[From the Bulletin op the Toreey Botanical CLVB42: 393-404. 27 Jy 1915. 



Mosses from the west coast of South America 



R. S. Williams 

 (with plates 21-25) 



A list of mosses collected by Dr. and Mrs. J. N. Rose in Peru, 

 Bolivia and Chile, July to October, 191 4, while on a trip under- 

 taken chiefly for the purpose of obtaining Cactaceae. 



This collection of 41 mosses, coming as it does largely from the 

 dry cactus region of the west coast of South America, contains for 

 its size an unusually large number of interesting species. 



Campylopus incrassatus (Kze.) C. M. 

 Peru: near Mollendo, i8gg6. 



Campylopus peruvianus sp. nov. 



Sterile: plants in compact cushions with more or less branching 

 stems, radiculose below, and 10-15 mm. high; leaves ovate-lanceo- 

 late, entire except at the apex, closely imbricate, erect-appressed 

 when dry, somewhat spreading when moist, the upper rather 

 larger, 3-4 mm. long, mostly with a short, rough, hyaline point 

 rarely more than 0.5 mm. long; costa about one half the width of 

 the leaf in the lower part, in cross-section showing stereid bands 

 above and below the guide cells and bearing on the back about 24, 

 not serrate, lamellae up to 4 cells in height; alar cells enlarged, 

 mostly pale, extending to the costa; marginal cells of lower leaf 

 narrow and elongate, forming a narrow, hyaline border sometimes 

 extending half way up the leaf; the median cells mostly 

 short-rhomboidal, those just above the alar, short rectangular, all 

 with slightly thickened not pitted walls. 



Peru: near Mollendo, August, i8ggy. 



Astomum chilense sp. nov. 



Dioicous, the inconspicuous male flow^ers containing 5 or 6 

 antheridia with few paraphyses, enclosed by 2 or 3 very small 

 inner perigonial leaves; the outer leaves being scarcely differen- 

 tiated : plants in rather compact mats with simple stems about I 

 mm. high, bearing radicles at base; stem-leaves up to 1.5 mm., 

 rarely 2 mm. long, ovate-lanceolate, more or less folded and 

 crispate when dry, rather widely spreading when moist, with flat, 

 entire margins; costa excurrent into a short apiculus, in cross- 



393 



