RHODOPHYCE., OR FLORIDE” 233 
the cortical layers, and the fruit cavity is of similar 
character to that of the Delessertew. The gonimo- 
blast is a copiously branching tuft of filaments 
of which the terminal cells bear large club-shaped 
carpospores. 
Bonnemaisonia asparagoides is the only British 
form. <Asparagopsis Delilei occurs in the warm North 
Atlantic; and of the other noteworthy genera 
Ptilonia and Delisea occur in southern seas. 
Rhodomelea. 
This is one of the most natural and best defined 
families of Rhodophycee, not only from its repro- 
ductive characters but toa considerable extent its 
vegetative structure as well. The thallus in most 
cases consists of tiers of cells in series, a central 
one with smaller pericentral cells of the same length 
grouped round it. Branching, commonly of a mono- 
podial type, occurs, and the whole shoot is clothed 
more or less with fine hair-leaves if they may be so 
termed. Both antheridia and procarpia are formed 
on these hair-leaves, and are in the great majority of 
cases stalked. The cystocarps are therefore rarely 
sessile. In Polysiphonia, which may be taken as 
fairly typical of the rest of the family, the carpo- 
gonial branch is four or five-celled. The lowest 
of these cells becomes the auxiliary cell and the 
carpogonial branch so bends round that the car- 
pogoninm itself touches the auxiliary cell (Fig. 
77). The other joint-cells adjoiing the one 
which gave origin to the carpogonial branch 
