124 



Chase — Notes on Genera of Panicese. TV, 



panicle and the reverse position of the spikelets, suggest an approach to 

 the unique North American Panicum ciliatissimum Buckl. The stipitate 

 spikelet of Leucophrys, however, with a joint between the glumes, and 

 the different arrangement of the silky pubescence on the second glume 

 and sterile lemma (a dense ring of long hairs across the middle of the 

 spikelet, an arrangement also found in Panicum nigropedatum, P. serra- 

 tum, P. argenteum, etc., and approached in several species of Eriochloa) 

 does not show a close affinity with P. ciliatissimum. Species intermediate 

 between them may be found, but without such intermediate species our 

 P. ciliatissimum finds a more natural place in Panicum. Study of more 

 material may show that Panicum argenteum and its allies should be placed 

 in Leucophrys. 



Rendle (1. c. ) places Leucophrys immediately before Tricholaena to 

 which he compares it. The silky spikelets resemble outwardly those 

 of Tricholaena but the indurated fruit and membranaceous, entire and 

 awnless second glume and sterile lemma indicate but remote relationship 

 to that genus. The two, however, probably belong closer together than is 

 indicated by their relative position in the sequence here given, but it must 

 be borne in mind that any lineal arrangement of that which is really 

 irregularly radiate must fail to show all but the closest relationship. 



12. Genus ERIOCHLOA H. B. K. 



Eriochloa H. B. K. Nov. Gen. & Sp. 1 : 94. pi. 30 and 31. 1816. Two 

 species are included, E. dislachya H. B. K. (1. c. pi. 30) "Cresc.it in 

 ripa Orinoci fluminis inter Santa Barbara et Esmeraldam," and E. 



polystac.hyaW. B. K. (1. c. pi. 31. ). Since 

 both are illustrated and are equally 

 covered by the generic description the first 

 species is here taken as the type of the 

 genus. A duplicate type of this, "Ex 

 herb. Humboldt," was examined in the 

 Berlin Herbarium. 



Helopus Trin. Fund. Agrost. 103. pi. 4. 

 1820. A single species, H. pilosus Trin. 

 (op. cit. 104) is included. Since the genus 

 only and not the species is described and 

 since no specimen is cited we should con- 

 sider the species based on Milium ramo- 

 sum Retz., which is cited as a synonym, 

 save for the fact that plate 4 shows an aristate lemma while Retzius 

 (Obs. Bot. 6:12. 1791) states that the " valvula exterior" is ma- 

 cronate only, and that Trinius later (Gram. Pan. 118. 1826) gives 

 Helopus pilosus Trin. as a synonym of Paspalum punctatum Fliigge 

 (Milium punctatum L. ), while Milium ramosum Retz. he gives as a 

 synonym of Paspalum annulatum Fliigge. In the Trinius Herbarium is 

 a specimen collected by Mikan in Brazil, which is marked in Trinius' 

 hand " Helopus pilosus in. Paspalum punctatum Fliigge." Whether or 



Fig. 4. 



Eriochloa dislachya. 



(Two views of spikelet and fruit x 



10 diam.) 



