132 ME. G. BENTHAM ON GRAMINE^. 



extreme readiness with which some species hybridize with the 

 cultivated wheats has given rise to the suggestion, strongly advo- 

 cated by some, positively rejected by others, that it is in some of 

 the common species oi j^gilops that we must look for the original 

 of our cereal wheats. 



The second subtribe, Lepturem, is characterized by the slender 

 spikes and the spikelets solitary at the notches, each with only 

 one or rarely two flowers. We refer to it five genera, placed by 

 Kunth and some others in Eottboelliese, from which they differ in 

 the outer empty glumes, when present, persisting below the arti- 

 culation of the rhachilla. 



5. LEPTTTErs, Br., including Fholiurus, Trin., has six species, 

 five of them with the ordinary geographical range of the tribe, 

 the sixth, L. repens, Br., exclusively Australasian or South Pacific 

 and maritime. They are distinguished in the subtribe by the 

 rigid outer empty glumes, one or two in number, much longer 

 than the hyaline flowering glume, thus showing the nearest 

 approach to Eottboelliese. They differ from each other sufficiently 

 to have been referred by different botanists to different genera. 

 L. cylindricus, Trin. (-£. subulatus, Kunth), included by Link in 

 Ophiurus, by Keichenbach in Monerma, has one outer empty glume 

 and one flower with no empty glume above it. The Australasian 

 L. repens, a much larger plant than any of the others, has one 

 outer empty glume, one flower, and above it a glume either 

 empty or enclosing a palea, but no flower. L. persica, L. incur- 

 vata, and L. filiformis, Trin., have two lower empty glumes, one 

 flower, and no empty glume above it. li. pannonicus, Kunth, 

 forming Trinius's genus PhoUurus, and referred by T. Nees to 

 Ophiurus, has two outer empty glumes and two perfect flowers. 



6. PsiLUEiTS, Trin. {Monerma, Beauv., partly, Asprella, Host 

 but not of Willd.), is a single annual, near Lepturus, but with 

 only one minute empty glume, a single narrow and awned flower- 

 ing glume, and only one stamen in the flower. 



7. Naedus, Linn., is a single well-known small perennial, the 

 position of which in the system is rather puzzling. The spikelet 

 has only one flower without any empty glumes below it or pro- 

 longation of the rhachilla above it, which might have decided its 

 relatiouship either to Panicacese or to PoacesB, and its long simple 

 style might indicate an afSnity to some Panicese or to Sesleriese ; 

 but on the whole it seems nearest allied to the Lepturese, a sup- 

 position which might be confirmed, if we regard the rather pro- 



