Bromus giganteus, L.
Palea 7 mm. long and inrolled, the base and rachilla bristly, indistinctly 5-7 nerved, the tip bifid: sub-terminal awn serrulate, 12-15 mm. long.
Caryopsis 4·5 mm. long, flattened, thin, glabrous.
The caryopsis is shorter and more ovoid than in other Bromes.
≡ ≡ Palea expanded above (coracle-shaped), awn from sinus between two blunt or triangular teeth.
Bromus arvensis.
Bromus arvensis, var. mollis, L. (Fig. [73]).
Palea oblong or obovate, somewhat flattened above (coracle-shaped), distinctly 5-7 ribbed, 8-9 mm. long, not hairy, though the ribs may be ciliate. Awn smooth, arising from the depression between two teeth or rounded projections. Caryopsis flattened and thin, 6 × 1·5 mm.; apt to fall loose from the paleæ.
In the variety B. secalinus the awn is usually shorter than the elliptical palea, and originates in the sinus of a notch (Fig. [74]): in B. mollis from between two teeth, and is as long as the obovate palea.
Bromus maximus and B. madritensis are both rare.
The broader nerved paleæ of B. mollis and shorter, fatter caryopsis, as well as the longer awn distinguish it from B. secalinus and B. arvensis. In the other Bromes the palea is more inrolled and the “seed" more slender as a rule. The rachilla is usually bent above into a slight kink.
The Bromes are an extremely difficult group. The awn is inserted between the two teeth of the palea or just below. The palea smooth or ciliate on the nerves or roughly hairy. The fruit is flattened in the antero-posterior plane, and usually shines through the closely investing palea. A rachilla is visible. In Brachypodium the caryopsis is less flattened, and the apex tapers into the awn without teeth. In Lolium and Agropyrum the caryopsis is still more wheat-like and grooved.
| Fig. 73. Bromus arvensis, var. mollis. a, “seed," nat. size; b and c, the same, × 3. d, caryopsis, × about 3. The awn originates between two teeth of the strongly ribbed palea. Coracle-shaped type. Nobbe. | Fig. 74. Bromus arvensis, var. secalinus. a, spikelet, b and c, “seed," nat. size; d and e, the same, × 6. Nobbe. Cf. Fig. [73]. |
All our Bromes are weeds, but some of them are important adulterants, requiring careful examination.
B. inermis is cultivated, and is a valuable grass. Awn short or wanting. Paleæ strongly 5-7 ribbed, inner with a marked central rib, closely adhering to caryopsis.
B. Schraderi is also said to be valuable.
†† Caryopsis not thin and flattened, corn-like, 3·5-5 mm. Palea smooth, inflated, boat-like.
Lolium temulentum.
A weed of cultivation, said to be poisonous to cattle, a possible explanation of which may be found in a fungus recently discovered as a very constant inhabitant of the tissues under the seed coats.