EHODOMELACEAE. 523 



and the minute pointed ramuli are rather smaller, more slender, and more 

 aculeate-subulate. The Bermuda specimens that have been referred (Phyc. 

 Bor.-Am. S095) to this species show some of the indicated differences, yet it 

 seems difficult to distinguish them with certainty from W. Blodgettii. 



Murrayella periclados (Ag.) Schmitz, occurs on the roots of mangroves 

 and in rock caverns between the tide-lines, commonly associated with species 

 of Bostrychia. Its main axes are 1 or 3 inches long, free, erect or pendent, 

 from rhizomatous bases, and are plumose with spirally alternating branches of 

 various kinds. The main axes have 4 undivided and uncorticated pericentral 

 siphons throughout, differing in this respect from species of Bostrychia. 

 Some of the branches are simple and monosiphonous, others are branched and 

 monosiphonous, others are short, branched, and polysiphonous at base, and 

 monosiphonous above, and others are long and polysiphonous like the main 

 axes. (Phyc. Bor.-Am. 2096.) 



Bostrychia tenella (Vahl) J. Ag, creeps on the walls of caverns, on 

 shaded rocks, on roots of mangroves, and other objects, mostly near the high- 

 water line or a little above it, often forming a dense, though usually thin, turf 

 in the older parts of the colonies. The main axes are mostly ^-1 inch long and 

 are twice or thrice pinnately branched, the somewhat palmate-pinnate ultimate 

 branchlets ending in monosiphonous prolongations that are usually 10-40 cells 

 long. The main axes and principal branches of this and of the other Bermu- 

 dian species of Bostrychia are densely corticated. The tetraspores occur in 

 cylindric-rostrate or lanceolate swellings (stichidia) of the primary or sec- 

 ondary corticated branches, these stichidia being 4-10 times as long as broad 

 and moderately decurved. (Alg. Exs. Am. Bor. 137, as B. calamistrata ; Phyc. 

 Bor.-Am. 1894a, h, c — all more or less mixed with other species of Bostrychia 

 in the set examined.) 



Bostrychia Sertularia Mont, is found chiefly on the roofs of caverns above 

 the ordinary high-water line. It is closely related to B. tenella, with which it 

 is sometimes associated, but is apparently distinct. It is more slender and 

 delicate in all its parts, the main axes are regularly and pectinately bipinnate, 

 the ultimate branchlets are mostly 6-15 cells long, sometimes monosiphonous 

 except at base, sometimes irregularly polysiphonous except for one or two cells 

 at apex; in the monosiphonous parts, the cells are mostly broader than long, 

 while in B. tenella, the reverse is true; when, as occasionally happens, the 

 monosiphonous apices are more prolonged, the prolongations are commonly 

 decolorate, which is rarely the case in B. tenella. The stichidia are ovoid or 

 short-cylindric-clavate, mostly 2-4 times as long as broad, and are acute, 

 obtuse, or apiculate. The color of the plant is a blue- or violet-purple, while 

 that of B. tenella, even when growing with it, is a more brownish purple. 

 (Alg. Exs. Am. Bor. 138; Phyc. Bor.-Am. 2094.) Bostrychia Macci Crouan, 

 at least as represented by Maze & Schrannu, Alg. Guad. S'JO in herb. Mus. 

 Paris, is this species. 



Bostrychia Montagnei Ilarv. is a much larger plant than either of the 

 two preceding species, being 1^-4 inches long, and, with its tri-quadripinnatc 



