1957] 



THE BOTANY OF THE GUAYANA HIGHLAND— PART II 



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ascending, few-flowered; spikelets very long-pedicellate, 1.4-1.5 mm long, 

 elliptic, glabrous; first glume narrow, acute or subobtuse, half as long as the 

 spikelet; second glume and sterile lemma obtuse, the glume 3/4 as long as the 

 fruit, the lemma exceeding it; fruit acute, white, striate. 



TYPE: occasional on savanna on summit of Cerro Guanay, alt. 1800 m, 

 Amazonas, Venezuela, February 4, 1951, Bassett Maguire, Kathleen D. Phelps, 

 Charles Bo Hitchcock & Gerald Budowski 31751; U. S. National Herbarium No. 

 2,078,752. 



Panicum vigoratum Swallen, sp. nov. 



Perenne rhizomatosum; culmi robusti, erecti, 1.5 m alti; vaginae internodiis 

 1/3-1/2 breviores, deciduae, glabrae, in ore pilosae; ligula 0.5-1 mm longa, 

 ciliata; laminae 40-45 cm longae, 5-6 mm latae, attenuatae, marginibus scabris- 

 simae; panicula 20 cm longa, 2 cm lata, ramis anguste adscendentibus, scaber- 

 ulis; spiculae 2.5 mm longae, binae, appressae, glabrae; gluma prima ca. 2 mm 

 longa, abrupte acuminata; gluma secunda et lemma sterile aequalia fructu lon- 

 giora; antherae 1 mm longae. 



Perennial; culms coarse, erect from strong rhizomes, about 1.5 m high; 

 sheaths mostly half to two thirds as long as the internodes, loose, somewhat 

 divergent or rather readily deciduous, glabrous, hairy at the throat; ligule 0.5- 

 1 mm long, ciliate; blades firm, 40-45 cm long, 5-6 mm wide, attenuate, narrowed 

 toward the base, the margins very scabrous; panicle (immature) 20 cm long, 2 cm 

 wide, partly enclosed in the sheath, the slender branches rather narrowly ascend- 

 ing, scaberulous; spikelets 2.5 mm long, glabrous, appressed, in pairs, unequally 

 pedicellate; first glume broad, clasping, abruptly acuminate, about 2 mm long; 

 second glume and sterile lemma equal, pointed beyond the fruit; anthers 1 mm 

 long. 



TYPE: abundant and dominant around savanna margins, Sabana de Santo, 

 Rio Guaviarito, Cerro Guanay, Amazonas, Venezuela, January 23, 1951, Bassett 

 Maguire, Kathleen D. Phelps, Charles B. Hitchcock & Gerald Budowski 31601; 

 New York Botanical Garden. 



This species is allied to Panicum altum Hitchc. & Chase which differs in 

 having larger spikelets, the first glume less acuminate, and anthers 1.5 mm long. 



Panicum deciduum Swallen, sp. nov. 



Perenne; culmi erecti usque ad 4 m alti, glabri, ex nodis intermediis ramis 

 elongatis; vaginae internodiis multo breviores, glabrae, deciduae; ligula ca. 1 mm 

 longa, ciliata; laminae 9 cm longae, 8 mm latae, acuminatae, subtus basi pilosae, 

 marginibus minute scabrae; ramorum laminae breviores; paniculae 3-7 cm longae, 

 1-3 cm latae, densae, ramis paucis adscendentibus usque ad 4 cm longis; spi- 

 culae brevipedicellatae, 3-3.2 mm longae, villosae; glumae aequales, acutae; 

 lemma sterile acutum glumis paulo brevius; fructus stipitatus, 1.5 mm longus, 

 acutus, albus, glabrus, lucidus. 



Perennial; culms erect, apparently without rhizomes, as much as 4 m high, 

 bearing long branches from the middle nodes, glabrous; sheaths very much shorter 

 than the internodes, loose, readily deciduous, glabrous, ligule about 1 mm long, 

 ciliate; blades of the midculm about 9 cm long, 8 mm wide, acuminate, pilose on 

 the undersurface at the base, the margins minutely scabrous, the blades of the 

 branches gradually smaller; panicles 3-7 cm long, 1-3 cm wide, rather dense, the 

 few branches stiffly ascending, not more than 4 cm long; spikelets short-pedicel- 

 late, 3-3.2 mm long, obscured by the long silky hairs; glumes equal, acute; ster- 



