Anthoxanthum odoratum, L. (Fig. [67]).
The one-flowered spikelet has four hairy glumes, the outer pair of which are unequal and awnless: the “seed" consists of the inner pair of golden-brown hairy and dorsally awned glumes, covering the thin, membranous, shining, smooth, blunt paleæ and the caryopsis, to which the inner palea adheres. Total length, without awns, about 3-4 mm. Palea 1·6 mm. Caryopsis 1·5 mm., brown, shiny, and easily separating. One awn is short, stiff and straight and inserted above the middle of its glume; the other longer and sharply bent, inserted about the middle.
Hierochloe, a rare northern grass, also comes here.
ΔΔ Glumes connate below, hairy on the keels.
Alopecurus pratensis.
A. geniculatus.
A. agrestis.Alopecurus is very characteristic, and should be carefully examined as a type. A. pratensis is a valuable grass and said to be often adulterated with the undesirable A. agrestis, Holcus, &c. Arrhenatherum and Avena are easily distinguished by the basal hairs, rachilla, &c.
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Alopecurus pratensis. A. geniculatus. A. agrestis. |
Fig. 68. Alopecurus pratensis. a, “seed," nat. size, and b, c, ditto, × 8; d, caryopsis, × 7. The “seed" here consists of the two glumes, connate below and hairy on the keel and ribs, including the caryopsis enveloped in a single palea with a dorsal awn. Note remains of stigma in d. Nobbe.
Alopecurus pratensis, L. (Fig. [68]).
Inner palea absent. Outer palea 5 mm., caryopsis 3 mm. long, often with remains of the stigma.
The greyish-brown spikelet of Alopecurus easily falls as a whole, included in the glumes; the palea is loose and delicate.