A valuable and easily recognised grass. _Molinia_, _Holcus_ and similar impurities are easily detected: some Fescues are much more like it; e.g. _F. tenuifolia_ (see p. 46) in which the apex tapers suddenly to a point. _Dactylis_ should also be compared. †† Paleæ compressed or distinctly keeled. _Molinia cærulea._ _Kœleria cristata._ Unimportant, except as impurities among other grass “seeds.” _Molinia_ is said to occur as such in samples of _Cynosurus_, _Dactylis, Poa trivialis_, Fescues, &c., but it should give little difficulty except in comparison with _Glyceria_ (see p. 146). _Molinia cærulea_ (Mœnch.) (Fig. 61). “Seed” 3-4 mm. or more, leather coloured or with a bluish tinge. Paleæ divaricating, the lower keeled and compressed, and tapering to a sharp point. Rachilla long, oblique and prominent. Smooth tapering, palea 5·5, fruit 2 mm. long. _Kœleria cristata_, Pers. (Fig. 62). Palea 6 mm., keeled, entire, no awn but stiffly tapering, ribbed, no hairs. Rachilla large. Fruit 4·5 mm. [Illustration: Fig. 61. _Molinia cærulea. a_, “seed,” nat. size; _b_ and _c_, ditto, × about 8; _d_, the caryopsis, nat. size; _e_, ditto, × about 7. Note the compressed, keeled and glabrous palea, and the long slender bone-shaped rachilla. Nobbe.] [Illustration: Fig. 62. _Kœleria cristata. a_, the “seed” (to the left) and caryopsis (to the right), nat. size; _b_, “seed,” × about 7. The palea is compressed and keeled, and, like the large rachilla, glabrous. Nobbe.] ** Palea not taper pointed, but mucronate, or two-toothed, with a sub-terminal point or spine. _Elymus arenarius._ _Agropyrum repens._ _Dactylis glomerata._ _Sesleria cærulea._ _Elymus arenarius_, L. (Fig. 63). Fruiting palea lanceolate, 13-15 × 3 mm., tough and stiffly hairy or velvety: 5-7 ribs. Rachilla stout, hairy. Fruit hairy above, 5-11 mm. × 2·5 × 1·2, somewhat grooved. No keel. Apex of inner palea bifid, outer mucronate. Fruit shelled. Easily distinguished from _Digraphis arundinacea_, which has a basal hair-tuft and very different caryopsis; less easily from _Agropyrum_ and _Lolium_, except in the velvety surface. [Illustration: Fig. 63. _Elymus arenarius. a_, “seed,” nat. size; _b_ and _c_, the same, × 3. Note the stiff, velvety, bifid and mucronate outer palea, and the large hairy rachilla. Nobbe.] [Illustration: Fig. 64. _Dactylis glomerata. a_, spikelet with glumes removed, nat. size; _b_, ditto, × about 6; _c_ and _d_, “seed,” nat. size (below) and × about 6. The stiff and slightly curved awn-point is sub-terminal and arises from between two teeth. Rachilla dilated above. Nobbe. Cf. Fig. 60.] _Agropyrum repens_ may have a mucronate awn-point or not. The small palea 10-12, the caryopsis 5-6 mm. (see p. 169 for description).