Howe : Phycological studies 569 



Cladocephalus gen. nov. 



A genus of Chlorophyceae of the family Codiaccae. Thallus 

 erect, consisting of capitulum and stipe, the latter attached to the 

 substratum by matted rhizoids, all parts destitute of calcareous in- 

 crustation. Stipe and branches of the capitulum corticated, the 

 medullary portion consisting of parallel, sparingly dichotomous 

 chlorophyllose filaments, the cortical layer composed of much 

 narrower, intricate, repeatedly divaricate-dichotomous filaments, 

 which are finally deficient in chlorophyl. Capitulum thamnioid 

 or scopiform, made up of numerous, irregularly dichotomous, 

 non-zonate, often coherent or anastomosing branches. Mode of 

 reproduction unknown. 



The genus Cladocephalus, though having a slight superficial 

 resemblance to Penicillus in habit and form, is most nearly allied 

 to Avrainvillea, being in some respects intermediate between that 

 genus and Udotea. It differs from both Avrainvillea and Udotea 

 in having a thamnioid or scopiform capitulum instead of a flabel- 

 lum ; from Avrainvillea also in possessing a well-differentiated 

 cortex ; from Udotea also in the absence of zonation and from its 

 corticated species in the intricate, labyrinthiform character of the 

 cortex, which is made up of more regularly dichotomous, less 

 pectinate filaments. Cladocephalns is doubtless as distinct from 

 Avrainvillea as Avrainvillea is from Udotea and more so than 

 Rhipocephalus is from Penicillus* The genus, so far as known to 

 the writer, is monotypic, the only species being 



Cladocephalus scoparius sp. nov. 



Very dark green or nigrescent when living, commonly becom- 

 ing yellowish-brown, substramineous, or olivaceous on drying, 

 solitary or gregarious, 5-14 cm. high; rhizoids forming a some- 

 what bulbous mass: stipe 2-10 cm. high, 3-7 mm. thick, sub- 

 cylindrical or somewhat complanate, often alate or canaliculate 

 above, simple or occasionally once or twice dichotomous, the 

 branches sometimes again connate : capitulum scopiform, varying 

 in outline from elongate-fusiform or elongate-ellipsoid to obovoid 

 or subspherical. often somewhat flattened, 3-8 cm. long ; branches 

 subcylindrical or complanate, 0.3-2 mm. broad, frequently connate 

 at points of casual contact, now and then subdenticulate near 



* Codiophyllum J. E. Gray, judging from the author's description and figures (Ann. 

 & Mag. Nat. Hist. IV. 10 : 139-141. pi. g. 1872), is very different in structure, if 

 indeed it is really a plant. 



