94 
Journal of Mycology 
[Vol. 19 
ganisms or decaying matter the fungi may inhabit only the sur¬ 
face of the host or matrix; the absorption may be direct or 
suckers, usually very simple, may be developed that penetrate 
to some depth. They may however reside only in the interior 
of the host, or deep-seated in the nourishing substance. An 
example of the former is seen in the common Leaf Mildew a 
whitish or later dingy coating on leaves of the Lilac or of the 
Cherry; of the latter may be mentioned the bacteria that cause 
splenic fever or tuberculosis. Some fungi may live on the sur¬ 
face in part and concealed in tissue in part. The oxygen neces¬ 
sary for the activity of these organisms may be taken from the 
atmosphere or in case of some of the simpler fungi it is ab¬ 
stracted from the tissues or the mass of organic matter they 
occupy — necessarily disintegrating or decomposing the latter. 
Structure of Fungi. — Special structures or organs of 
plants and other organisms have doubtless arisen in response to 
their needs; it is plain at any rate that the organs are in general 
adapted to the functions to be performed. The slender tubular 
root-hairs of the land plants are well fitted to absorb moisture 
from soil particles and the leaves by their expanded form and 
peculiar structure take carbon dioxide from the air, exhale mois¬ 
ture and collect the oxygen necessarily consumed in the libera¬ 
tion of energy requisite for the performance of various processes. 
Such forms and mechanical structures as trunk, stem, branches, 
and twigs, or leaf stems, are developed for the support of the 
leaves which must be hung out to the sun and bathed in the air. 
So important physiologically is this display of foliage that the 
modern botanists describe the leaf as a ‘light-related organ 7 and 
refer its peculiar structure to the character of the work to be per¬ 
formed. The floral leaves — using this word to include all the 
organs of the flower—have very different and peculiar functions 
to perform, and they in turn are of such form and structure as 
suits the work to be done. Now, the Fungi gain their livelihood 
without chlorophyll — hence possess no leaves ; having no leaves 
to support and display, they have need of no twigs, branches or 
stems. Resting on other plant bodies or growing within tissues 
their cell walls need not be lignified, need not be thickened nor 
of large dimensions. As a matter of fact the plants of this group 
are often extremely simple as well as very minute. Even when 
they are large, as for example a Mushroom, the cells of which 
they are composed are very simple and homogenous as com¬ 
pared with what is found in the varied and complex tissues of a 
vine or a tree. 
Algae. — When contrasted with Algae (pronounced al'-je 
— the g having the sound of j in the word jeer), which are 
closely related in structure to the Fungi, the conspicuous dif¬ 
ference is in the presence of chlorophyll in the former and its 
