MR. G. BENTHAM ON GRAMINE. 131 
and close together in a short dense spike, the narrow empty 
glumes nearly equal-sided and keeled. Two species, 4. villosum 
(Secale villosum, Linn., Haynaldia, Schur) and A. hordeaceum, 
Boiss., form the proposed section Dasypyrum, Coss. and Dur. 
(Pseudosecale, Gren. and Godr.), differing slightly from the other 
species in the empty glumes rather unequal-sided, and one lateral 
nerve on one side of the keel very frequently as prominent as the 
keel itself, giving the glume the appearance of being two-keeled. 
Heteranthelium, Hochst., from the Levant, is a species very near 
A. (.Eremopyrum) orientale, with a dense villous spike, and several 
of the spikelets, especially near the base and apex of the spike, 
often sterile with empty glumes. ` 
3. Secare, Linn., is now reduced to two species or perhaps 
varieties, the cultivated Rye, of which S. montanum, Guss., is 
supposed to be the original spontaneous form, and S. fragile, 
Bieb. The genus differs slightly from the section Eremopyrum 
of Agropyrum in the dense cylindrical spike, and in the spikelets 
usually containing only two flowers. 
4. Trrricum, Linn., excluding Agropyrum and including Ægi- 
lops, can scarcely reckon more than ten botanical species; the 
most prominent character separating them from Agropyrum con- 
sists in the shape of the spikelets not so flat, and especially in the 
lateral nerves of the flowering glumes not connivent, but remain- 
ing parallel or nearly so, and either stopping short of the apex or 
produced beyond it into distinct teeth or awns. There are three 
rather distinct groups:—I. The cultivated Wheats, of unknown 
origin, in which the flowering glumes are keeled at the end and 
sometimes from the base, and terminate in a single awn, the 
lateral nerves usually barely reaching to the end of the glume. 
2. Crithodium, Link, founded on T. monococcum, Linn. (T. beoti- 
cum, Boiss.), in which the spikelets have only one fertile flower, 
and the flowering glume is keeled from the base and ends in 
a single awn. T. bicorne, Forsk., with two or even three fertile 
flowers and the lateral nerves of the flowering glumes sometimes 
produeed into short teeth, may be referred to the same section. 
3. Aigilops, Linn., above forty published species, which Munro 
reduces to seven or eight, differing from the cereal wheats in the 
flowering glumes more rounded at the back and not at all keeled, 
and in the lateral nerves of the flowering glumes often produced 
into long awns, especially in the upper end of the spike. The 
