578 



CERAMIACEAE. 



Family 12. CERAMIACEAE. 



1. SPERMOTHAMNION Areseh.; Fries, Siimma Veg. Scand. 127. 1845. 



Cells of erect filaments mostly 10-20 ^ in diameter, 3-6 times as long as broad; 

 tetrasporangia on 1— 4-celled pedicels ; plants usually grow- 

 ing on Galaxaura. 1. s. investiens. 

 Cells of erect filaments mostly 20-40 /^ in diameter, 2-5 times 

 as long as broad. 

 Vinaceous-purple or Indian lake, on Godium, manifestly 



repent. 2. 8. gorgoneum. 



Usually dark vinaceous-brown, under shelving rocks and on 



Jania, Galaxaura, etc., intricate, less manifestly repent. 3. 8. speluncarum. 

 Cells of erect filaments 40-65^ in diameter, 5-1.5 times as long 

 as broad: terminal cells clavate, 20-40^ in diameter, walls 

 of all cells 6-14 u thick ; tetrasporangia terminal, often more 



or less corymbose; plants growing on rocks. 4. 8. macromeres. 



Cells of erect filaments 50-115 ^ in diameter, 3-7 times as long 

 as broad, their walls 5-40 u thick; terminal cells commonly 

 cylindric, often only 12-15^1 in diameter, their walls 1-2 it 

 thick ; tetrasporangia at nodes, solitary or more commonly 

 several and unilaterally glomerate or subverticillate ; plants 

 on or with other algae. 5. 8. gijmnocarpum. 



1. Spermothamnion investiens (Cronan) Vickers, Ann. Sci. Nat. Bot. IX. 1: 



64. 1905. 



Callithamnion investiens Crouan; Schramm &• Maze, Alg. Guad. 7. 1865 

 [not seen]. 



On Galaxaura flagelliformis, G. suhverticillata, and G. comans, and on and with 

 Jania (growing on Sargassum), Great Bahama, Watling's Island, Mariguana, and 

 Caicos Islands : — Bermuda to Barbados. Type from Guadeloupe. 



2. Spermothamnion gorgoneum (Mont.) Bornet; Vickers, Ann. Sci. Nat. Bot. 



VIII. 4: 305. 1897. 



Callithamnion gorgoneum Mont. Ann. Sci. Nat. Bot. IV. 8: 289. 1857. 



On Godium isthmocladum. Berry Islands : — Bermuda to Barbados ; Canary Islands 

 and Cape Verde Islands. Type from island of St. Nicholas, Cape Verde Islands. 



3. Spermothamnion speluncarum (Collins & Hervey) M. A. Howe, comb. nov. 



Bliodocliorton speluncarum Collins & Hervey, Proc. Am. Acad. 53: 148. 

 1917. 



Variable in length of cells and thickness of the cell-walls; cells mostly 2-4 

 times as long as broad, but occasionally as much as 8 times; cell-walls usually 

 3-6^ thick, but ranging up to 12 /^ thick; tetrasporangia occurring mostly on 

 the lower part of the main erect filaments, solitary or rarely two (opposite) on a 

 segment, ellipsoid or subglobose, 52-65 ^l in maximum diameter, subsecund, 

 sessile or on 1- or 2-celled pedicels; antheridial stands terminal, short-cylindric 

 or ovoid-ellipsoid, about 40 /* X 20-28 fi. Erect filaments sometimes tortuous 

 and intricate, forming intertangled cushions. Belated to the North-European 

 S. roseolum (Ag.) Pringsh., especially to the form occasional in herbaria under 

 the name Callithamnion repens Lyngb.,but filaments more intricate and flexuous, 

 more slender (commonly 22-39 /a vs. 35-55 /x), cells shorter (usually 2-4 times 

 vs. 3-8 times as long as broad), more often dolioform, and more often collabent. 



Under shelving rocks and on various algae {Ghamaedoris, Galaxaura, Jania, etc.) 

 and on sponges, in shaded situations, near low-water mark. Rose Island, Great Ba- 

 hama, North Cat Cay, Mariguana, and Great Ragged Island: — Bermuda. Type (ster- 

 ile) from Bermuda. 



4. Spermothamnion macromeres Collins & Hervey, Proc. Am. Acad. 53: 132. 



1907. 



On surf-beaten, sand-covered rocks at low-water mark. Berry Islands : — Bermuda. 

 Type from Bermuda. 



