I lilrhcnck — 77/r Crosses of llcncaii 221 



as I to 1.5 cm. lonj^, some in whorls, others scattered; spikelets in clusters of 3 at the ends of 

 the branches, the cluster 6 to 8 mm. lonsf, disarticulating from the jiedicel or branch by a long 

 oblique callus extending down one side as a brown appressed-hispidulous ridge 5 mm. long, the 

 callus forming a retrorsely bearded or barbed point to the fruit ; sessile spikelet excluding the 

 callus about 4 mm. long, acute, glabrous, hispidulous-scabrous on the margins alx)ve. and on the 

 keel of the second glume, the latter awned, the awn about 2 mm. long ; sterile lemma nearly as 

 long as the first glume: fertile lemma rather narrow, taj^ering into an awn 5 mm. long: grain 

 oblong, 2 mm. long; sterile spikelets on pedicels 2 to 3 mm. long, the ])edicel liis])idulous at the 

 summit: glumes acuminate or awn-pointed, about 5 mm. long, scabrous at the tip; lemmas about 

 equal, awnless, shorter than the glumes (fig. 107). 



Common and often dominant on the central plain of Oahu. (PI. XXXI, C.) 

 The detached fruits are ver\- troublesome as they work their wav into the clothing 

 by the barbed callus. Called by the Hawaiians pilipiliula. 



Rocky slopes and o])en rather dry grassland: probably introduced. Origi- 

 nally described from the East Indies. 



Kauai: Lihue, Forbes 734. Hanapepe River, Heller 2476. 

 Oahu: Schofield Barracks, Hitchcock 13931. Palolo Valley, Hitchcock T414.V 



Honolulu, Hitchcock 137 13. Koko, Mann & Brigham 34. Hauula, Farmer 7. 

 Molokai : I'ukoo, Hitchcock 15053. Above Kaluokoi, Rock 6179. 

 Hawaii: Hilo, Hitchcock 14171 ; Newell in 1917. 



49. HETEROPOGON Pers. 



Spikelets in pairs, one sessile, the other pedicellate, 1x)th of the lower few to several ]iairs 

 staminate or neuter, the remainder of the sessile spikelets perfect, terete, long-awned, the pedi- 

 cellate spikelets. like the lower, staminate, flat, conspicuous, awnless: glumes of the fertile 

 spikelet equal, coriaceous, the first brown-hirsute, infolding the second; lemmas thin and hyaline, 

 the fertile one narrow, extending into a strong bent and twisted brown awn; palea wanting: 

 glumes of the staminate spikelet membranaceous, the first green, faintly many nerved, asym- 

 metric, one submarginal keel rather Ijroadly winged, the other wingless, the margins inflexed, 

 the second glume narrower, symmetric ; lemmas hyaline ; palea wanting. Annual or perennial, 

 often robust grasses, with flat blades and solitary racemes terminal on the culms and branches ; 

 rachis slender, the lower part, bearing the pairs of staminate spikelets, continuous, the remainder 

 disarticulating obliquely at the base of each joint, the joint forming a sharp barbed callus below 

 the fertile spikelet, the i^edicellate spikelet reailily falling. 



I. Heteropogon contortus ( L. ) Beauv. ; Roem. & Schult. Syst. \'eg. 2:836. 1817. 



Andropogon contortus L. Sp. PI. 1045. 1753. 



Plants perennial, cespitose, without rhizomes ; culms erect, glabrous, 50 to 100 cm. tall ; 

 sheaths glabrous, compressed-keeled ; blades mostly folded, glabrous, 10 to 30 cm. long, 

 2 to 5 lum. wide when unfolded ; racemes excluding the awns 4 to 8 cm. long, somewhat falcate, 

 i-sided, green or tawny, the awns brown ; outer glumes 7 to 8 mm. long, more or less papillose- 

 hispid ; awn of fertile lemma about 10 cm. long, with two rather indistinct bends, the terminal 

 segment atout 5 cm. long (fig. no). 



Called by the Hawaiians pili grass and used by them to form the walls of 

 huts by binding to the frame. (PI. XXXI, A.) 



Open rocky slopes. Tropics of both hemispheres. Originally described from 

 India. 



Kauai : Nonou Mountains, Forbes 594a. Hanapepe Ri\er, Heller 2522. 



[123] 



