T. Holm — Studies in ihe Cyperacece. 455 



Xerochlmnce nob. 

 Spikes , man J, rather large, in a dense-flowered, spicate inflor- 

 escence, sessile, mostly contiguous, androgynous ; bracts often 

 conspicuous, setiform ; scales brownish ; perigynia mostly erect, 

 seldom spreading, brown, stipitate or sessile, broadly ovate to 

 orbicular, plano-convex, nervose, more or less winged, serrulate, 

 tapering into a distinct, bidentate beak ; stigmata two, seldom 

 three. Some species show tendency of becoming dioecious. 



Centrales: C. divisa Huds., marcida Boott, Sartwelli Dew., dis- 

 ticha Huds., repens Bell., arenaria L., arenicola Fr. et Sav., 

 Kirkii Petrie, potosina Hems), Schreberi Schr., brizoides L. 



Desciscentes : C. inversa R. Br., resectans Cheesem., Douglasii 

 Boott, macrocepliala Willd. 



Psyllophorm Lois, ex p. 

 Spike single, brownish to light green, androgynous, lax and 

 few-flowered, the pistillate portion squarrose at maturity ; 

 scales oblong, acuminate, those of the pistillate flowers decidu- 

 ous ; perigynium shining brown to greenish, erect, but reflexed 

 at maturity, membranaceous, elliptical, shortly stipitate, obso- 

 letely two-nerved, glabrous, tapering into a beak with hyaline, 

 obliquely cut orifice ; stigmata two. 



SebetatoB : C. pulicaris L., macrostyloyi Lapeyr., sagittifera Lowe. 



Phcenocarpce nob. 

 Spikes numerous, small, in a dense-flowered panicle or spi- 

 cate inflorescence, sessile, contiguous, androgynous ; bra(its 

 short, filiform ; scales brownish; perigynia erect or somewhat 

 spreading, ovate to orbicular, shining brown, spongious at base, 

 plano-convex, nervose, with thin margins and a serrulate, 

 bidentate beak ; stigmata two. 



Centrales: C. paradoxa Willd., teretiuscula Goodi., paniculata 

 L., appressa R. Br., virgata Soland., decomposita Muehl. 



Athrostachym nob. 

 Spikes several in a dense-flowered head, or the lower ones 

 somewhat remote, sessile, gynsecandrous ; bracts seldom con- 

 spicuous ; scales brownish ; perigynia erect, lanceolate to ovate 

 or suborbicular, brown, plano-convex, nervose, more or less 

 broadly winged with a long, serrulate, obliquely cut or biden- 

 tate beak ; stigmata two. 



Centrales: C. tribaloides Wahl., Craiofordii Fern., scoparia Schk., 

 Mushing umensis Schw., leporina, L., athrostachya Olney, 

 festiva T>qw., petasata Dew., pinetoruin Liebm., siccata 

 T>^v^.^ pratensis Drej., adusta Boott, haloides Petrie, vlrldis 

 Petrie, ceiiea Fern., Liddonii Boott. 



Desciscentes : C. Bonplandli Ktb.* 



* =illota Bailey. 



