296 >, NOTES AND MEMORANDA. 



like, but in no sense to be considered as functionally or pby- 

 siologically a root) rbizo'id system. Tbe author points out, 

 touching the dependent lamifications called "rhizines" in 

 Cladophora fracta, that the spore (here a zoospore) sends 

 down in germinating one or two irregular processes, the 

 rhizines, but with no formation of a septum ; they are not 

 shut off therefore as independent cells. Certain Cladophorege 

 send down from other parts of the plant adventitious rhizines 

 — others offer helicoids on terminal cells. The essential dif- 

 ference then lies in the nature of the rbizo'id organs, formed 

 immediately on germination of the spore, which seems to 

 be correlated with the different nature of the spores, that is, 

 hypnospores in one and zoospores in the other. 



The author points out that, leaving aside vegetative cha- 

 racters and keeping in view only the mode of spore-formation, 

 there is a resem.biance to the motionless spores formed 

 asexually (as indeed are the zoospores) in Vaucheria geminaia 

 (Vauch.), Walz, and V. hamata (Vauch.) Walz. But, as he 

 further points out at some length, the differences are vastly 

 more numerous and important than the resemblances, and 

 Vaucheriaceee, apart from the vegetative characters, may be 

 dismissed as having any very near relationship to the Pitho- 

 phoracese. Nor does there early appear any further group 

 showing any near affinity to this order. 



Reverting however, to the mode of spore-formation the 

 author again refers to Cladophorese, not indeed to the zoo- 

 spore-formation in the latter, but to those propagative cells 

 found in Cladophora, most strongly evinced, by Cladophora 

 fracta. In that form those swollen pear-shaped densely filled 

 joints seem actually to be formed similarly to the mode 

 described for the hypnospores of Pithophora, that is, by the 

 expansion of the upper portion of a joint, the lower retain- 

 ing its original cylindrical figure, and far less densely filled 

 with contents. Now, if a transverse septum were formed 

 just below the widened part, we should have two cells, the 

 upper of which would be perfectly homologous with the 

 spore, as described, of Pithophora, the lower with the sub- 

 sporal cell. If, further, the formation of zoospores were sus- 

 pended, the Cladophora, as the author remarks, would be 

 transformed almost into a perfect Pithophora. The author 

 has seen, in Pithophora cedogo7iia, the true spores, formed in 

 the normal manner, instead of germinating in the usual way 

 and (apparently still m sitii on the plant), develop a branch 

 laterally, quite in the same manner as prolific cells in Clado- 

 phoreae. Therefore the author holds Pithophoracese are to 

 be regarded as " transformed Cladophorese, thus being one ' 



