192 Chase Notes on Genera of Panic eae. I. 



and membra naceous lignles. At maturity the panicles break away and 

 roll like tumble-weeds. Name from Xe7rr6s delicate and AcD^a border in refer 

 ence to the hyaline margins of the fertile lemma. 



Type. Panicum cognatum Schultes. 

 Leptoloma cognata (Schultes.) 



Panicum divergrns Muhl. in Ell. 1816. Sk. Bot. 1 : 130. not H. B. K.1815. 

 Specimen in Elliott herbarium in College of Charleston. 



Elliott gives " Muhl. Cat." without page as authority for this name ; in 

 Muhl. Cat. 9 (1813) divergens is a nomen nudum. 



Panicum divergens Muhl. 1817. Gram. 120. " Habitat in Carolina." 

 Specimen in the Muhlenberg herbarium in Philadelphia Academy of Nat 

 ural Sciences, marked " Elliott 353." In the same folio with this is a 

 specimen of Panicum Philadelphicum marked "M. 112b." 



Panicum cognatum Schultes 1824. Mant. 2 : 235. Muhlenberg's descrip 

 tion is copied and P. divergens Muhl. is cited as synonym, the name 

 changed, doubtless, because of P. divergens H. B. K., though this older use 

 of the name is not mentioned. Thus it is the second publication of P. 

 divergens Muh\. (that in Muhl. Gram.) on which Schultes bases his P. cog 

 natum. Hence the specimen in Muhlenberg's herbarium is the type. 



Panicum autumn ale Bosc. Spreng. 1825. Syst. 1 : 320. 



This name as used by American authors is synonymous with above, but 

 we have not seen Bosc's specimen. Sprengel (1. c.) places the description 

 of P. autnmnale next to that of P. divergens Muhl. The brief description 

 would apply to any Panicum with an effuse capillary panicle. It was not 

 known to Sprengel where the specimen came from ; " Patria?" he adds to 

 his description, and indicates he saw the specimen in the WiUdenow her 

 barium. 



The sheaths and blades of this species, especially the lower ones, are 

 often papillose pubescent, commonly so in Western specimens, though the 

 type is almost glabrous. Pringle 489, Chihuahua, Mexico, represents an 

 extreme form with slightly larger spikelets, having densely silky-pubescent 

 internerves, which would appear to be a distinct species except for the 

 fact that the inter-grades are more numerous than the extreme form. This 

 is the only species of this genus known in the northern hemisphere. Three 

 or four species are found in Australia. 

 Leptoloma divaricatissima (R. Br.) 



Panicum divaricalissimum R. Br. 1810. Prod. 192. Port Jackson, New 



Holland. 

 Leptoloma mac rate nium (Benth.) 



Panicum macratenium Benth. 1878. Fl. Australia 7 : 468. " Queensland, 



Rockhampton, O'Shanesy." 

 Leptoloma coenicola (F. Muell.) 



Panicum coenicolum F. Muell. 1855 in Trans. Viet. Inst. 45. Cudnaka, 

 S. Australia, F. Mueller. 



Panicum papposurn R. Br. Prod. 192, and P. nematostachyum Bailey 1903 

 in Bot. Bui. Dept. Agr. Queensl. 16 : 2, of which we have not seen speci 

 mens, probably belong here. The former is P. autumnale F. Muell. Fragm. 

 8 : 196, not Bosc, fide Bentham Fl. Australia 7 : 469. 



