86 ME. a. BENTHAM ON GEAMINEiB. 



received the name of Sohnidtia. 18. Phippsia, Br., is a dwarf 

 paniculate slender Arctic grass, cMefly distinguishable from Spo- 

 rdbolus by the minute lower empty glumes. 



19. SpoKOBOLrs, Br. (Vilfa, Beauv., Agrosticula, Eaddi, Tria- 

 chyriwn, Hochst., Gryptostachys, Steud.), is now a genus of about 

 eighiy species, spread over the warmer and temperate regions of 

 both the New and the Old "World, mostly, however, American, with 

 a very few European or Asiatic. Included by the older authors 

 in Agrostis, it has since been universally acknowledged as dis- 

 tinct, though different characters have been assigned to it. 

 Beauvois, who attached primary imp ortance to the presence or 

 absence of the awn, referred to it all the unawned species of the 

 old genus Agrostis. Brown, who first pointed out the differences 

 in the fruit, took as the principal character the loose membra- 

 nous pericarp readily detachable from the seed ; but this, though 

 very conspicuous in S. indicus, Br., and in some other species, is 

 not apparent in the dried state in several others ; and in S. virgi- 

 cus, Kunth, and others, it is only when soaked that the pericarp 

 can be detached. On this account it has been attempted to 

 establish two genera, Vilfa and Spordbolws ; but the character is 

 far too indefinite, as well as uncertain, to be available even for 

 sectional separation. As a whole, Sporoholus is chiefly distin- 

 guished from Agrostis by the total absence of any dorsal awn, 

 and by the grain so loosely enclosed in the glume that it usually 

 protrudes from it when ripe, and often falls away. The palea 

 also generally splits readily into two, and in some species is 

 even at the time of flowering divided to the base, a character 

 which G-risebach, who only observed it in an Argentine species, 

 was induced to take as that of a new genus Diachyrium ; but it 

 exists in many other species ; and this divided palea has been 

 more than once described, and even figured (as in T. Nees's 

 ' Genera Moraa Germanicse '), as a two-valved pericarp, a character 

 unknown in Graminese. Brown's name Sporoholus was rejected 

 by Beauvois, Trinius, and others on the supposition that the genus 

 is identical with the older established Vilfa, Adans. That, how- 

 ever, is a mistake. Adanson's character of Vilfa is so vague 

 that it cannot be identifled by that alone ; but in his index he 

 fixes it by quoting two European species, which are certainly both 

 of them true species of Agrostis, 



Two North-American species of Sporoholus, S. compressus, 

 Trin., and S. serotinus, A. G-r., are exceptional, not only in the 



