574 RIIODOMELACEAE. 



3. Herposiphonia secunda (Ag.) Ambronn, Bot. Zeit. 38: 197. pi. 4. f. 8, 12. 



1880. 



Hutchinsia secunda Ag. Syst. Alg. 149. 1824. 

 Polysiphonia secunda Zanard. Syn. Alg. Adriat. 64. 1841. 



On Sargassum, Chondria, Lonrenciu, etc., in shallow water, Berry Islands, Great 

 Bahama, Gun Cay. Exuma Chain, Watling's Island, Mariguana, Caicos Islands, and 

 Castle Island : — Bermuda and Florida to Barbados ; Mediterranean and Adriatic seas. 

 Type from the Mediterranean. 



4. Herposiphonia bipinnata M. A. Howe, sp. nov. 



Frond rose-purple, filiculoid or flocculose, free, or subrepent at base only, 

 somewhat bi-tri-pinnate, or paniculate, 2-5 cm. long, the branchlets here and 

 there obviously pectinate-secund; main axes stramineous or decolorate except 

 in youngest parts, 1.50-2.50 /i in diameter, somewhat swollen at the nodes, the 

 segments 11-4-2 times as long as broad, becoming subequal towards apices; peri- 

 central cells usually 10, the central cell large, 50-90 ^u. in diameter; branches 

 obscurely quadrifarious, or subsecund through the abortion of the usually fre- 

 quent lateral long branches, commonly arising from two immediately consecu- 

 tive nodes, one from each, followed by one or two naked nodes, and then by two 

 branches from immediately consecutive nodes, and so on, the branches being 

 sometimes represented by rudiments; long branches abruptly diminishing in 

 size at apex and rather inconspicuously dorsiflexed; short branches 8-12 seg- 

 ments long, slightly flexed or subfalcate, crowned with rather coarse tricho- 

 blasts, often as long as the branch, the segments %-l% as long as broad; 

 sporangia somewhat protuberant, mostly in a single linear series, the sporan- 

 giif erous branch 105-135 ,u in greatest width ; cystocarps ovoid, short-stalked, 

 subtruncate, 380-540 /x X 300-450 /a. 



In technical microscopic characters, the present species seems to be related 

 to H. secunda, from which, however, it is amply distinct, as indicated in the 

 above key. 



On Cymodocea, washed ashore, Whale Cay, Berry Islands (Howe 3^97 — type), 



12. LOPHOSIPHONIA Falkenb. in Eng. & Prantl, Nat. 

 Pflanzenfam. T: 459. 1897. 



Trichoblasts spirally arranged. 



Pericentral cells usually 11-18. 1. L. ohscura. 



Pericentral cells usually 6-10. 2. L. subadunca. 



3. L. cristata. 



Trichoblasts in a single secund series on the convex (dorsal) 

 surface of the strongly hamate tips of the erect branches. 



1. Lophosiphonia obscura Auct. Xot Hutchinsia ohscura Ag. Sp. Alg. 2: 108. 



1828. 



? Conferva intertexta Eoth, Cat. Bot. 1: 188. pi. 3. f. 6. 1797. 

 Folysiphonia reptatunda Suhr; Klitz. Sp. Alg. 806. 1849. 

 PolysipJionia adunca Kiitz. Sp. Alg. 808. 1849. 



Foi'ming mats or a turf on rocks and on roots of Rhizophora between the tide- 

 lines, common. New Providence, Hose Island, Berry Islands, Bimini, Gun Cay, Exuma 

 Chain, Watling's Island. Caicos Islands, and Great Ragged Island : — Bermuda and 

 Florida to the American Virgin Islands ; Adriatic and Mediterranean seas and England. 



2. Lophosiphonia subadunca Kiitz. Phyc. Gen. 418. 1843. 



Hutchinsia ohscura Ag. Sp. Alg. 2: 108 (according to apparent original in 



herb. Ag.). 1828. 

 Polysiphonia harhatula Kiitz. loc. cit. 417. 

 Polysiphonia pygmaea Kiitz. Phyc. Grerm. 313. 1845. 



Making a close nap or turf on surf-beaten rocks, between the tide-lines, Exuma 

 Chain : — southern Europe. Type from Corsica. 



