250 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[Vol. 9. No. 3 



Thrasya guianensis Swallen, sp. nov. 



Perennis; culmi erecti, ramosi, ca. 90 cm alti; vaginae internodiis paulum 

 longiores vel breviores, ad summum pilosae marginibus ciliatae; ligula 1-2 mm 

 longa, fusca; laminae 8-18 cm longae, 4-6 mm latae, subattenuatae, dense 

 pilosae; inflorescentiae terminales et axillares; racemi 1 vel 2, 4-11 cm longi; 

 rachis 1 mm lata, marginibus scabra, pilis paucis rigidis longis; spiculae 1.6-1.8 

 mm longae, obtusae, pedicellis brevibus dense pubescentibus; gluma prima 0.3 

 mm longa, obtusa, enervis; gluma secunda obtusa fructu 1/3 brevior vel fructum 

 subaequans; lemma sterile fructum aequans, glabrum vel sparse pilosum; fructus 

 obtusus, albus, papillosus. 



Perennial; culms erect, branching from most of the nodes, about 90 cm high; 

 sheaths a little longer or shorter than the internodes, pilose toward the summit, 

 the margins ciliate; ligule 1-2 mm long, brown; blades 8-18 cm long, 4-6 mm 

 wide, subattenuate, somewhat narrowed toward the base, densely pilose; inflo- 

 rescences terminal and axillary, with usually solitary or sometimes 2 racemes 

 4-11 cm long; rachis 1 mm wide, the margins scabrous and with scattered long 

 stiff hairs; spikelets 1.6-1.8 mm long, obtuse, the short pedicels densely pu- 

 bescent; first glume 0.3 mm long, obtuse, nerveless; second glume obtuse % as 

 long to nearly as long as the fruit; sterile lemma equaling the fruit, glabrous or 

 occasionally sparsely pilose; fruit obtuse, white, strongly papillose. 



TYPE: dominant caespitose grass of burnt savanna, Sagaraimadai, alt. 550 m, 

 Upper Mazaruni River, British Guiana, November 16, 1951, Bassett Maguire & 

 D. B. Fanshawe 32621A; U. S. National Herbarium No. 2,078,799. 



Axonopus rivularis Black, sp. nov. 



Perennis, foliis laxis; culmi 75-90 cm longi, 1-2 mm crassi, teretes vel vix 

 compressi; nodi 1-2, pilosi; vaginae 10-35 cm longae, superiores longiores, 



1- 3 mm latae, dorso rotundatae, cataphyllis 1-3 mm longis, ad basin nonnumquam 

 a culmis solutae, internodiis breviores, glabrae, summo ciliatae; ligula 0.3-0.4 

 mm longa, ciliata; laminae 10-30 cm longae, 0.5-1.0 cm latae, planae, lineari- 

 lanceolatae nervo mediano prominulo, longe-acuminatae, ad basin dense pilosae, 

 subtus sparse pilosae pilis longis, supra glabrescentes; inflorescentiae ter- 

 minales, pedunculis 2-4, ca. 30-40 cm longis; paniculae 15-25 cm longae; racemi 



2- 3, divergentes, ca. 10-20 cm longi, axilla dense molliter pilosa, interdum pilis 

 longioribus adspersis; rhachis 0.3-0.4 mm lata, viridescens, glabra vel scabrida, 

 flexuosa, in 25 mm 10-11 spiculis praedita; spiculae 3.2-3.3 mm longae, 0.7-0.8 

 mm latae, lineari-lanceolatae, obtusae; gluma et lemma sterile aequalia, 5-7- 

 nervia* nervis prominulis ad apicem productis, inter nervos adpresse et sparse 

 pilosa; pedicellus brevissimus; flosculus 2.0-2.1 mm longus, albidus, obtusus, ad 

 apicem dense breviter molliterque pilosus. 



Erect or spreading perennial, leafy throughout, the foliage lax; culms 75-90 

 cm tall, 1-2 mm thick, terete or slightly compressed, often reddish or purplish; 

 nodes 1-2, 1-3 mm long, appressed-pilose, often glabrescent; sheaths 10-35 cm 

 long, the upper ones longest, 1-3 mm wide, not keeled, sometimes remote from the 

 culm, glabrous or ciliate toward the summit, shorter than the internodes, some re- 

 duced to cataphylls 1-3 cm long; ligule 0.3-0.4 mm long, ciliate, the crown often 

 longer than the base; collar hairy on either side, the wedge-shaped area distinct; 

 blades 10-30 cm long, 5-10 mm wide, broadest at the middle, flat, acuminate, the 

 midnerve prominent, the margins scabrous, long-ciliate at the base, densely hairy 

 on the under surface, glabrescent above with a few long hairs just above the 

 ligule, the base equal to the width of the sheath or slightly broader; inflorescence 

 terminal; peduncles 2-4, 15-25 cm long, usually red-tinged; panicles 15-25 cm J 



