July 1904] 
Elementory Mycology 
175 
facts lending support to this view are, that some organisms are 
to-day flourishing in media of great extremes of temperature — 
for example in thermal springs and in arctic regions. Again, 
seeds subjected for a time to a temperature of 250° C. below zero 
do not all loose their vitality and they doubtless are more sensa- 
tive to an untoward environment than less complex structures 
would be; but this is approximately the coldness of interplanetary 
space, and would suggest that ultra-imported living matter might 
have been the starting point for mundane organic existence. 
Vegetative Reproduction. — Whatever the facts may prove 
to be in regard to the origin and continuity of living matter, the 
orderly (natural) role of multiplication of individuals at the 
present time is recognized and the processes involved in repro¬ 
duction are, in a measure, understood. Leaves or portions of 
leaves of Begonia are placed in moist sand, whereupon they de¬ 
velop buds and shoots; and thus the florist obtains a new set of 
individual plants. Willow twigs, elder, etc., partially covered 
with moist soil may grow into so-called new individuals. Cut¬ 
tings of very many ornamental or useful plants are used to pro¬ 
vide the desired number of new individuals. Fragments of roots 
or portions of stems may in some cases be similarly used. In other 
cases such structures as runners, stolons, offsets, and bulbs are 
employed. The “artificial” multiplication of useful plants, par¬ 
ticularly the various kinds of fruit trees, is secured by means of 
“budding” and “grafting,” i. e. by the use of buds or twigs taken 
from the particular individuals or kinds which it is desired to 
perpetuate, and inserting on seedling plants, readily grown in 
great quantities, of similar (or closely related) species. In na¬ 
ture we see extensive vegetative multiplication by “sprouts” that 
develop from adventitious buds arising on roots; runners, stolons, 
or bulbs, may develop new plants at varying distances from the 
parent. Another mode of rapid and extended multiplication is 
seen in case of creeping underground stems which are called 
rhizomes; a large number of the Grasses and many other peren¬ 
nial herbaceous plants, including some of the Ferns, are com¬ 
mon illustrative examples. The unicellular plants, as some of the 
Algae, the Bacteria, and many of the Fungi, multiply by a divi¬ 
sion of the cell into two equal parts, each of which is therefore 
a new individual (Fig. 2). The Yeast-plant increases by a 
process that is called “budding.” (Fig. 4.) Here a small por¬ 
tion grows out from the parent cell, gradually enlarges and ex¬ 
hibits the usual elliptical shape; presently it may give rise to 
others and ultimately all may become detached. In some of the fil¬ 
amentous Algae the cells divide repeatedly, and then fragments of 
the parent individual separate and these behave thereafter as 
new and independent plants. Larger or smaller portions of the 
ordinary or specialized vegetative cells in plants of still higher 
groups become detached and these continue an independent exist- 
