contain the microspores which later develop into pollen 
grains; the microsporophyll of seed plants. 

Stam'i-nate [L. staminatus] — Containing or producing stamens; having stamens 
only or staminate flowers only. 

Starch — A carbohydrate produced in plants and usually found in the form of 
minute grains in the cells. 

Ste'lar [Gr. stele] — Pertaining to or resembling a stele. 

Ste'le [Gr. stele] — The central cylinder in the stems and roots of vascular plants. 
It develops from the plerome. 

Stem — Any axis which develops buds and shoots, and having definite nodes ; also 
a main axis of a nonvascular plant. 

Ster'e-ome [Gr. stereoma] — The mechanical or strengthening tissue in plants, like 

Ster'ile [L. sterilis] — Xot producing spores, seeds, or gametes. 

Stig'ma [Gr. stigma] — The upper part of a carpel; a special organ of the Autho- 
phyta to catch the pollen grains. 


Stip'u-lar scar [L. stipula] — The mark made on the bark by some deciduous 

Stip'ule [L. stipula] — A bract-like appendage at the base of the petiole of many- 

Stipe [L. stipes] — The stalk of a toadstool or similar structure. 

Sto'lon [L. stolon] — A basal branch rooting at the nodes. 

Sto'ma [Gr. stoma, stomata] — The transpiring pores in the epidermis of the higher 

Stro'bil-us [Gr. strobilos] — A primitive flower or cone, as in a horsetail or pine. 

Style [L. stilus, Gr. stulos] — The narrow elongated part of the carpel or of the 
united carpels, between the ovulary and stigma. 

Sub-merged' [L. submergere] — Growing under water. 

Sub'ter-ra'ne-an [L. sub -j- terra] — Being or growing under the surface of the 

Sug'ar — A sweet, transparent, soluble, crystallizable carbohydrate produced in 
plants thru photosynthesis. 

Sus-pen'sor cells [L. sub -f- pendere] — The row of cells which attach the young 
embryo, at the radicle, to the inner wall of the ovule. 

Sym'bi-ont [Gr. sumbion] — One of the two individuals or species which live to- 
gether in the symbiotic relation or condition. 

Sym-bi-o'sis [Gr. sumbiosis] — The living together of two or more dissimilar 
organisms in more or less intimate association, including mutualism, helotism, 
and parasitism. 

Sym-met'ric-al [Gr. sun -J- metron] — Applied to an organ or part which can be 
divided into equal halves by one or more planes. 

Sym-po'di-al branching [Gr. sun -j- pous, podos] — A system of branching in which 
the main axis is made up of a series of lateral branches because of the 
self-pruning or withering of the terminal bud. 

Syn-ap'sis [Gr. su'napsis] — The fusion of simple chromosomes into multiple ones, 
usually of a bivalent value. 

Synaptic mates. The two corresponding univalent chromosomes which conjugate 
to form bivalents in the prophase of the reduction division. 

Syn-er'gid [ ; Gr. sunergos] — One of the two cells lying above the egg in the 
female gametophyte of Anthophyta. The two synergids and the egg con- 
stitute the egg apparatus. 

Syn'i-ze'sis [Gr. syni'zesis] — The unilateral or central contraction of the chro- 
matin usually seen in the nucleus during the early stages of the reduction 

Tan-gen'tial (section) [L. tangens] — A section cut near the surface of a stem or 
other structure. 

Tan'nin, Tannic acid — An, astringent chemical substance widely diffused thru the 
cells of plants, as in oak bark, oak galls and various leaves and fruits. 

Te-leu'to-spore [Gr. teleute -f sporos] — A resting spore, produced in the Telio- 
sporeae, which gives rise to a promycelium or basidium. 

Te'li-o-spore [Gr. te'los + sporos] — One of the thick-walled chlamydospores or 
winter spores developed in the final stage of the life cycle of a rust fungus. 

Te'li-um [Gr. telos, teleos] — The sorus of the teliostage in the rust fungi. 
Tel'o-phase [Gr. telos -f pbasis] — The last general stage of karyokinesis during 

which the daughter chromosomes are transformed into a resting network. 
Tet-ra-cy'clic [Gr. tessares -j- kuklos] — Having four cycles, as in certain flowers. 


Tet'rad [Gr. tetras] — A collection of four things, as four spores produced from 

one grandmother cell. 
Te-tram'er-ous [Gr. tessares + meros] — Four-parted. 

Tet'ra-spo-ran'gi-um [Gr. tessares -f- sporos -j- ageion] — A sporangium which pro- 
duces tetraspores, as in the red algse. 
Tet'ra-spore [Gr. tessares + sporos] — A nonsexual spore, one of a group of four 

spores resulting from a reduction division as in the red algae. 
Thal'lus [Gr. thallos] — The plant body of a thallophyte, or of the gametophyte of 

the archegoniates. 
Toad-stool — Any fungus in which basidiospores are produced on plates or gills, 

usually umbrella-shaped with a central stalk and terminal cap. 
Tra'che-id [L. trachia, Gr. tracheia] — One of the strongly lignified cells in woody 

tissue in which the end walls are not absorbed. Tracheids commonly have 

bordered pits and are very characteristic of conifer wood. 
Trans-formed organ — One which shows a distinct change in the individual from 

one type of normal structure to another; as a stamen developing into a petal. 
Tran'spi-ra'tion [L. trans -f- spirare] — The process of giving off water vapor thru 

the stomata. 
Trans-verse' sep'tum [L. transversus, septum] — A crosswall or partition. 
Trans-verse' sec'tion — A section cut at right angles to the long axis; a cross 

Trich'o-gyne [Gr. thrix, trichos -j- gune] — The slender, hair-like process at the tip 

of the oogonium, as in red algae. 
Trich'o-phore [Gr. thrix, trichos -f- pherein] — The base of the type of oogonium 

which bears the trichogyne, as in the red algae. It contains the egg. 
Tri-cy'clic [Gr. tri -f- kuklos] — Having three cycles. 
Tri'mer-ous [Gr. tri-f-meros] — Three parted. 
Tri'ple fu'sion [L. triplus, fusio] — The union of the two polar nuclei and a 

sperm to form the definitive nucleus from which the endosperm is developed. 
Tube cell, tube nucleus — The cell in a pollengrain which develops into the pol- 

Tu'ber-ous [L. tuberosus] — Consisting of or bearing tubers, or thickened under- 
ground stems. 
Tu'bu-lar flowers [L. tubulus] — The central disk flowers in a composite as dis- 
tinguished from the ray flowers. ♦ 
U'ni-cel'lu-lar [L. unus -j- cella] — Consisting of but one cell or protoplast. 
U'ni-loc'u-lar [L. unus + loculus] — With one cavity. 
U-ni-sex'u-al [L. unus + sexus] — Having only ovaries or spermaries on one 

individual ; being purely male or female. 
U-niv'a-lent (chromosome) [L. unus -j- valens] — One of the double number of 

chromosomes before their union into bivalents in the reduction division. 
Un'sym-met'ric-al [Un (Gr. an)-|-Gr. sun -(- metron] — Applied to an organ or 

part which cannot be divided into equal halves by one or more planes. 
U're-din'i-um [L. uredo] — The sorus of the second parasitic spore stage in the 

life cycle of various rusts. 
U're-din'i-o-spore [L. uredo -f- spora) — A spore produced in a uredinium. Same 

as uredospore. 
U-re'do-spore [L. uredo -f- spora] — A kind of spore produced by certain rusts. 

They are developed nonsexually and produce a new mycelium directly. 
Vac'u-ole [L. vacuus] — A small cavity in the protoplasm containing water or 

some chemical secretion. 


Valve — One of the two parts of a diatom shell; one of the pieces or segments 
into which a capsule separates at maturity. 

Valve view (of diatom) — The side of the shell which presents the end view of 
one of the valves, contrasted with girdle view. 

Vas'cu-lar bun'dle [L. vasculum] — A bundle of tissue in the higher plants con- 
taining the xylem and phloem, or the wood cells and bast cells. 

Vas'cu-lar plant — Any plant having true vascular tissue in the sporophyte. 

Veg'e-ta-tive prop'a-ga'tion [L. vegetatio, propagatio] — Reproduction by means of 
organs or cells derived directly from the parent individual. 

Vien [L. vena] — One of the branches of the vascular portion of leaves or other 

Ve-na'tion [L. vena] — The arrangement of the veins. 

Ven'ter [L. venter] — The base of an archegonium containing the egg. 

Ven'tral [L. ventralis] — Pertaining to the venter, or to the lower surface in a 
dorsiventral organ. 

Ver-na'tion [L. vernatio] — The arrangement of the leaves in the bud. 

Ve-sic'u-lar [L. vesicula] — Having the form or structure of a vesicle, or bladder- 
like body. 

Ves'sel (xylem) [L. vas] — A long tube in the xylem formed of superposed cells 
which have lost their end walls and are usually marked with dots, pits,, 
rings, or spirals. These vessels are often called tracheae. 

Ves'tige [L. vestigium] — An organ or part which was normally developed in the 
past history of the race, but which has become rudimentary. 

Wood — The xylem; the lignified part of astern. 

Wood fi'ber — A slender cylindrical or prismatic cell in the xylem usually with the 
ends tapering to points. 

Wood pa-ren'chy-ma — A thick-walled paranchyma in the secondary xylem. 

Xe'ni-a [Gr. xenios] — The immediate influence of pollen on the endosperm in 
hybridization caused by the union of the second sperm of the pollengrain 
with the two polar nuclei of the female gametophyte and manifesting itself 
as color, etc. in the grains of corn and various other plants. 

Xe'ro-phyte [Gr. xeros -j- phuton] — A plant growing in dry or desert conditions. 

Xy'lem [Gr. xulon] — The part of the vascular bundle which contains the wood 
cells, as distinguished from the phloem. 

Yeast — A plant belonging to the Saccharomycetales. 

Zo'o-gloe'a [G. zoon -j- gloios] — A mass of bacteria imbedded in a gelatinous 

Zo'o-spo-ran'gi-um [Gr. zoon -)- sporos -j- aggeion] — A sporangium which pro- 
duces zoospores. 

Zo'o-spore [Gr. zoon + sporos] — A motile spore provided with one or more cilia 
or. flagella. 

Zo'o-zyg'o-spore [Gr. zoon -\- zugon -f- sporos] — A zygospore produced by the 
union of two similar zoospores. 

Zyg'o-mor'phic [Gr. zugon -|- morphe] — Applied to a flower or organ which can 
be cut into similar halves by only one plane. 

Zvg'o-spore [Gr. zugon -f~ sporos] — A spore formed by the union of similar or 
nearly similar gametes. 

Zy'gote [Gr. zugotos] — A spore formed by the conjugation of two gametes; any 
sexually formed spore.