108 INTRODUCTION TO CEYPTOGAMIC BOTANY. 



purple, or other tints. Reproductive bodies, zoospores, pro- 

 vided with various ciliary appendages, often resembling sper- 

 matozoids ; or inactive cysts, filled with endochrome. Sper- 

 matozoids rarely present. 



2. Rhodospebme^. 



Rose-red, or purple, rarely inclining to brown or green. 

 Fruit— a-, spores contained in particular conceptacles, either 

 external or immersed : b, tetraspores, mostly immersed in the 

 fronds, rarely contained in particular conceptacles, arising from 

 a cell whose endochrome is quadripartite, and which ultimately 

 separates into four distinct bodies. Antheridia often on dis- 

 tinct plants fiUed with active spermatozoids. 



3. Melanosperme^. 



Olive green, incliuing sometimes to brown, monoecious or 

 dioecious. Spores, olive-coloured, either naked or contained 

 in conceptacles, sometimes arising from the division of an 

 endochrome into two, four, or eight. Antheridia often resem- 

 bling the conceptacles, filled with active spermatozoids. Pro- 

 pagation occasionally by zoospores resembling spermatozoids. 



1. CHLOROSPERMB.a;. — Spores green, often resembling sperma- 

 tozoids ; active or inactive. Monoecious. 

 Spermatozoids, rare. 



2. Ehodosperme^. — Spores red. Fruit twofold. Diracious. Sper- 

 matozoids general. 



3. Melanosperme^. — Spores olive. Dioecious or Monoecious. 

 Spermatozoids, general, or represented by 

 similar zoospores. 



89. It will be observed that there are two distinct modes of 

 propagation amongst Algae, the one by zoospores, the other by 

 inactive spores. This circumstance is proposed by Thuret and 

 others as the foundation of a system. It seems, however, that by 

 such an arrangement, plants of close affinities are widely sepa- 

 rated. No one, for instance, can deny that the species included 

 under the old genus Vaucheria are closely allied ; and yet, if this 

 system is adopted, the species must be widely separated from 

 each other. Gaulerpa jjropagated by zoospores will then have 

 nothing to do with Vaucheiia propagated by inactive spores ; 

 while Laminariw will be separated from Fuc4, with which 





