2 3 



EHODOSPERMS. 



PART II. 



every instance, the perfect spore is a dense grumous 

 mass surrounded by a hyaline sub-gelatinous coat con- 

 sisting of at least two membranes. The situation, mode 

 of growth, and structure of the nuclei vary almost 

 infinitely, and together with the structure of the 

 frond afford the distinctive marks by which the genera 

 are separated from each other. 



The spores and tetraspores are equally capable, like 

 buds, of reproducing their species ; but the spores are 

 believed to be in some cases fertilized by spindle- 

 shaped particles, and 

 consequently are con- 

 sidered to be the true 

 fruit. Antheridia, or 

 sacs containing these 

 particles, have been 

 discovered in va- 

 rious genera of Eho- 

 dosperms. Although, 

 as a rule, the red 

 Algse have two 

 modes of vegetative re- 

 production, yet there 

 CL BM are various species 



Pig. 24. Vertical sections of conceptacles : a, Graci- ln WniCn 

 laria armata ; b, Grinnelia americana ; c, Corallina ^^1-^ VIQ-T 

 officinalis, the membrane of which, more highly Ulil j Uct ' v 

 magnified, is shown at d. been met with. 



A large proportion of the higher Ehodosperms is dis- 

 tinguished from those possessing the preceding mode 

 of fructification by the internal structure of their 

 reproductive nuclei. In some of these Algse the nuclei 

 are divided into two equal chambers by a fibro-cellular 

 substance to which the spores are attached ; in others, 

 pear-shaped spores radiate from a fibro-cellular sub- 

 stance at the base of the nucleus. There are, moreover, 

 Algse which have nuclei containing conical spores whose 



