Triticum.] GRAMINE^E. 315 



25. TRITICUM. Linn. Wheat or Wheat-grass. 



Calyx 2-valved, many-flowered ; its valves opposite, trans- 

 verse, the sides (not the back of one of them) directed to 

 the rachis, nearly equal. Corolla 2-valved, valves lanceolate ; 

 exterior one acuminate or avvned at the extremity, interior 

 bifid at the point. There are two natural groups in this 

 genus : first, the large annual species, exotic to our country, 

 which are cultivated so extensively as Bread-corn; and, 

 secondly, the smaller perennial species, several of which are 

 natives with us. These, some authors look upon as two dis- 

 tinct genera; Triticum and Agropyrum, ( Beauv., Lindl.J 

 We have only to consider the latter genus, or group. Name, 

 Triticum, " quod tritum est e spicis :" because it is thrashed 

 or beaten from the spikes. 



Triandria. Digynia. 



# Spikelets distichous. 



1 . T. caninum, Huds. Fibrous-rooted Wheat-grass. Calyx- 

 awn valved, with 3 5 ribs, and about five awned florets ; leaves 

 plane; root fibrous. Br. Fl. ed. 3. p. 56. E. Fl. v. i. p. 184. 

 E. Bot. t. 1327. Elymus can., Linn. 



Woods and hedges. Plentiful at Woodlands, County of Dublin. 

 Fl. July. 1. Best distinguished from the following by its fibrous 

 root. 



2. T. repens, Linn. Creeping Wheat-grass or Couch-grass. 

 Calyx-valves many-ribbed, with from 4 8-awned (rarely awn- 

 less) florets; leaves plane ; root creeping. Br. Fl. ed. 3. p. 56. 

 E. FL v. i. p. 182. E. Bot. t. 909. 



Fields and waste places, abundant. Fl. throughout the summer 

 months. 1. In habit between the preceding and the following, 

 having a glaucous tint when growing near the sea. Leaves plane, or 

 nearly so. Spikelets smaller and less compressed than in T.junceum. 

 This pest of the corn-fields is difficult to be extirpated, on account 

 of its long creeping roots. 



3. T. Junceum, Linn. Rushy Sea Wheat-grass. Valves of 

 the calyx obtuse, much ribbed, with 4 5 awnless florets ; leaves 

 involute, pungent ; root creeping. Br Fl. ed. 3. p. 56. E. 

 Bot. t. 814. E. Fl. v. i. p. 182. 



Sandy sea-shores, frequent. FL July. 1 . Whole plant glaucous, 

 rigid. One and a half to three feet high. Spike long 1 . Spikelets ob- 

 long, much compressed, distant, sessile. Calyx-valves oblongo-lan- 

 ceolate, often with three teeth at the point. Exterior valves of the 

 corolla similar, with five nerves. 



H * SpiJtelets secund. 



4. T. loliaceum, Sm. Dwarf Sea Wfaat- grass. Valves of 



