96 L. HILLIS-COLINVAUX 



The firmness of the connections between the nodal medullary filaments 

 also varies, the constituent filaments at times communicating mainly 

 by a restricted number of narrow tubular processes which may be 

 relatively easily severed, rather than by numerous well-developed broad 

 short tubes. In addition, the general appearance of the basal portion 

 of the plant may differ. Specimens from the Caribbean often appear 

 distinctly caulescent, and in older plants from this region the lower 

 branches may consolidate laterally to form a fan-shaped, erect basal 

 portion. The stipe region in many Pacific specimens generally is 

 restricted to one or two subcylindrical to subcuneate segments, the 

 upper one supporting several branches. 



Halimeda favulosa Howe 



Figure 23. 



Halimeda favulosa Howe (1905b), p. 563, Plate 23, Pig. 2; Plate 24; Plate 26, 

 Figs 1-6; Collins (1909-1918), p. 401; Hillis (1959), p. 370, Plates 4-6, 

 8, 12. 



Plants attenuate, suberect or somewhat flaccid, to 22 cm tall excluding 

 the holdfast, which is moderately well developed; calcification moderate; 

 surface dull, rugose and appearing pitted; branching sparse, mainly 

 ditrichotomous ; basal segments commonly compressed- cylindrical to 

 trapezoidal, often forming a short stipe and supporting several segments 

 which remain separate or consolidate laterally, either entirely or in part, to 

 form a fan-shaped unit; other segments friable, cylindrical to subcuneate, 

 the upper margin two to five lobed, the resultant arms compressed or terete, 

 to 9 mm long, 13 mm broad and averaging 1-0-1 -5 mm in thickness. 



Cortex of two to three layers of utricles; outermost utricles (110-)125- 

 220(-260) fxm in surface diameter, 170-280(-400) [xm long in section, 

 separating or remaining slightly attached after decalcification, appearing 

 rounded in surface view, in section sometimes constricted basally forming a 

 conspicuous bulb; one, two or four supported by each secondary utricle; 

 secondary utricles 100-150(-190) ^m broad, 170-275(-424) (j,m long. 



Nodal medullary filaments uniting as a single group for a distance of 

 approximately 28-50 [j,m, adjacent filaments communicating by pores; 

 walls in this region thickened and pigmented. 



Type specimen. Bahamas, Cave Cays, Exuma Chain, Howe 3981, 

 19 February, 1905 (NY). 



Habitat. Grows in sand, mud, or other unconsolidated substrate. 



Geographic distribution. North-western Atlantic; uncommon to 

 rare. 



