The spikelets form a loose panicle,)(Ix.
The small flowers or spikelets are borne in pairs on the ultimate branches of a much branched feathery plume-like terminal grey inflorescence, 2 ft.
All the flowers of each triplet of spikelets on both sides of the rachis are fertile and produce ripe fruits; hence the ear produces six longitudinal rows of grain.
The central fruits of each triplet form two regular rows, but the lateral spikelets form not four straight single rows as in (ii.), but two regular double rows, the whole ear appearing irregularly four-rowed.
The spikelets are borne on a compound or branched spike, erect at first but afterwards bent downwards.
The minute flowers are arranged in spikelets somewhat as in grasses, and these again in larger spike-like or panicled inflorescences.
The spikelets are usually many-flowered and variously arranged in racemes or panicles.
These are arranged so as to form spikelets (locustae), and each spikelet may contain one, as in Agrostis (fig.
The flowers are, as a rule, placed laterally on the axis(rachilla)of the spikelet, but in one-flowered spikelets they appear to be terminal, and are probably really so in Anthoxanthum (fig.
9), Coleanthus, Nardus) the spikelet consists of nothing more, but usually (even in uniflorous spikelets) other glumes are present.
But it is usual to find, besides the basal glumes, a few other empty ones, and these are in twoor more-flowered spikelets (see Triticum, fig.
Involucres or organs outside the spikelets also occur, and are formed in various ways.
Any number of spikelets may compose the inflorescence, and their arrangement is very various.
In the spicate forms, with sessile spikelets on the main axis, the latter is often dilated and flattened (Paspalum), or is more or less thickened and hollowed out (Stenotaphrum, Rottboellia, Tripsacum), when the spikelets are sunk and buried within the cavities.
Every variety of racemose and paniculate inflorescence obtains, and the number of spikelets composing those of the large kinds is often immense.
Rarely the inflorescence consists of very few flowers; thus Lygeum Spartum, the most anomalous of European grasses, has but two or three large uniflorous spikelets, which are fused together at the base, and have no basal glumes, but are enveloped in a large, hooded, spathe-like bract.
18, and Paniceae), and in these the male flower of a spikelet always blooms later than the hermaphrodite, so that its pollen can only effect cross-fertilization upon other spikelets in the same or another plant.
In many-flowered spikelets the rachilla is often jointed and breaks into as many pieces as there are fruits, each piece bearing a glume and pale.
One-flowered spikelets may fall as a whole (as in the tribes Paniceae and Andrepogoneae), or the axis is jointed above the barren glumes so that only the flowering glume and pale fall with the fruit.
In the sugar-cane (Saccharum) and several allied genera the separating joints of the axis bear long hairs below the spikelets; in others, as in Arundo (a reed-grass), the flowering glumes are enveloped in long hairs.
Spikelets one-flowered, rarely two-flowered as in Zea, falling from the pedicel entire or with certain joints of the rachis at maturity.
Hilum a point; spikelets not laterally compressed.
Spikelets unisexual, male and female in separate inflorescences or on different parts of the same inflorescence.
Spikelets bisexual, or male and bisexual, each male standing close to a bisexual.
Spikelets falling singly from the unjointed rachis of the spike or the ultimate branches of the panicle.
Hilum a line; spikelets laterally compressed.
Spikelets oneto indefinite-flowered; in the one-flowered the rachilla frequently produced beyond the flower; rachilla generally jointed above the empty glumes, which remain after the fruiting glumes have fallen.
A Spikelets upon distinct pedicels and arranged in panicles or racemes.
Spikelets more than one-flowered.
(3 Spikelets crowded in two close rows, forming a one-sided spike or raceme with a continuous (not jointed) rachis.
Y Spikelets in two opposite rows forming an equal-sided spike.
The spikelets are arranged in spike-like racemes, generally in pairs consisting of a sessile and stalked spikelet at each joint of the rachis (fig.
Elionurus, a widespread savanna grass in tropical and subtropical America, and also in the tropics of the old world, is rejected by cattle probably on account of its aromatic character, the spikelets having a strong balsam-like smell.
Other aromatic members are Andropogon Nardus, a native of India, but also cultivated, the rhizome, leaves and especially the spikelets of which contain a volatile oil, which on distillation yields the citronella oil of commerce.
- A pair of a variety is used by the negroes in western spikelets of Andro- Africa for haemorrhage.
Amphicarpum, native in the southeastern United States, has fertile cleistogamous spikelets on filiform runners at the base of the culm, those on the terminal panicle are sterile.
The spikelets are sometimes unisexual, and there are often six stamens.
Pratense (Avena flavescens) with a loose panicle and yellow shining spikelets is a valuable foddergrass.