Howe : Phycological studies 569 



Cladocephalus gen. nov. 



A genus of Chlorophyccae of the family Codiaccae. Thallus 

 erect, consisting of capituluni 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 Pcnicillits in habit and form, is most nearly allied 



to Avrainvillea^ being in some respects intermediate between that 



genus and Udotca, It differs from both Avrainvillca and Udotea 



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



lum ; from Avrahivillea 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. Cladocephahts is doubtless as distinct from 



Avrainvillea as Avrainvillca is from Udotea and more so than 



Rhipocephalvs is from PcnicilhisJ^ The genus, so far as known to 



the writer, is monotypic, the only species being 



Cladocephalus scoparius sp. nov. 



Very 



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, i-'j 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, varymg 

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

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

 subcylindrical or complanate, O.3-2 mm. broad, frequently connate 

 at points of casual contact, now and then subdenticulate near 



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

 & Mag. Nat. Hist. IV. lO : 139-141. /^. 9- 1S72). is very different in structure, if 

 indeed it is really a plant. 



