588 CORALLIXACEAE. 



2. Fosliella Lejolisii (Rosan.) M. A. Howe, comb. nov. 



Melobesia /.< jolisii Rosan. Mem. Soc. Imp. Sci. Xat. Cherbourg 12: 62. 

 pi. 1. f. 1-13. 1866. 



On Thalas8ia in shallow water, Berry Islands and Watling's Island : Nova Scotia 

 to Florida ; Europe. Type from Cherbourg, France. 



3. Fosliella Chamaedoris (Fosl. & Howe) M. A. Howe, comb. nov. 



Lithophyllum Chamaedoris Fosl. & Howe, Bull. N. Y. Bot. Gard. 4: 134. 



pi. 90. f. 1. 1906. 

 Melobesia (Pliostroma) Chamaedoris Fosl. & Howe, K. Xorske Vidensk. 



Selsk. Skr. 1908 n : 6. 1908. 



Encrusting and often completely encircling the stalks of Chamaedoris Peniculum, 

 from low-water mark (under shelving rocks) down to a depth of 40 meters (fide 

 Borgesen), Cave Cays, Exuma Chain : American Virgin Islands. Type from Cave 

 Cays. 



7. AMPHIROA Lamour. Xouv. Bull. Sci. Soc. Philom. 3: 186. 1812. 



Thallus usually distinctly flattened, 1-3 mm. broad, the 



branches 2-5 at a node, often patent or arcuate-deflexed. 1. A. Tribulus. 

 Thallus terete or subterete, 0.15-1.4 mm. in diameter. 



Thallus 0.15-0.6 mm. in diameter, usually yellowish or 

 pale rose when living, commonly dichotomous (rarely 

 3-5 branches at a node) ; nodes at the dichotomies, the 

 nodal cushions conspicuous, often protuberant or their 

 diameter equaling that of the segment, which is often 



enlarged at the nodes. 2. A. fragilissima. 



Thallus 0.451.4 mm. in diameter, bluish-violet when liv- 

 ing ; nodes mostly above the dichotomies, often obscure 

 or more or less deficient, the nodal cushions short and 

 their diameter Mh% that of the segments. 3. A. rigida antillana. 



1. Amphiroa Tribulus (Ell. & Soland.) Lamour. loc. eit. 



Corallina Tribulus Ell. & Soland. Xat. Hist. Zooph. 124. pi. 21. f. e. 1786. 



In shallow water. South Cat Cay and Watling's Island : -Cuba and Porto Rico. 

 Type from the West Indies. 



2. Amphiroa fragilissima (L.) Lamour. Hist. Polyp. 298. 1816. 



Corallina fragilissima L. Syst. Xat. 1: 806. 1758 [ed. 10]. 

 Amphiroa debilis Kiitz. Sp. Alg. 700. 1849. 



Variable as to diameter of the segments and in the presence or absence of 

 nodal enlargements of the segments, and possibly including two spcies. Whether 

 Linnaeus originally described the species from an actual specimen or relied 

 wholly upon Sloane's description and figure of a Jamaican plant is not alto- 

 gether clear. 



Forming mats, especially in association with Thalassia and Cymodocea in shal- 

 low bavs, common, New Providence, Berry Islands. Bimini, South Cat Cay, North Cat 

 Cay, Watling's Island. Atwood Cay, and Mariguana : Bermuda and Florida to Bar- 

 bados ; East Indies. Type "in Indiis " (Jamaica ?). 



3. Amphiroa rigida antillana Borg. Dansk Bot. Ark. 3 1 : 182. f. 171-173. 1917. 



In shallow water, often with A. fragilissima, but always distinct, South Cat Cay, 

 North Cat Cay, and Mariguana : Florida to Barbados. Type (of var.) from St. Croix. 



8. CORALLINA L. Syst. Xat. 1: 805. 1758 [ed. 10]. 



Rather vaguely and irregularly pinnate or subverticillate, the branches often few ; 

 segments of* main axes terete or subterete, 1.5-6 times as long 

 as broad. 1- C. cubensis. 



Pinnate or bipinnate, the rapidly tapering branchlets somewhat 

 penicillate or fasciculate ; segments of main axes distinctly flat- 

 tened, cuneate-obovate, or inversely deltoid, about as broad as 

 long 2. C. subulata. 



