130 MR. G. BENTHAM ON GRAMINEE. 
Old World, chiefiy in the northern hemisphere ; and scarcely any 
species, except as introduced weeds or eseapes from cultivation, 
penetrate within the tropics. The twelve genera are readily 
ranged in three distinet subtribes, and require but little comment 
on the present occasion. 
The first subtribe, Triticeæ, comprises four genera, in which 
the spikelets have three or more, or very rarely only one or two, 
flowers, and are singly sessile at each notch of the rhachis. 
1. Loriuw, Linn., is at once distinguished from all others of 
the tribe by the position of the flat spikelets with their edge 
to the rhachis. Steudel enumerates twenty-two species; most 
authors reduce them to three or four, which run much into each 
other. De Rouville published at Montpellier a detailed mono- 
graph, in which he rejects all the old species and redivides the 
genus into three primary and several subordinate races, to which 
he gives new characters and new names, doing little but add to 
the prevailing confusion. "Two genera have been founded on in- 
dividual species or forms—C'epalium, Schrank, is the L. temulen- 
tum, Linn., and Arthrochortus, Lowe, is a Madeiran species or 
variety very near to L. rigidum, Gaudin (L. strictum, Parlat.), 
and to some varieties of L. temulentum. u 
2. AGROPYRUM, J. Gertn. ( Elytrigium, Desv.), contains about 
twenty species, formerly regarded as congeners of the cultivated 
Wheats, from which they differ much in habit and technically in 
the lateral nerves of the flowering glumes connivent at the top 
or confluent into the terminal awn. They are well distributed 
into two sections :—1. Agropyrum proper, mostly perennials, 
with the spikelets more or less distant along the common pe- 
duncle or rhachis, the outer empty glumes usually very unequal- 
sided and not keeled. To this section belong the common A. re- 
pens, A. junceum, A. caninum, and a few others. Ragneria, 
C. Koch, is, according to Grisebach, a species closely allied to 
A.caninum. | Anthosachne, Steud., is the Australasian A. scabrum, 
Beauv. (Festuca scabra, Labill.), which, with the closely allied 
East-Indian A. semicostatum, Nees, and the Oriental A. longearis- 
tatum, Boiss., differs from the commoner species in the denser 
spikes and narrower glumes tapering into long awns at length 
diverging. A. pectinatum, Beauv., is an Australian species still 
further connecting Agropyrum proper with Zremopyrum. 2. Ere- 
mopyrum, Ledeb. (Cremopyrum, Schur, perhaps by a clerical 
error, Costia, Willk.), mostly annuals, with the spikelets distichous 
