RHODOMELACEAE. 575 



3. Lophosiphonia cristata, Falkenb. Rhodomel. 499. pi 9. f. 7-10. 1901. 



Making a velvety coating on surf-beaten rocks, low-littoral, Berry Islands, Mari- 

 guana, and Great Ragged Island : St. Thomas and Mediterranean Sea. Type from 

 Naples. 



13. DIPTEEOSIPHONIA Schmitz & Falkenb. in Eng. & Prantl, 

 Nat. Pflanzenfam. I 2 : 463. 1897. 



1. Dipterosiphonia dendritica (Ag.) Schmitz, loc. cit. 464. 

 HutcMnsia dendritica Ag. Syst. Alg. 146. 1824. 



Creeping on Chamaedoris and on Laurencia papillosa, Eleuthera : American Vir- 

 gin Islands ; Brazil. Type from Brazil. 



14. AMANSIA Lamour. Nouv. Bull. Sci. Soc, Philom. 1 : 332. 1809. 



1. Amansia multifida Lamour. loc. cit. pi. 6. f. 2C, D, E. 



Usually found washed ashore, Eleuthera : Florida to Brazil. Type from Santo 

 Domingo. 



15. HETEROSIPHONIA Mont. Prod. Phyc. Pol. Antarct. 4. 1842. 



TRICHOTHAMNION Kiitz. Phyc. Gen. 415. 1843. 



Main axes uncorticated, mostly 65-130 u. in diameter; fronds 



1-6 cm. long or high. 1. H. Wurdemanni. 



Main axes strongly corticated, mostly 0.4o-l.l mm. in diam- 

 eter ; the brownish diaphragms of the central siphon visible 

 through cortex ; fronds 4-18 cm. high. 2. H. Gibbesii. 



1. Heterosiphonia Wurdemanni (Bail.) Falkenb. Ehodomel. 638. pi. 16. f. 11. 



1901. 



? Callithamnion crispellum Ag. Sp. Alg. 2: 183. 1828. 



Dasya Wurdemanni Bail.; Harv. Ner. Bor.-Am. 2: 64. pi. 15C. 1853. 



Resembling a species of Dasya, as pointed out on a later page. 



On corallines and various other algae, under shelving rocks, on roots of Rhizo- 

 phora, etc., low-littoral or in shallow water, Berry Islands, Great Bahama, Bimini, 

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

 Inagua : Bermuda and Florida to Barbados ; Adriatic and Mediterranean seas. Type 

 from Key West, Florida. 



2. Heterosiphonia Gibbesii (Harv.) Falkenb. Rhodomel. 653.- 1901. 



Dasya Gibbesii Harv. Ner. Bor.-Am. 2: 59. pi. 15 A. 1853. 



In tide-pools and in shallow water down to 2 meters or more, New Providence, 

 Berry Islands, Great Bahama, Andros, Eleuthera, Cat Island, Exuma Chain, and 

 Watling's Island : Florida. Type from Key West, Florida. 



16. DASYA Ag. Syst. Alg. xxxiv, 211 (as Dasia,). 1824. 

 RHODONEMA Martens, Reise nach Venedig 2: 641. 1824. 



Dichotomous monosiphonous ramelli (2-4 mm. long) springing without order from 



the firm cortex, densely clothing the main axes or deficient in older parts. 

 Stichidia on 1- or 2-celled monsiphonous pedicels, translucent after dehiscence of 



sporangia, showing central axis clearly. 

 Plants mostly 8-80 cm. high, main axes vaguely quasi- 

 pinnate or virgate ; cystocarps pedicellate. 1. D. pedicellata. 

 Plants mostly 3-6.5 cm. high, subdichotomous ; ramelli 

 very soft and mucous, more or less coherent or con- 

 fluent on drying ; cystocarps sessile or subsessile. 2. D. Crouaniana. 

 Stichidia sessile or on 1-celled pedicels, rather opaque after 

 dehiscence of sporangia and conspicuously zonate-annu- 

 late. 3. D. ramosissima. 



