1963] 



BOTANY OF THE GUAYANA HIGHLANDS PART V 



L9 



Distribution. Known otherwise by Steyermark 58211, collected at the type 

 locality. 



15. Xyris atriceps Malme, Bull. Torrey Club 58: 325. 1931. 



Key to the Subspecies of Xyris atriceps 



1. Floral bracts broadly obovate or orbicular, 3-4 mm long, strongly roughened and 

 the margins quickly becoming strongly pectinate-lacerate; spikes broadly turbinate, 

 ca. 7 mm long. subsp. atriceps. 



1. Floral bracts oblong, or oblanceolate-oblong. 



2. Bracts oblong, 6-7 mm long, essentially smooth, tardily becoming lacerate; spikes 



narrowly turbinate, ca. 10 mm long. subsp. neblinensis. 



2. Bracts lanceolate-oblong, 4-5 mm long, strongly roughened, the margins quickly 



becoming pectinate-lacerate, heads 4-6 mm long. subsp. chimantensis. 



Xyris atriceps subsp. atriceps. 



Herbae cespitosae ; spica late turbinata, ca. 7 mm longa ; bracteis late obovatis 

 vel orbicularibus, 3-4 mm longit, valde rugulosis, marginibus mox pectinato- 

 laceratis. 



Type. Forming tussocks, alt. 6700 ft, Cerro Duida, Amazonas, Venezuela, 

 G. H. H. Tate 688 (holotype NY). 



Distribution. Initially collected by Tate and subsequently by Steyermark 

 (No. 58185) from the southern summits of Cerro Duida. The Steyermark speci- 

 mens are immature. 



Xyris atriceps subsp. neblinensis Maguire & Smith, subsp. nov. 



Herbae cespitosae ; foliis 4-5 dm longis, fere teretibus, 0.5-0.6 mm diam., 

 basin versus valde scabris, apice obtuso; vaginis atro-castaneis, 3-5 cm longis, 

 laevibus vel dorso paulo scabris, ligula 1-2 mm longa ; scapo 5-6 dm alto, tereti, 

 ca. 0.8 mm diam., sublaevi ; vagina scapi ca. 10 cm longa, lamina 2-3 cm longa 

 praedita; spica anguste turbinata, ca. 10 mm longa; bracteis oblongis, 6-7 mm 

 longis, laevibus, ad marginem anguste scariosis et tarde pectinato-laceratis ; se- 

 palis lineari-subfalcatis, marginibus apicem versus paupere ciliolatis. 



Type. In clumps, leaves terete, locally abundant, east escarpment of upper 

 Canon Grande Basin, alt. 1900 m, 15 Dec 1957, Cerro Neblina, Amazonas, Vene- 

 zuela, Bassett Maguire, John J. Wurdack & Celia K. Maguire 42416 (holotype 

 NY, isotype US). Paratype. West Escarpment, alt. 1800 m, Cerro Neblina, 

 Maguire, Wurdack & Bunting 37244, Maguire, Wurdack & Maguire 42342. 



Distribution. Tussock-forming, abundant and generally distributed on sum- 

 mit savannas, this dominant herb was never observed to be freely flowering. 

 Known only from Neblina. 



Xyris atriceps subsp. chimantensis Maguire & Smith, subsp. nov. 



Herbae ex comparatione parvae; foliis 12 cm haud superantibus ; scapo ple- 

 rumque 15-20 cm longo ; spica ca. 6 mm longa ; bracteis lanceolatis, plus minusve 

 carinatis, valde rugosis, marginibus profunde pectinato-incisis. 



Type. Sheaths blackish-purple at base, culms purple-black, involucre black- 

 ish, petals deep yellow, 5 mm long, locally frequent, Rio Tirica, alt. 1925 m, 

 5 Feb 1955, Chimanta Massif, Bolivar, Venezuela, Julian A. Steyermark & John 

 J. Wurdack 485 (holotype NY, isotype US). 



