59 

 Cladocephalus Howe 



in Buil. Torrey Bot. Club. XXXII. 1905. p. 569. 



Cladocephalus Börgesen in Vid. Medd. nat. Foren. Kjóbenh. 1908. p. 44. 

 Cladocephalus Collins Green Alg. N. Amer. in Tufts College Studies II. 1909. p. 396. 

 Cladocephalus Wille in Engler und Prantl natürl. Pflanzenfam. I. Teil, 2. Abteil., Nachtrage 

 1910, p. 128, fig. 66. 



Plant uncalcified, green or brown, of varied habit, erect, either scopulaeform, or fla- 

 belliform, or excentrically subinfundibuliform. Stipes simple or branched, long or short, stout 

 or slender, corticated, attached at base by a mass of rhizoids ; medullary filaments and cortex 

 subsimilar to those of frond. 



Frond either deeply divided into an irregular, subcompressed, brushlike capitulum, or 

 undivided, flabelliform, or excentrically subinfundibuliform and zonate. 



Main filaments of frond radiating from stipes to periphery, subparallel, dividing dicho- 

 tomously without constrictions, one branch of each pair carrying on the axis of the main 

 filament, while the other becomes pseudo-lateral, thinner and tapering, and repeatedly and 

 divaricato-dichotomously subdividing, forms its portion of the densely interwoven labyrinthine 

 cortical covering of the frond. 



Key to the Species. 



Plant scopulaeform or besom-shaped. Medullary filaments 30 — 75 jx in diam. 1. C. scoparius. 



Plant flabelliform. Medullary filaments 30 — 75 u. in diam 2. C. luteo-fuscus. 



Plant excentrically infundibuliform. Medullary filaments 15 — 25 p. in diameter. 3. C. excentricus. 



1. Cladocephalus scoparius M. A. Howe 



in Buil. Torrey Bot. Club XXXII 1905. p. 569, pi. 25 and pi. 26, figs. 11 — 20. 

 Cladocephalus scoparius Collins Green Alg. N. Amer. in Tufts College Studies II. 1909. p. 396. 

 Cladocephalus scoparius Wille in Engler und Prantl, op. cit. p. 129. 



Hab. Atlantic. West Indies, Bahama Islands, Great Exuma, Georgetown, in a tidal pond, on 

 sandy or muddy bottom in 2 — 10 dm. of water (low tide), Howe, n° 4079! also New 

 Providence, south shore, Howe n° 3081. 



"Very dark green or nigrescent when living, commonly becoming yellowish-brown, 

 * substramineous or olivaceous on drying, solitary or gregarious, 5 — 14 cm. high; rhizoids 

 "forming a somewhat bulbous mass; stipes 2 — 10 cm. high, 3 — 7 mm. thick, subcylindrical 

 "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 apices : filaments more 

 "or less fuscous in the older parts, sometimes bright-green in the younger; filaments of the 

 "cortex labyrinthine, lightly torulose when young, the ultimate branches in older parts 6 — ii u. 

 ""in diameter, finally subhyaline ; filaments of medulla cylindrical or lightly and irregularly 



