1957] 



THE BOTANY OF THE GUAYANA HIGHLAND— PART II 



237 



Materials collected during the Chimanta-tepuf expeditions made independently 

 in 1953 by John J. Wurdack and Julian A. Steyermark, and the common expedition 

 conducted by them jointly in 1955, are reported in "Botany of the Chimanta 

 Massif" (Mem. N.Y. Bot. Gard. 9:000-000. 1956). New taxa described in the 

 Chimanta report, when the genus involved is treated herein, are "keyed out" in 

 this paper. 



Again we have the pleasure of acknowledging assistance given to us in the 

 prosecution of our activities. Transportation and port facilities have, as in the 

 past, been made available to us by Alcoa Steamship Company, Gulf Oil Corpora- 

 tion, Mene Grande Oil Company, National Bulk Carriers, Inc., and Sinclair Oil 

 and Refining Company. Johnson Motor Company has again provided 15-horse- 

 power and 25 -horsepower outboard motors for river exploration. Sears Roebuck 

 and Company continued to furnish equipment and supplies. Parke, Davis and 

 Company maintained our medical supplies at the most efficient level for tropical 

 exploration. 



The work of this program continues with the financial support of the National 

 Science Foundation. 



MUSCI 3 



Leucobryum martianum (Hornsch.) Hpe. 



VENEZUELA: Amazonas: Cerro Duida, Rio Cunucunuma. .On tree trunk, north 

 escarpment above Culebra, elev. 1400 m, Nov. 20, 1950, Bassett Maguire, R. S. 

 Cowan & John J. Wurdack 29610 A. 



Distribution: Central America, West Indies, northern South America. 



The above collection represents a rather striking form without any structural 

 differences but distinguishable at a glance by the purple coloration. I have in the 

 herbarium four other collections from the Cerro Duida region made by Steyermark 

 that show the same distinctive color tinge. 



Trichostomum duidense Bartr., sp. nov. 



Dioicum, dense caespitosum, caespitibus fuscescenti-viridibus. Caulis erectus, 

 simplex, dense foliosus. Folia sicca valde circinato-incurva, humida erecto- 

 patentia, 3~3.2 mm longa, e basi oblonga paulum latiore sensim lineari-lanceolata, 

 acuta, integerrima; marginibus planis; costa brevissime excurrente, dorso papu- 

 losa; cellulis laminalibus minutis, dense papillosis, basilaribus anguste rectan- 

 gularibus, incrassatis, infimae laxioribus. Seta 13-16 mm longa, tenuissima; 

 theca angusrissime cylindrica, erecta vel leniter curvata, 2.5*2.7 mm long, fus- 

 cescens. Caetera ignota. 



VENEZUELA: Amazonas: Cerro Duida, Rio Cunucunuma. On stones, Culebra 

 Creek, elev. 1500-1600 m, Nov. 21, 1950, Bassett Maguire, R. S. Cowan & John 

 J. Wurdack 29652. 



The long, slender, often slightly curved capsules are distinctive. Unfortu- 

 nately the fruit is all old and deoperculate so that the peristome characters are 

 not available, but definite vestiges of peristome-teeth have been observed in 

 several of the capsules examined. 



GRAMINE AE 4 



Among the grasses of the Guayana Highland, the genus Myriocladus is the 

 most remarkable. All the nineteen species known are endemic, and only one, M. 



3 By Edwin B. Bartram. 



4 By Jason R. Swallen; except Andropogon and Paspalum, by Ernest R. Sohns, and 

 Axonopus, by George Black. 



