576 EHODOMELACEAE. 



Dichotomous monosiphonous ramelli subverticillate find often 

 subsquarrose, sometimes lightly corticated at base ; main 

 axes well corticated. 4. D. in oil is. 



Monosiphonous ramelli spirally disposed, patent, divaricate, or 



subsquarrose, divaricately dichotomous. 



Main axes 0.250.75 mm. in diameter, corticated except in 

 youngest parts ; cystocarp subspheric-rostrate, 0.67-0.92 



mm. broad. 5. D. CoUinsiana. 



Main axes 0.1-0.3 mm. in diameter, uncorticated or slightly 

 corticated near base ; cystocarp conic-ovoid, about 0.2 

 mm. broad (immature). C. D.rigidula. 



1. Dasya pedicellata (Ag.) Ag. Syst. Alg. 211. 1824. 



Spliaerococcus pediceUatus Ag. Sp. Alg. 1: 321. 1822. 



Rliodonema elegans Martens, Eeise naeh Veuedig 2: 641. pi. 8. 1824. 



Dasya elegans Ag. Sp. Alg. 2: 117. 1828. 



Mostly in shallow water, New Providence, Berry Islands, and Great Bahama : 

 Massachusetts to Bermuda ; Florida ; and the northern West Indies ; Adriatic and 

 Mediterranean seas ; Canary Islands. Type from New York. 



The southern specimens are sometimes yellowish when living instead of the cus- 

 tomary lake-red. 



2. Dasya Crouaniana J. Ag. Till Alg. Syst. 6: 95. 1890. 



On surf-beaten rocks at low-water mark, Exurna Chain : Florida and Guade- 

 loupe. Type from Guadeloupe. 



3. Dasya ramosissima Harv. Ner. Bor.-Am. 2: 61. 1853. 



The verticils of sterile cells of the stichidia are inclined to be protuberant 

 and they occasionally develop into few-celled simple or one-branched, tricho- 

 phylls. In two observed cases the stichidium was forked near the apex. 



On roots of Rhisophora near low-water mark, Great Bahama : Florida. Type 

 from Key West, Florida. 



4. Dasya mollis Harv. Ner. Bor.-Am. 2: 62. 1853. 



On roots of Fhisophora. under shelving rocks, etc., near low-water mark, Exuma 

 Chain and Little Inagua : Florida and Cuba. Type from Key West, Florida. 



5. Dasya CoUinsiana M. A. Howe, in Britton, Fl. Bermuda 524. 1918. 



The only specimen seen differs from the Bernnulian type in being more 

 laxly branched, in being less manifestly dichotomo-corymbose, in the more 

 ' ' ocellate ' ' congestion of the ramuli at the apices, and in the lighter cortica- 

 tion. It also bears cystocarps, hitherto undescribed for this species. These are 

 sessile, subspheric-rostrate, 670-920 /a broad, 600-750 fj. high (without beak) 

 the beak being 350-500 /u, long. In its cystocarps it seems to resemble D. 

 ramosissima, but the ramuli of D. CoUinsiana are coarser and more divaricately 

 dichotomous and have a regularly spiral arrangement while those of D. ramosis- 

 sima are irregular or inclined to be subverticillate. 



In 2 meters of water, Great Bahama : Bermuda. Type from Bermuda. 



6. Dasya rigidula (Kiitz.) Ardiss. Florid. Ital. 2: 140. 1878. 



Eupofjonium rigidulum Kiitz. Phyc. Geu. 415. 1843; Tab. Phye. 14: pi. 85. 



/. c, d. 1864. 

 Eupoyonium squarrosum Kiitz. Phvc. Geu. 415. 1843; Tab. Phyc. 14: pi. 



85. /. a, &. 1864. 

 Dasya squarrosa Zanard. Mem. 1st. Veneto 13: 163. pi. 53B. 1866. Not 



Dasya squarrosa Harv. in Hooker, J. D., Fl. New Zealand 2: 232. 1855. 



Much resembling Heterosiphonia Wurdcmanni in size, habit, and micro- 

 scopic characters and easily confused with that species, but differing in its 

 radial instead of dorsiventral organization, in having its ramuli spirally dis- 



