Howe: PHYCOLOGICAL STUDIES 503 
Halimeda simulans sp. nov. 
Dark- or rather light-green when living, sometimes becoming 
yellowish-green on drying, erect or somewhat flaccid, 6-15 cm. 
high, flabellate or subflabellate 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 3-lobed, 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 
subcrateriform, 27-80 p long, 33-40 2 in average maximum diam- 
eter in surface view, truncate or rounded-obtuse, lateral walls in 
contact for } to zp 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 # in maximum width, 
those of the inmost series obovoid, obconical, or clavate, 41-1104 
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: no. 
4332, type (Culebra Island, M.A.H. —also no. 4383); Jamaica: 
"0S. 48376 and 4845 (Montego Bay); Bahama Islands: xo. 3 56L 
(Frozen Cay, Berry Islands). 
Halimeda simulans is a member of the Halimeda tridens (77. 
incrassata) group, being probably most nearly allied to J. 
Agardh’s Hlalimeda incrassata 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 p in 
Maximum diameter, which would throw it into the form cycle of 
fl. 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 
