566 EHODOMELACEAE. 



3. Laurencia intricata Lamour. Essai 43. pi. 3. f. 8, 9. 1813. Not L. intricata 



Kiitz. Tab. Phye. 15: 22. pi. 61. f. a, ~b, c. 1865. 



Laurencia Chauvini Bory, p. p. max. Diet. Class. Hist. Nat. 9: 239. 1826. 

 Laurencia implicata J. Ag. Sp. Alg. 2: 745. 1852. 

 Perhaps only a variety of L. obtusa. 



In shallow water, Rose Island, Great Bahama, Bimini, Abaco, Exuma Chain, Cat 

 Island, Mariguana, and Great Ragged. Island : Bermuda ; Florida ; Cuba ; and Amer- 

 ican Virgin Islands. Type from Antilles. 



4. Laurencia Poitei (Lamour.) M. A. Howe; Collins & Hervey, Proc. Am. Acad. 



53: 118. 1917. 



Fucus Poitei Lamour. Diss. 63. pi. 31. /. 2, 3. 1805. 



Laurencia tuberculosa J. Ag. Sp. Alg. 2: 760. 1852. 



Laurencia mexicana Kiitz. Tab. Phyc. 15: 25. pi. 70. f. c, d. 1865. 



On rocks, etc., in shallow water, New Providence, Berry Islands, Great Bahama, 

 Abaco, Cat Island, Watling's Island, Caicos Islands, and Great Ragged Island : Ber- 

 muda ; North Carolina ; Florida ; the West Indies generally ; Vera Cruz ; and north- 

 ern South America. Type from Santo Domingo. 



5. Laurencia gemmifera Harv. Ner. Bor.-Am. 2: 73. pi. 18B. 1853. 



Laurencia Chauvini Bory, p. p. min. Diet. 'Class. Hist. Nat. 9: 239. 1826. 



Sometimes simulating L. Poitei and L. papillosa, but apparently quite 

 distinct, differing from both in the papillate epidermal cells (at least in apical 

 parts) and differing from L. papillosa, and, in a less degree, from L. Poitei in 

 the larger epidermal cells. 



In shallow water, Berry Islands, Great Bahama, Bimini, Exuma Chain, Cat 

 Island, Watling's Island, Mariguana, and Great Ragged Island : Bermuda ; Florida ; 

 Cuba ; American Virgin Islands. Type from Key West, Florida. 



6. Laurencia papillosa (Forsk.) Grev. Alg. Brit. lii. 1830. 



Fucus papillosus Forsk. Fl. Aegypt.-Arab. 190. 1775. 

 Chondria papillosa Ag. Sp. Alg. 1: 344. 1822. 



On rocks between the tide-lines and in shallow water, New Providence, Berry 

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

 Islands, Great Ragged Island, and Orange Cay : Bermuda ; Florida ; Cuba ; Santo 

 Domingo ; Porto Rico ; American Virgin Islands ; Barbados ; and northern South 

 America ; widely distributed in the warmer seas. Type from the Red Sea. 



7. Laurencia Corallopsis (Mont.) M. A. Howe, in Britton, Fl. Bermuda 519. 



1918. 



Sphaerococcus Corallopsis Mont, in Sagra, Hist. Cuba, Bot. PI. Cell. 49. 



1842; in Sagra, Ic. PL Fl. Cuba, pi. 3. /. 1. 1863. 

 Laurencia cervicornis Harv. Ner. Bor.-Am. 2: 73. pi. 18C. 1853. 



On rocks in shallow water ; reduced abortive forms of what is apparently this 

 species occur also between the tide-lines, New Providence, Berry Islands, Great Ba- 

 hama, and Mariguana : Bermuda ; Florida ; Cuba ; American Virgin Islands ; and 

 Barbados. Type form near Havana, Cuba. 



8. Laurencia nana M. A. Howe, sp. nov. 



Densely cespitose and intricate, rose-red to garnet-brown, mostly 1 to 2 

 cm. high, fragile, often innovating from broken ends, dichotomous or subdichot- 

 omous, the branches more or less concrescent or coherent; main segments 0.15- 

 0.45 mm. in diameter; ultimate branches cylindrie or subeylindrie, mostly 0.1 

 0.35 mm. broad at truncate apex; surface of cortex smooth or lightly crenulate- 

 mammillate, showing numerous or occasional rhizoidal haptera, epidermal cells 

 iiL-hieular-hexagonal and mostly 25-45^, broad in surface view, firm- walled; 

 tctrasporic branches similar to the sterile or slightly enlarged. 



On corals, corallines, and sea-fans, near low-water mark, Mariguana (Howe 5393 

 type), Shroud's Cay (Exuma Chain), and Great Ragged Island. 



