288 
THALLOPHYTES. 
the cortical layer (r) of the carpogonium commences ; out of the cells that support it 
proceed branches {A, og") which cling closely to it. These again form branches which 
also cling closely and divide transversely; the branchlets of other branches also ramify 
{B) ; and only the neck of the carpogonium does not become covered with the cortical 
layer. All this happens between May and July; later, the contents of the remaining cells 
of the plant disappear, and the walls of the cortical layer of the carpogonium assume 
a deep dark-brown colour. The further development of the oospore within the carpo- 
gonium now covered with its cortical layer begins only in the next spring; a paren- 
chymatous tissue is formed by successive bipartitions ; the cortical layer splits and is 
Fig. 187.—^ part of fertile thallus of Coleochate pul-vmata {X350); 5 ripe carpogonium enclosed in its cortical layer; 
C germinating sporocarp, in the cells of which the zoospores are formed ; D zoospores (B—D x 280, after Pringsheim). 
thrown off (Fig. 187, C) ; and from each cell arises a zoospore, and from this again an 
asexual plant. C. scutata (the most abnormal species) deviates from these processes 
only so far that in it the carpogonia provided with their cortical layer lie on the surface 
of the disc, and the antheridia are the result of divisions of disc-cells into fours. 
Pringsheim [loc. cit.) has already pointed out various relationships existing between 
the Goleochaeteae, the Florideae, and the Gharaceae. 
B. The Floride^. 
The carpogonium is either unicellular or composed of several cells, and it is provided 
with a permanently-closed trichogyne. If the carpogonium is multicellular, the tri- 
chogyne is borne by a lateral row of cells, which is termed the trichophore. Fertilisation 
is effected by non-motile rounded antherozoids which become attached to the trichogyne. 
As a consequence of fertilisation the basal portion of the carpogonium, which does not 
form the trichophore, forms a great number of spores by budding, each spore being the 
terminal cell of a short branch. The mass of spores is usually surrounded by an invest- 
ment and thus a cystocarp is formed. 
The Florideae^ are a group of Algae of extraordinarily variable form, belonging, 
^ Nägeli und Cramer, Pflanzenphys. Unters. Zürich, Heft I. 1855; Heft IV. 1857.— Thuret, 
Ann. des Sei. Nat. 1855, Recherches sur la fecondation, &c. — Pringsheim, Ueber die Befruchtg. u. 
Keimung der Algen, Berlin 1855. — [Quart. Journ. Micr. Sc. 1856, vol. IV, pp. 63, 124.] — Nägeli, 
