Howe: Puvcological studies 503 



Halimeda simulans sp. nov. 



Dark- or rather lii^ht-i^recii when hviii^^, .sometimes becoming 

 yellowish-f^reen on dryin*^, erect or somewhat flaccid, 6-15 cm. 

 hi<^h, flabellate or subflabeUate in habit, sessile or subsessile, the 

 one or two lowest, more or less modified, flattened segments often 

 forming a sort of stipe, strongly calcified, the calcification soon in- 

 volving the medulla and reaching the outer surface of the peripheral 

 utricles, the surface dull or slightly nitent, appearing smooth, solid, 

 and compact, even under a lens ; branching in one plane, usually 

 trichotomous : rhizoids commonly forming a bulbous mass with 

 the adherent sand: segments discoid, plane or obscurely i- or 

 3-nerved, subquadrate-reniform, subquadrate, or rhombic-ellip- 

 soidal, rarely obovate, nearly always broader than long, mostly 

 subentire or 3-7-crenulate, sometimes 3-dentate or 3lobed, 2-9 

 mm. long, 4-12 mm. broad, 0.5-2 mm. thick (those of extreme 

 base now and then 3 mm. thick) : peripheral utricles turbinate or 

 s u be rate ri form, 27-80/^ ^ong, 33-40// in average maximum diam- 

 eter in surface view, truncate or rounded-obtuse, lateral walls in 

 contact for \ to -^^^ their length, usually cohering rather firmly on 

 decalcification : utricles of the subcortical layer in a double, triple, 

 or rarely quadruple series, those of the outmost series turbinate, 

 obovoid, subglobose or ellipsoidal, 30-72 /i in maximum width, 

 those of the inmost series obovoid, obconical, or clavate, 41-1 lO/i 

 in greatest width : filaments of the central strand strongly coherent 

 at the nodes, communicating there with those adjacent by open 

 pits or very short tubular processes and exhibiting there thickened 

 and often colored walls : sporangia unknown. [Plate 29.] 



Growing on a sandy bottom or occasionally on stones in 3 dm. 

 of water and down to a depth of several meters. Porto Rico : ?!o. 

 4JJ2, type (Culebra Island, M.A.H. — also uo. 4383); Jamaica: 

 nos. 4837b and 4843 (Montego Bay) ; Bahama Islands : no. 3361 

 (Frozen Cay, Berry Islands). ^ 



Halimeda simulans is a member of the Halimeda tridens (//. 

 incrassatd) group, being probably most nearly allied to J. 

 Agardh's Halimeda iticrassata a ovata [Till Alg. Syst. 5 : 86. 

 1887. — "Hab. ad insul. Noukahiva (Jardin) " ] the evident type 

 of which is no. 15892 in the Agardh herbarium at Lund. But 

 the peripheral utricles of this Noukahiva specimen average 50 /i in 

 maximum diameter, which would throw it into the form cycle of 

 H. tridens according to the measurements which thus far have 

 proved reliable in helping to distinguish the West Indian species 

 of this group. The Noukahiva plant is also less calcified than our 



