404 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN tyol. 9, No. 3 



mit Camp, February 2, 1955, Julian A. Steyermark & John /. Wurdack 327. The 

 spike lets of the latter specimen average somewhat smaller than those of the type. 



Ischaemum arenosum Sohns, sp. nov. (Fig. 75.) 



Perenne; culmi erecti, usque ad 60 cm alti; vaginae internodiis longiores, 

 glabrae; ligula 1.5 mm longa, membranacea; laminae 2-10 cm longae usque ad 

 7 mm latae, planae, prope basin longe pilosae, ceteroqui glabrae; racemi solitarii, 

 5 cm longi (vel longiores), erecti, pilosi; articuli ca. 4.5 mm longi, triquetri, 

 marginibus pilosi; spiculae sessiles 4.5 mm longae; gluma inferior 3.5-4.5 mm 

 longa, 9-nervia, dorso pilosa, apice bidentata; gluma superior 3.5-4.5 mm longa, 

 3-nervia, carinata, dorso prope summitatem pilosa, ceteroqui glabra; lemma sterile 

 ca. 3-5 mm. longum, membranaceum, 3-nervium; palea lemma sterile subaequans, 

 bicarinata, carina superne valide scaberrima; stamina 3; antherae breves; ovarium 

 nullum; lodiculae 2, 0.4-0.6 mm longae; lemma fertile ca. 3 rnm. longum, 3 (-5)- 

 nervium, membranaceum; arista 3-5-6 cm longa, laxe torta; palea lemma fertile 

 aequans, bicarinata, membranacea; stamina 3; antherae 0.8-1 mm longae; lodiculae 

 2, 0.4-0.5 mm longae; spiculae pedicellatae 3.4-5.5 mm longae, breviter articu- 

 latae; gluma inferior 3.4-5.5 mm longa, carinata, 9-nervia, dorso leviter pilosa; 

 gluma superior primam aequans, 3 (-5)-nervis, carinata, dorso prope summitatem 

 leviter pilosa; lemma sterile 3-4 mm longum, membranaceum, 1 (-3)-nervium, 

 glabrum; palea lemma sterile aequans vel longior, valde bicarinata, carinis 

 scaberrimis; stamina 3; antherae 0.9-1 mm longae; ovarium nullum; lodiculae 2, 

 0.3-0.5 mm longae; lemma fertile 2.5-3 mm longum, 3-nervium, membranaceum; 

 arista 4-5.5 mm longa, laxe torta; palea 2.1-3 mm longa, membranacea; stamina 

 3; lodiculae 2, ca. 0.8 mm longae, truncatae. 



Perennial; semidecumbent at the base and rooting at the nodes, culms then 

 erect to 60 cm tail, many-noded, sometimes the upper nodes of young culms 

 pubescent; sheaths longer than the internodes, glabrous; ligule 1.5 mm long, 

 membranous; blades 2-10 cm long, up to 7 mm wide, flat, papillose-pilose at the 

 base behind the ligule, otherwise glabrous, the nerves white and prominent on the 

 upper surface; racemes solitary, 5 cm or more long, erect, pilose; rachis joints 

 about 4.5 mm long, 3-angled, ascending-pilose on the angles; sessile spikelet up 

 to 4.8 mm long, shortly pedicellate; first glume 3.5-4.5 mm long, 9-nerved, pilose 

 over the back and on the margins, the tip slightly bidentate; second glume as 

 long as the first, 3 (-5)-nerved, keeled, pilose on the back toward the tip, other- 

 wise glabrous; lower floret 3-3.5 nun long; sterile lemma about 3.5 mm long, thin, 

 faintly 3 (-5)-nerved; palea as long as or longer than the lemma, firmer in texture, 

 2-keeled, the keels strongly scaberulous toward the tip; stamens 3, the anthers 

 small* and apparently non-functional; pistil none; lodicules 2, 0.4-0.6 mm long; 

 fertile lemma about 3-3.4 mm long, 3 (-5)-nerved, the nerves converging into the 

 base of the awn, the awn 3.5-6 mm long, loosely twisted, its base dark-brown, the 

 median nerve prominent, the terminal portion antrorsely scabrous; palea as long 

 as the lemma, 2-keeled, membranous; stamens 3, the anthers 0.8-1 mm long; 

 ovary developed, stigmas plumose, the styles free to the top of the ovary; lodicules 

 2, 0.4-0.5 mm long; pedicellate spikelet 3.4-5.5 mm long, the joint 0.5-0.8 mm 

 long, densely short-pilose; first glume 3-4-5.5 mm long, keeled, 9-nerved, sparingly 

 pilose over the back; second glume as long as the first, 3 .(-5)-nerved, keeled, 

 sparingly pilose over the back toward the tip; sterile lemma 3-4 mm long, membra- 

 naceous, 1 (-3)-nerved, glabrous; palea as long as or 0,1-0.5 mm longer than 

 the lemma, firmer, 2-keeled, scaberulous on the keels; stamens 3, the anthers 

 0.9-1 mm long; ovary 0; lodicules 2, 0.3-0.5 mm long; fertile lemma 2.5-3 mm 

 long, 3-nerved, the nerves converging into the base of the awn, membranaceous; 



