THE ALG 227 
213. Vaucheria: nutrition. Materials for food-making may 
be absorbed from the moist earth or from the water in which 
this plant grows. The abundant chlorophyll suggests con- 
siderable ability to manufacture its own nutrient substances, 
but this plant is not so 
well fitted for securing 
abundant exposure to 
light as is Cladophora. 
It is to be noted that, 
living on the land as 
these plants often do, 
they do not have the 
protection against ex- 
tremes of light and 
temperature 
that water 
alge enjoy. 
214. Vaucheria: re- 
production. As sug- 
gested in section 212, 
vegetative reproduc- 
tion occurs in this 
plant. Asexual repro- 
duction may be started 
by having the end of- 
a branch cut off by a Fic. 177. Vaucheria 
cross wall. The part 1, branch of a vegetative plant; B, branch form- 
that is thus cut off ing zodéspore; z, young zodspore just emerging 
from the sporangium (s); €’, a free zodspore; D, 
proceeds to form a zodspore germinating to form a new plant 
large reproductive body 
(fig. 177, B, C); the wall which surrounds it breaks, and 
after a period of swimming it germinates and forms a new 
plant (fig. 177, D). This special reproductive body is called 
a zodspore (animal spore), or swimming spore. The formation 
of zodspores may be induced in the laboratory by keeping 
Vaucheria plants in a dish of shallow water. 
