610 DERB'ESIACEAE. 



Cay, Mariguana, Caicos Islands, and Great Ragged Island : — Bermuda and Florida 

 to South America ; Indian and Pacific Oceans. Type from St. Croix, American 

 Virgin Islands. 



Variable in the number of ranks of the ramuli and in the length of the ramuli. 

 The forms or varieties chiefly represented are the typical form, the var. ericifolia 

 (Turn.) Web.-v. Bosse, and the var. Lycopodiuui (J, Ag.) Web. -v. Bosse. 



10. Caulerpa racemosa (Forsk.) J. Ag. Till Alg. Sjst. 1: 35. 1873. 



Fucus racemosus Forsk. Fl. Aegypt.-Arab. 191. 1775. 



Fiicus uvifer Turn. Hist. Fuc. 4: 81. pi. 230. 1819. Xot Fucus uvifer 



Forsk. Fl. Aegypt.-Arab. 192. 1775. 



Caulerpa clavifera uvifera Ag. Sp. Alg. 1: 438. 1822, 



On reefs in shallow water and in more sheltered places, as on roots of RMzo- 

 phora. New Providence, Rose Island, Bimini, Exuma Chain, Watling's Island, At- 

 wood Cay. and Castle Island : — Bermuda and Florida to Barbados : widely distributed 

 in tropical and subtropical seas. Type probably from the Red Sea. 



11. Caulerpa clavifera (Turn.) Ag. Sp. Alg. 1: 438. 1822. 



Fucus clavifer Turn. Hist. Fuc. 1: 126. pi. 57. 1808. 



Caulerpa racemosa clavifera Web.-v. Bosse, Ann. Jarcl. Bot. Buitenzorg 



15: 360. pi. 33. f. 1-5. 1898. 

 Caulerpa racemosa uvifera Web.-v. Bosse, loc. cit. 362 p.p. 



Habitat same as C. racemosa. Exuma Chain, South Cat Cay, Mariguana, 

 Caicos Islands, and Great Ragged Island : — Florida to Barbados ; widely dis- 

 tributed in tropical and subtropical seas. Type from the Red Sea. 



Caulerpa racemosa and C. clavifera sometimes approach each other in form 

 and habit and rarely occurring specimens are difficult to determine, but the writer 

 has often seen the two growing close together, in apparently identical surroundings 

 (especially in Porto Rico and Jamaica) and maintaining their distinctions so per- 

 fectly and strikingly that it seems more satisfactory to treat them as independent 

 species than to follow the prevailing modern fashion of regarding them as forms 

 of a single polymorphous species. 



Family 11. DERBESIACEAE. 



1. DERBESIA Solier, Ann. Sci. Xat. Bot. III. 7: 158. 1847. 

 1. Derbesia vaucheriaeformis (Harv.) J. Ag. Till Alg. Syst. 5: 34. 1887. 



Chlorodesmis C^) vaucheriaeformis Harv. Ner. Bor.-Am. 3: 30. pi. 40 D. 



1858. 

 Derhesia tenuissima Farl. Mar. Alg. N. E. 60 p.p. pi. 4. f. 4. 1881. Not 



B. tenuissima (De Not.) Crouan. 



On rocks in a salt spring, high littoral. Cave Cays. Exuma Chain : — southern 

 Massachusetts, Bermuda, and Florida. Type from Key West, Florida. 



The only Bahamian collection seems to be sterile, like Harvey's original ; its 

 filaments are somewhat coarser, being 35-93 p, in diameter, while those of the type 

 are 30-52 /i ; the plants are also much darker green than Harvey's specimens at the 

 present day. but the latter have doubtless suffered some loss of color in nearly 

 seventy years of preservation. 



2. BRYOBESIA Web.-v. Bosse, Ann. Jard. Bot. Buitenzorg 24: 26. 1910. 

 1. Bryobesia cylindrocarpa sp. nov. 



Filaments sparingly subdichotomous, 5-15 mm. long, 75-156 /z in diameter, 

 very rarely septate, their walls mostly 3-10 /x thick, the branches occasionally 

 with a septum at the base ; sporangia short-cylindric, obovoid, or eylindric-elavate, 

 150-450 fl X 90-180 fx, sessile, erect or erecto-patent, constituting one arm of a 



