CUBAN SEAWEEDS. 203 
been but little studied, a solitary species of a third order, the 
Siphonacez, to which the most striking Cuban Chlorosperms be- 
long. This plant is the Bryopsis plumosa, which grows in rocky 
pools and looks like a small tuft of delicate green feathers. 
The order Siphonaceæ (Fig. 47, structure of a plant of this 
group) contains plants formed of a single large and generally 
branching cell, or of several such cells united into a frond. The 
mode of reproduction, as far as is known, is by zoospores formed 
from the whole contents of the cell and discharged by the rupture 
Fig. 50. 
Fig. 51. 
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Caulerpa ericifolia, 2-3 nat. size. 
Caulerpa Mexicana, nat. size. 
of the cell-wall. In Vaucheria, antheridia* have been seen. The 
largest and most beautiful genus of Siphonacex is Caulerpa. 
This genus has representatives in all tropical seas, some species, 
as Caulerpa clavifera, being cosmopolitan. The single cells of 
which these algæ are composed are very large, being amongst the 
largest vegetable cells known; in C. prolifera, for instance, four 
or five inches long. The cell-wall is thick and membranous, and 
lined with several layers of cellulose. The sac thus formed is 
filled with a semi-fluid endochrome.+ The peculiar character 
which marks the genus is the presence of branching threads which 
*Certain organs answering to the anthers of flowering plants. 
t The coloring matter of the cells. 
