Agropyrum repens, Beauv. (Fig. [76]).
Palea tough, 10-12 mm. long, ovate-lanceolate, 3-5 ribbed and smooth; with a short (2-3 mm.) or long (8 mm.) terminal awn or a mere tooth. Rounded back. Fruit grey-brown, ciliate above, 5-6 × 1·4 × 0·7-0·9 mm., depressed, hardly grooved, adhering to the palea. Rachilla smooth or not, and narrowed below.
A noxious weed (see p. [150]) and hence should be carefully excluded from “seeds."
A. caninum, Beauv., has a longer (10 mm. or more) and rougher awn, and is smaller (about 8 mm.), but otherwise very similar. Palea smooth except at the five-nerved apex. Rachilla thickened above, and hairy (Fig. [75]).
Elymus differs from Agropyrum in its harder velvety palea, no awn, and its club-like velvety rachilla. It is also larger altogether, as a rule.
Fig. 77. Brachypodium pinnatum. Type of boat-shaped “seed" with awn. a, nat. size; b and c, × 7. Nobbe. Cf. Fig. [72].
++++ Palea seven-ribbed, smooth.
Brachypodium pinnatum.