THE BRYOLOGIST 



Vol. XXIV September, 192 i No. 5 



MOSSES FROM BRITISH GUIANA AND DOMINICA, LESSER 

 ANTILLES, COLLECTED BY MISS E. F. NOEL IN 1914 



(With Plate IV) 



R. S. Williams 



The first eleven species listed are from Kaieteur Falls, 011 the Potaro river, 

 a branch of the Essequibo and a region but little known botanically. These 

 falls can only be reached, it is said, during the dry season when the river is low 

 and then only with considerable difficulty. They are among the scenic wonders 

 of British Guiana, the Potaro river being 120 feet wide in the dry season and 400 

 feet in the wet, and having a sheer plunge of some 740 feet into the canyon below. 



From Kaieteur Falls 



Leucubryum crispiim C. M. 84. 



Leucobryum Martianum (Hsch.) Hampe 82 & g6. 



Calymperes leucophyllum Schwaegr. 97. 



Macromitrium trinitense sp. nov. 



Evidently dioicous: primary stems creeping, bearing more or less numerous, 

 curved branches i to 3 cm. high; stem-leaves narrowly lanceolate, 5 to 7 mm. long, 

 somewhat serrulate half way down or more, the slender flexuous points often 

 twisted when dry; costa slender, 25 to 28 /jl wide near the base, not excurrent, the 

 very narrow leaf-blade extending to the apex; cells of leaf elongate, in rows with 

 furrows between, mostly unipapillate on both sides from near the apex to the 

 base; the median cells variable, with prominent papillae and broad lumen or 

 in the older leaves with papillae often indistinct and lumen very narrow; cell- 

 walls somewhat unequally thickened throughout; outer perichaetial leaves 

 similar to those of the stem, the 2 or 3 inner leaves one-third to one-half as long, 

 more or less oblong, abruptly narrowed and irregularly serrulate above to a 

 short, mostly entire point; seta smooth, 6 to 9 mm. long; capsule smooth, obovate, 

 tapering into a somewhat ribbed neck, when dry becoming almost globose, about 

 I mm. long without the lid, the slender-beaked lid of about the same length; 

 annulus none; peristome evidently double (imperfect or very young); spores 

 (immature) not quite smooth, 22 to 25 n in diameter; calyptra without hairs, 

 somewhat scabrous above, slit into numerous segments below. 



1 The July number of The Bryologist was printed Janxiary 9, 1922. 



