ME. a. BENTHAM ON GEAMINEiE. 81 



by a pappus-like ring of long hairs, give a very peculiar aspect ; 

 but precisely similar flowering glumes are observable in several 

 South- American species with very various habits. In the Euro- 

 pean S. pennata, Linn,, and a few other American as well as 

 Old-World species, the awn itself is (almost entirely, or for a short 

 distance above the base) plumose with long spreading hairs. 

 Lasiagrostis, Link (Achnaiherum, Beauv.), was proposed as a 

 genus for tlie European S. Calamagrostis, Wahlenb., and extended 

 by Nees and Trinius to several African and Asiatic species, only 

 differing from other small-flowered Stipce in the flowering glume 

 itself being plumose with spreading hairs, either below the middle 

 or in its whole length ; and in S. mongholica, Trin., forming the 

 genus Ptilagrostis of Grrisebacli, these hairs extend to halfway up 

 the awn. S. verticillata, Nees, from Australia, and Apera arundi- 

 nacea, Hook, f , from New Zealand, two plants closely resembling 

 each other, though specifically distinct, connect Stipa with Mueh- 

 lenbergia. They have the inflorescence and small spikelets of the 

 latter genus ; and in B. verticillata the awn is generally persistent, 

 though the articulation is distinctly traceable on the flowering 

 glume ; in 8. arundinaeea the awn is very deciduous ; in this 

 species there is usually but one stamen, whilst in S. verticillata 

 there are the normal three. S. rariflora {MueWenhergiarariflora, 

 Hook, f.), from Antarctic America, is another species closely 

 allied to the above two ; and all three appear to be better placed 

 under Stipa than under Muehlenlergia. 



8. Obtzopsis, Mich. {TTrachne, Trin.), is a genus of about four- 

 and-twenty species, from the temperate and subtropical regions 

 of the northern hemisphere or from extratropical South America, 

 very rare within the tropics, most of them often regarded as 

 awned species of Milium, but really more nearly connected with 

 Stipa, from which they chiefly differ in the broader fruiting glume, 

 often oblique at the top, the awn usually short, slender, and 

 twisted, and very deciduous. The genus divides readily into 

 three sections, regarded by some as distinct genera, but all united 

 into one by Trinius and others. 1. Piptatlierum, Beauv., com- 

 prises the Old- World species, often included in Milium as a 

 section, with awned glumes, and really connecting in some mea- 

 sure the two genera. The obliquity of the fruiting glume is 

 much less marked than in the typical species of Oryzopsis ; and 

 the rhachilla of the spikelet is glabrous. 2. Euoryzopsis or 

 Oryzopsis proper, including the proposed genera CaryocMoa, 



