GRASSES. Poaeem or Graminem. Figs. 515-565.
Annual or perennial herbs with characteristic narrow leaves and round or flattened, jointed, usually hollow stems. In the bamboos, the stems are woody and may reach the height of one hun dred feet or more. The stems or culms are solid at the nodes or joints and usually hollow between, but may be pithy, as in the Indian corn and other large species. The basal part of the leaf envelops the stem, forming the sheath. The blades are parallel- veined. The flowers are inconspicuous, solitary or several together in spikelets, and these spikelets variously arranged in spikes or panicles. The flowers have no proper perianth but are in cluded between scales in two ranks. A spikelet consists of a short axis bearing at the base two empty scales or glumes (empty glumes of some authors); above these are one or more flowers, each in the axis of a scale called the lemma (flowering or floral Blume of some authors); between the flower and the axis is a two-keeled scale, the palea.
The flower consists of a pistil and usually three stamens. The pistil consists of a one-celled ovary and two styles and feathery stigmas. The seed is usually grown fast to the pericarp, forming a grain, and it may also be closely united with the lemma and palea, as in the oat. The spikelet is one-flowered in Agrostis and Phleum, several-flow ered in Poa and Triticum. In some genera, such as Panicum, the lower lemma is empty or contains only stamens. The spikelet appears then to have three empty glumes. The inflorescence or flower cluster is a spike in wheat and a panicle in the oat, while in timothy (Phleum) the panicle is so con tracted as to appear as a spike. The glumes and lemmas may bear bristles or awns on the tip or back, as in barley. The staminate and pistillate flowers are in separate parts of the same plant (moncecious) in corn, and may even be in separate plants (dicecious), as in Buffalo grass and Texas blue-grass.
Plants often produce creeping stems below the surface of the ground, by which they spread and form a sod. These rootstocks resemble roots but are jointed like stems and bear scale-like leaves.
Familiar examples are Johnson -grass and blue grass. Perennial grasses which do not bear root stocks tend to grow in hunches or tussocks, and are known as bunch-grasses. Orchard-grass is of this kind.
This article is restricted to a botanical discussion d the sr:vises. In sonic cases reference is made to - • al arti6._s on the individual grasses for the c . t it .tes. For cultural notes on all others the . r hall consult Spillman's article on Mcadows 1. Zea (Latin name for spelt). A genus of grasses represented by a single American species known only in cultivation. Flowers monmcious, the staminate borne in large termi nal panicles (the tassel), and the pistillate borne in the axils of the leaves in several rows on a thickened axis (the cob), and en closed in several large foliaceous bracts, the whole constituting the ear. The greatly elongated styles project from the tip of the ear and form the silk.
Mays, Linn. Indian Corn. Maize. (Fig. 515.) A well-known, large, annual grass with broad leaves, extensively cultivated for forage and grain. The origin of the cultivated varieties of corn is uncertain but must be Ameri can, and was prob ably in the tableland of Mexico or Central America where it has been cultivated longest. It has been sug gested that it may have originated from Euchlcena Mexicana, which it much resembles in habit, but differs from in having the several pistillate spikes united in a compound inflorescence or ear. [See Maize.] 2. Euchlna (Greek, eu, well, and chlaina, mantle, alluding to the large glumes). A genus of grasses represented by a single Mexican species. Flowers mornecious, the staminate in panicled racemes terminating the stalks, the pistillate in jointed spikes fascicled in the leaf axils, each spike more or less enveloped in foliaceous bracts. Zea (Indian corn) differs from this chiefly in having pistillate flowers arranged in several rows on a single axis or "cob." The varieties are recognized by some authors as species.