176 
Journal of Mycology 
[Vol 10 
ence. The parts detached may be very small and simple in struc¬ 
ture or they may be more complex and even highly differentiated. 
Illustrative examples are “soredia” in the Lichens, the “gemmae” 
in Liverworts and Mosses, “hibernacula” in Water Milfoil, 
bulblets in many plants, also viviparous inflorescences. The 
term vegetative reproduction is applied to all of the enumerated 
cases; it is the single cell, or the mass of cells, which is directly 
concerned in the vegetative processes of nutrition and growth 
that — still retaining (at least in large part) the normal func¬ 
tions — gives origin to the new individuals. 
Spore Reproduction.— All or the great majority of cells in 
plants may be said to be nutritive in function; that is, they are 
or have been concerned, directly or indirectly, in the ordinary 
processes of nutrition and growth. But a cell may become physi¬ 
ologically differentiated for quite another purpose; it may loose 
its nutritive function entirely and all of its energies become set to 
the direct or indirect production of a new individual. Such a 
cell, having taken on a reproductive function, is called a spore. 
An example common and easily examined is furnished by the Leaf 
Mildew of the Lilac. The elongated vegative cells (hyphae) 
creep over the surface, sending suckers (called haustoria ) into the 
epidermal cells of the host for nourishment. Presently some of 
the hyphae grow erect and near the end of such an upright coni- 
diophore (as it is termed) constriction of the wall takes place; 
this deepens and finally the terminal portion is wholly abstricted; 
such a reproductive cell, or a sexaul spore, is called a conidium 
FIG. 8. 
FIG. 7 . 
Fig. 7 . Hyphae of a Eeaf Mildew (Ery.), with conidiophores (C.ph.) abstricting 
conidia (Con ). The fungus grows on the surface of the leaf. 
Fig. 8 . Hyphae (C.ph.) of the Celery Eeaf-spot fungus, Cercospora apii (Cer. apii.) ( 
emerging through the stomate of a leaf and bearing Conidia (Con.). 
(Fig. 7). Other conidia are successively abstricted from the same 
conidiophore, which is true not only for this species but also for all 
the Leaf Mildews. In case of some of the Fungi only one conidial 
spore is formed by each conidiophore. In the Grape Mildew 
(Powdery Mildew) the conidiophores emerge from the stomate of 
