1957] 



THE BOTANY OF THE GUAYANA HIGHLAND— PART II 



267 



Ichnanthus tectus and /. angustus are related to /. serratus Swallen and /. 

 longifolius Swallen described from Mt. Duida. These four species are similar in 

 having blades with irregular scabrous margins and stipitate fruit, the articulation 

 on the ventral side, the scar circular. They are differentiated as follows: 



Blades 4-5 mm wide, about 30 cm long; panicles lax, the pedicels slender, usually 



much longer than the spikelets. /. serratus. 



Blades 8-11 mm wide, usually more than 50 cm long; panicles stiff, the pedicels 

 usually much shorter than the spikelets. 

 Blades attenuate to a fine point, smooth and shining; spikelets 3-4-3.6 mm long. 



/. longifolius. 



Blades acuminate, not shining; spikelets 4-5 mm long. 



Spikelets 5 mm long; blades long-attenuate to the base; panicle branches 



spreading. /. tectus. 



Spikelets 4 mm long; blades narrowed but not long-attenuate to the base; 



panicle narrow, the branches ascending. /. angustus. 



Lasiacis acuminata Swallen, sp. nov. 



Culmi erecti, 2 m alti, ramis gracilibus usque ad 50 cm longis; ramorum vagi- 

 nae 3-4 cm longae internodiis longiores, pilosae vel ad summum hirsutae, vel 

 subglabrae, collo dense villosae margine ciliatae; ligula firma, 0.4-0.8 mm longa; 

 laminae 7-12 cm longae, 5-10 mm latae, acuminatae, dense pubescentes vel 

 pilosae; paniculae 9-17 cm longae, ramis solitariis adscendentibus, scabris, 

 paucifloris, inferioribus 6-8 cm longis; spiculae 3.6-3.8 mm longae, pedicellis 

 5-15 mm longis, scabris. 



Culms erect, 2 m high, with slender branches as much as 50 cm long; sheaths 

 of the branches mostly 3-4 cm long, longer than the internodes, densely pilose or 

 hirsute toward the summit or nearly glabrous, densely villous on the collar, one of 

 the margins ciliate; ligule firm, 0.4-0.8 mm long; blades 7-12 cm long, 5-10 mm 

 wide, acuminate, densely pilose or pubescent on both surfaces; panicles 9-17 cm 

 long, the solitary branches narrowly to widely ascending, few-flowered, scabrous, 

 the lower ones 6-8 cm long; spikelets 3.6-3.8 mm long, the pedicels 5-15 mm 

 long, rarely longer or shorter, scabrous. 



TYPE: on Isla Carestia at Saltos Carestia y Gallo (5 km north of Sanariapo), 

 alt. 100-120 m, Great Rapids of the Orinoco, Amazonas, Venezuela, November 11, 

 1953, Bassett Maguire, John J. Wurdack & George S. Bunting 361 7 1; U. S. National 

 Herbarium No. 2,182,157. 



Pariana violascens Swallen, sp. nov. 



Perennis culmis biformibus; culmi steriles 40-60 cm alti, summo 3-6 foliosi; 

 vaginae glabrae in ore fimbriatae setis usque ad 2 cm longis; laminae 11.5-18 cm 

 longae, 3-4 cm latae vel superiores minores, subacuminatae, ceruleo-virides, 

 subtus granulosae; culmus fertilis 30 cm longus, adscendens, vagina suprema 

 elongata; inflorescentia 6 cm longa, ca. 7 mm lata, pallida, spicularum fasciculis 

 8-9 mm longis, pedicellis spicularum mascularum 4 mm longis, basi dense pilosis; 

 spiculae masculae: glumae acutae lemmate ca. 1/2 breviores, una lata, decurrens, 

 2-nervis, altera angusta, enervis, vel uterque latae, tenuiter ciliatae; lemma 4.5- 

 5 mm longum, 1.5-1.8 mm latum, acutum, granulosum, in parte superiore reticu- 

 latum. 



Leafy culms 40-60 cm high with 3-6 leaves at the summit, without a smaller 

 blade below; sheaths glabrous, the throat fimbriate, the bristles as much as 2 cm 

 long, but usually shorter; blades 11.5-18 cm long, 3-4 cm wide, or the upper ones 

 smaller, rather abruptly and asymmetrically subacuminate, bluish-green, granular 



