Caryopsis ellipsoid-acute, with traces of the stigma. It falls easily. No distinct groove, section somewhat triangular. Rachilla truncate. [Illustration: Fig. 54. _Poa nemoralis. c_, the minute “seed” (to the right) and caryopsis (to the left) nat. size. _a_, the “seed,” × 8; _b_, the caryopsis, × 8. Traces of a basal “web,” not shown here, occasionally occur. Nobbe.] [Illustration: Fig. 55. _Poa pratensis._ Type of a “webbed seed.” _a_, “seed,” × about 7; _b_, caryopsis (inverted), × 7. Between are the same, nat. size. Note the nerves on the palea and the conspicuous “web” at the base _a_. Nobbe.] [Illustration: Fig. 56. _Poa trivialis. a_, “seed,” nat. size and × 8; _b_, caryopsis, nat. size and × 7. Note the conspicuous “web.” Nobbe. Cf. Fig. 43.] _Poa compressa_, L. Palea obtuse, nearly glabrous and nerveless, or faintly 3-5 nerved and with a faint web. It is close to _P. pratensis_. _Poa trivialis_, L. (Fig. 56). “Seed” 2-2·5 mm., and with a bluish or bronzed cast. Caryopsis 1-1·5 mm. Palea acute, distinctly five-ribbed, glabrous, the margin scarcely overlapping. Caryopsis grooved, blunt and more tightly held in the palea. _P. trivialis_ differs from _P. pratensis_ chiefly in the distinct ribs and smoother palea, grooved caryopsis, and bluer hue. _P. nemoralis_, L., hardly differs from _P. trivialis_, but the paleæ are sub-acute, nerves obsolete, and scarcely hyaline at the margins. The “seed” is shorter and more acute, and the colour less pronounced, and with hardly a trace of hairs (Fig. 54). When the basal hairs are absent this should go with _P. annua_, &c. (see p. 146). It is practically impossible to distinguish these species by the “seed.” Care is necessary to distinguish _Kœleria_, which is somewhat larger in size, keeled, compressed and nerved similarly, but is more pointed and curved and paler yellowish white in colour. Hard and devoid of web or hairs. _Aira_ is distinguished by the awn: _Agrostis_ by the very different paleæ and caryopsis. The other Poas are devoid of web, though they may have hairs below, and require very careful examination. The whole group is excessively difficult to deal with in “seed,” and a special study of it is needed, since several species are important, and it forms a type. _b_ No web or pencil of hairs below the “seed.” (1) _Apex of palea rounded, blunt, notched, or at most bluntly pointed, but with no trace of awn-or bristle-tip._ * Palea inflated, round-backed and somewhat winged, membranous. _Briza media._ _B. minor._ _Briza media_, L. Paleæ blunt, 2·5-3 mm., without lateral projections, markedly convex--almost conduplicate; nerves several. Caryopsis ovoid, 1·5-2·5 mm., dark brown. Sometimes called a good grass, but meagre and only found in poor meadows in this country.