The cultivated varieties are extremely numerous, some kinds being adapted for marshy land, others for growth on the hill A, spikelet (enlarged) B, bearded variety sides.
Short spikes may fall from the culm as a whole; or the axis of a spike or raceme is jointed so that one spikelet falls with each joint as in many Andropogoneae and Hordeae.
The axis of the spikelet is frequently jointed and breaks up into articulations above each flower.
In Cynosurus (Dog's tail) -- C the pectinate involucre which conceals the spikelet is a barren or abortive spikelet.
Various methods of scattering the: grain have been adopted, in which parts of the spikelet or inflorescence are concerned.
Each spikelet contains a solitary flower with two outer small barren glumes, above which is a large tough, compressed, often awned, flowering glume, which partly encloses the somewhat similar pale.
Munro supplemented this by another character easier of verification, and of even greater constancy, in the articulation of the pedicel in the Paniceae immediately below the glumes; whilst in Poaceae this does not occur, but the axis of the spikelet frequently articulates above the pair of empty basal glumes.
Of these the two placed distichously opposite each other at the base of the spikelet never bear any flower in thei axils, and are called the empty or barren glumes (figs.
The pale is now generally considered to represent the single bracteole, characteristic of Monocotyledons, the binerved structure being the result of the pressure of the axis of the spikelet during the development of the pale, as in Iris and others.
In Setaria and allied genera the spikelet is subtended by an involucre of bristles or spines which represent sterile branches of the inflorescence.