Rachilla hairy. Whole “seed" browner than Avena flavescens (see p. [158]).
Fig. 70. Aira flexuosa. a, “seed," nat. size; c and d, the same, × about 7; b, portion of fruiting panicle, showing the flexuous rachis; e, the caryopsis, nat. size; f, ditto, × about 7. Note the basal hairs and twisted awn. Nobbe. Cf. Fig. [44].
An almost worthless grass, on sandy soils, but important as an impurity in Avena flavescens (see note, p. [158]).
Aira cæspitosa, L. (Fig. [44]).
The palea, about 2·5 mm. long, toothed above, has a fine straight hair-like basal awn not longer than itself. Caryopsis 1·3 mm., grooved. Rachilla distinctly hairy.
Easily distinguished when mixed with Poa nemoralis, &c.—e.g. by the awn, hairs on rachilla, &c. It requires scrutiny in regard to Agrostis, which also has no awn or basal hairs.
✲✲ No basal tuft, or merely a few short microscopic hairs below. Paleæ not bifid above.
Agrostis canina.
A. Spica-venti.
A. setacea.
| Agrostis canina. A. Spica-venti. A. setacea. |