agp aie ieel ae ae 
THE THALLOPHYTES 359 
enters it and passes to the ovum in the basal cell where fertiliza- 
tion is effected. The zygote forms filaments called gonimoblasts 
which give rise to carpospores or fruits called cystocarps which con- 
tain carpospores. 
Chondrus crispus and Gigartina mamillosa (Fam. Gigartinacee) 
when dried and bleached, constitute the official drug CHoNDRUS, 
& ™ 
a \ SAT " 
cna TE at 
Se NR 
Fic. 263.—Fucus vesiculosus. Transverse section through the outer region of a 
portion of the receptacle of a female plant showing an odgonial conceptacle and 
adjacent tissues. 50. 0, odgonium within a conceptacle; p, paraphyses; ¢f, 
epidermis; co, cortex; ps, pseudoparenchyma of irregular cells having mucilaginous. 
walls. 
Irish Moss or Carragheen. Both are purplish-red in color. 
Each consists of a dichotomously branched thallus the lower 
portion of which is differentiated as a stipe or stalk; the basal 
portion of which, called the holdfast, clings to the rock. ‘The 
upper part is several times forked and its terminal segments 
appear notched or bilobed. Scattered here and there over the 
segments of the thallus will be noted sporangia which, when 
mature, contain tetraspores. In Chondrus crispus the sporangia are 
