July 1904] 
Elementary Mycology 
181 
science is called — suggests a fruitful field of study in interpret¬ 
ing the apparently chaotic multitude of forms and structures. 
Physiology. — The Point of View may not be primarily in 
relation to structure, but rather to the display of energy in the 
organism — in other words — its Physiology. This branch of 
science is therefore immediately concerned with such problems as 
— how the organism secures materials for food, the manner of 
breaking up chemical compounds into their elements and the re¬ 
combination of these to form organic material, the various changes 
indicated by such terms as digestion, assimilation, respiration, as 
well as the protoplasmic reactions of all kinds displayed by the 
organism and the work it performs. Physiology has primarily 
to do with function rather than structure. But an organism may 
be studied as a whole or as a unit of energy, rather than in refer¬ 
ence to the several phases of more or less intricate action displayed 
within the individual; its reaction to the medium in which it 
lives, its adaptation possibly to a slowly changing, or perhaps a 
more or less unfavorable environment, its behavior when unto¬ 
ward exigencies arise, or when other individuals or other objects 
or any external phenomena directly affect it;— these and other 
related topics are included under the head of Ecology. Ecological 
relations of plants are most intimately connected with their phys¬ 
iology — in fact Ecology might be considered one of the subdi¬ 
visions of Physiology. 
Phytopathology. — Pet another relation should be men¬ 
tioned, namely, that under which the untoward circumstances in¬ 
juriously affect the individual. For example, a parasitic fungus 
may attack a leaf, or fruit, or stem or root, and interfere with its 
normal functions — ultimately, it may be, destroy the part or 
even the whole plant; a soil too rich in plant food or with deficient 
amount of one or more of the necessary food elements, or with 
insoluble compounds, may prove disastrous to the plant; or, again, 
mechanical influences may injuriously interfere with growth or 
cripple the organism; in all such cases pathological, or so-called 
diseased, conditions ensue. A study of the plant with special ref¬ 
erence to such phases has developed a subdivision of Botany to 
which the name of Phytopathology has been appropriately given. 
When it is recalled that there is an enormous number of para¬ 
sitic organisms — Rusts, Smuts, Leaf Mildews, Fruit-rots, 
Blights — that attack the cultivated plants, decreasing sometimes 
annihilating the crops, the practical importance of this branch 
of botany may be realized. The parasitic fungus may be micros¬ 
copic in size and its presence known only by its disastrous effects; 
it may be wholly concealed within the tissue of the host — not 
always breaking through the epidermis even to liberate its spores; 
it may grow on the superficial cells though sending suckers into 
the epidermis of the host-plant for nourishment; it may be very 
simple in structure, even unincellular, or it may display consid- 
