RHODOPHYLLIDACEAE. 515 



constricted at the nodes, snbterete in lower parts and strongly flattened above, 

 the ultimate segments mostly J-J of a line wide, lanceolate, oblong, spatulate, 

 obovate, or linear. It is commonly found creeping on the roots of mangroves 

 near the high-water mark, making solid mats or more often intertangled with 

 Caloglossa, Bostrychia and other algae, as at "Walsingham and Hungry Bay. 

 (Phyc. Bor.-Am. 1885.) 



Eucheuma isiforme (Ag.) J. Ag. is a coarse, spiny, much-branched, 

 coralline-red seaweed, forming shrubby tufts from six inches to a foot or more 

 in diameter, with the main axes J-J inch in diameter when fresh. Its more 

 or less whorled ultimate ramnli may be elongate and awl-shaped or short, thick, 

 and merely acute or sometimes blunt. In weathering and fading its color may 

 become scarlet, or yellowish before it reaches its final whitish or translucent 

 condition. The plant has a firm horn-like consistency on drying. It is fre- 

 quently found growing on rocks or washed ashore in shallow bays, as at 

 Hungry Bay, Bailey's Bay, Tobacco Bay, Tucker's Town, etc. (Phyc. Bor.- 

 Am. 1886.) 



Eucheuma Gelidium (J. Ag.) J. Ag. is somewhat similar to the foregoing 

 in size, color, cartilaginous consistency, and spiny habit, but the main axes are 

 decidedly flattened and the branches are pronouncedly two-ranked. It has 

 been found at Harris Bay and on St. David's Island by Hervey. (Phyc. 

 Bor.-Am. 2184.) 



Wurdemannia setacea Harv. forms densely intertangled dark red mats on 

 rocks, on the stalks of Gorgonians, and among the larger algae. The thallus 

 has about the diameter of a horse-hair, is very irregularly branched, and the 

 branches usually cohere and anastomose freely, so that the filaments are not 

 readily separated. Under a hand-lens the rather short ultimate branchlets 

 are mostly acute. On drying, the plant is rather rigid and it does not adhere 

 very well to paper when dried under pressure. It has been found in Hamilton 

 Harbor, at Walsingham, and in Harrington Sound. (Phyc. Bor. Am. 1887 a.) 



Family SPHAEROCOCCACEAE. 



Gracilaria ferox J. Ag. has a copiously branched thallus, with main axes 

 mostly i-i a line broad. These axes are usually distinctly flattened and the 

 branching manifestly disticho-dichotomous, but conditions occur in which the 

 axes are very slightly if at all flattened and in which the branches emerge in 

 nearly all directions. In the latter case the plants bear some resemblance to 

 Hypnea musciformis, but may be distinguished microscopically by the scat- 

 tered instead of localized tetrasporangia. The ultimate branchlets are acute 

 or taper-pointed. The species is rather common in shallow bays. (Phyc. 

 Bor.-Am. 1932.) 



Gracilaria mammillaris (Mont.) M. A. Howe (E-hodymenia mammillaris 

 Mont. Ann. Sci. Nat. II. 18: 252. 1842) has a flat deep red flabellately sub- 

 dichotomous thallus with segments mostly 1-4 lines broad and the ultimate 

 lobes usually rounded-obtuse. It is of occasional occurrence on rocks in 



