NEW MYXOrHYCKAK FROM TOIITO Ul(!0 



79 



Growing on rocks at a water reservoir, Rio Piedras, no. 106, 

 type. 



The closest atifinities of this species of Scytonema apparently 

 are 8. tenuissimum Sclmiidle, a smaller species with thinner 

 sheath, and 8. intermedium De Wild., a larger species. 



Scytonema guyanense minus var. nov. 



Filaments 12-18 n diam., long, flexuous, forming a thin, floc- 

 cose stratum ; trichomes up to 13 \x diam. at the apices, 6-8 n in 

 older parts ; cells cylindrical, or slightly torulose at the apices, 

 quadrate or less at the apices of the trichomes, 2-4 times as 

 long as the diameter in the older parts, homogeneous or with a 

 few refringent granules ; sheath slightly lamellose, lamellae not 

 diverging. 



Growing on lava between Arecibo and Utuado, no. 1455, type. 



Variety minus, as diagnosed above, differs from the species 

 chiefly in having on the average smaller filaments, thinner and 

 less lamellose sheaths, and longer and narrower cells in the main 

 body of the filament. 



Scytonema ocellatum purpureum var. nov. 



Filaments forming a pulvinate or floccose stratum 1-2 mm. 

 thick, 1-1.5 mm. long, I'^IS m diam.; cells homogeneous, pur- 

 plish or pale violet, subquadrate to 2 times as long as the diam- 

 eter; otherwise as species. 



Growing on soil, Coamo Springs, no. 292 c, type ; on soil in a 

 waterfall, about twelve kilometers north of Ponce, no. 1686. 



Scytonema ocellatum majus var. nov. 



Filaments 18-22 |j diam., about 1 mm. long ; cells cylindrical, 

 purplish gray; sheath thin, firm, homogeneous, smooth, brown; 

 branching both single and geminate. 



Growdng on limestone at Hacienda, Laguna Tortuguero, no. 

 867, type ; on rocks by a stream near Maricao, no. 1157. 



Scytonema ocellatum constrictum var. nov. 



Filaments much contorted, 15-19 |j diam. ; trichomes 12-14 jj 

 diam., heterocysts subspherical to much compressed, frequently 

 of less diameter than the trichomes, the filament being con- 



