Chase — Notes on Genera of Panicese. TV. 



149 



glume and sterile lemma leathery-indurated and nearly as firm as the 

 fruit. Bluffia eckloniana Nees (which is referable to AUoteropsis) and 

 Alloteropsis semialata (R. Br.) Hitchc, especially the first, have sterile 

 lemmas subindurated like their fruits but the two glumes are similar. 

 The subindurated, mucronate fruit, the lemma margins membranaceous 

 and flat above, the palea free at the summit, further differentiate Scutachne 

 from Panicum. 



Scutachne dura (Griseb. ) Hitchc. & Chase. 



Panicum durum Griseb. Mem. Amer. Acad. n. ser. 8 : 533. 1862. This 



was published in Plantae 

 Wrightianae e Cuba orientali ; 

 the only citation given is 

 ' ' ( 1539 ) . " The type specimen 

 is in the Grisebach Herbarium. 



Scutachne amphistemon 



( Wright) Hitchc. & Chase. 



Panicum amphistemon Wright, 

 Anal. Acad. Cienc. Habana 8 : 

 207.1871. " Cerra de Mayan 

 abajo. [3464]." The type 

 specimen, collected by Wright, 

 in the Gray Herbarium, is 

 labeled " Mayari-abajo, Aug. 

 2, in small dense tufts." 

 These two species were placed 

 in the genus Alloteropsis Presl 

 by Hitchcock (Contr. Nat. 

 Herb. 12 : 211. 1909) but fur- 

 ther study has made this dis- 

 position of them appear an 

 unnatural one. Alloteropsis is unique among the Paniceae in having a 

 minute prolongation of the rachilla beyond the fertile palea. This is not 

 present in all specimens of A. semialata examined, though it seems to be 

 constant in Bluffia eckloniana, but its. usual presence, together with the 

 awn-tipped glumes and lemma, the glumes of like texture;- indicate a 

 relationship too remote from the Cuban species to justify retaining them 

 in Alloteropsis. 



24. Genus ISACHNE R. Br. 



Isachne R. Br. Prod. Nov. Holl. 196. 1810. The genus is based on a 

 single species, i". australis R. Br. collected by Brown in the vicinity of 

 Port Jackson, Australia. The type has not been examined, but there is 

 no reason to doubt that it is the common species of Australia and New 

 Zealand, known under this name. 



Isachne has usually been recognized as a valid genus ever since its pub- 



Fig. 13. 



Scutachne dura. 



(Two views of spikelet and fruit x 10 diam. ) 



