THE FLOWERING. In the panicles the flowers open in basipetal order; the flowers in the spikes situated somewhat above the middle, commence to open first, and the flowering proceeds upwards and downwards. A few Grass-flowers never open (cleistogamic); _Leersia oryzoides_, _Stipa_-species, and _e.g._ Wheat and Rye in cold damp weather; some open their pales so wide that the anthers and stigmas may protrude at the top; most frequently the lodicules expand and force the pales suddenly and widely apart. The filaments elongate considerably, so that the anthers are pendulous and the stigmas unfold. In some Grasses _e.g._ Wheat, the blooming of each flower only lasts a short time. POLLINATION is generally effected by the wind. The _Rye_ separates the pales very widely in the morning, and allows the anthers and stigmas to appear; it is almost entirely sterile when self-pollinated. The _Wheat_ flowers at any time of the day, each flower lasting only a quarter of an hour. The pales open suddenly, but only half way, and the anthers scatter one-third of the pollen in their own flower and two-thirds outside. Self-pollination is effectual, but crossing gives better results. In _Hordeum vulgare_ (all flowers ☿) the flowers of the 4 outer rows behave as in the Wheat, but those in the two central rows always remain closed. The ☿-flowers in the two central rows of _H. distichum_ remain closed and fertilise themselves; they open exceptionally, and may be pollinated by the ♂-flowers in the 4 lateral rows. _H. hexastichum_ is cleistogamic. _Oats_ pollinate themselves. [Illustration: FIG. 292.--Barley grain: _A_ section through the skin (_a-d_) and the most external part of the endosperm; _Gl_ the “aleurone layer”; _st_ starch-containing cells; _B_ starch grains.] [Illustration: FIG. 293.--Wheat-grain germinating: _g_ the plumule; _b_ the first leaf succeeding the cotyledon; _r^1_ the primary root; _r^2_ lateral root.] [Illustration: FIG. 294.--Older seedling of the Wheat: _s_ the second sheathing-leaf; _l_ first foliage-leaf.]