1. Triticum aestivum L. ssp. aestivum (wheat)

Pl. 188 c–e; Map 762

Plants annual, forming tufts. Flowering stems 50–120 cm long, erect or ascending, glabrous. Leaf sheaths glabrous or the lowermost hairy, the ligule membranous, sometimes with an uneven margin. Leaf blades 3–40 cm long, 2–10(–20) mm wide, flat, glabrous or rarely roughened to hairy, often with auricles at the base. Inflorescences 5–12 cm long (excluding the awns), linear‑oblong in outline, somewhat flattened, with numerous, densely spaced, ascending spikelets crowded along the persistent axis. Spikelets single at the nodes of the inflorescence, all similar in size and appearance, narrowly elliptic in outline (excluding the awns), with 2–5 florets, disarticulating above the glumes and between the florets. Glumes similar in size and shape, the body 6–10 mm long, 3.0–6.5 mm wide, broadly ovate, the tip with 2 broad, triangular teeth, unevenly and often faintly 3–7‑nerved and with an off‑center keel, this reaching 1 of the teeth and often extended into an erect or ascending, roughened awn 2–60 mm long, glabrous, thickened and somewhat hard. Lemmas with the body 7–12 mm long, broadly ovate, the tip with 2 triangular teeth, unevenly and often faintly 5‑ or 7‑nerved and rounded or with an off‑center keel, this reaching 1 of the teeth and often extended into an erect or ascending, roughened awn 2–80(–150) mm long, glabrous, lacking stiff, spinelike hairs along the keel and margins, thickened and somewhat hard, with thinner margins. Anthers 2.5–4.0 mm long. Fruits 6–8 mm long, oblong‑ovate, grooved, usually hairy at the tip, yellowish brown. 2n=42. May–July.

Introduced, scattered sporadically nearly throughout the state (cultivated nearly worldwide, mostly in temperate regions, escaped sporadically in the eastern U.S.). Fallow fields, roadsides, railroads, and open, disturbed areas.

Wheat is one of the most important crop plants in the world. It is thought to have been developed through hybridization and selection from species native to the Middle East. In addition to its importance as a grain plant, dried plants sometimes are a source of pulp for making paper. In Missouri, it is cultivated for its grain and as an early spring source of forage and hay (winter wheat). Occasionally, it is seeded along road banks following construction as an annual cover crop to prevent soil erosion until other perennial plantings become established. Steyermark (1963) noted that the pollen is a cause of hay fever. Plants in the flora are escapes from cultivation and do not persist for long in nature. They all belong to the hexaploid ssp. aestivum, which includes the bread (cereal) wheats. Within this, a number of races exist, differing in whether awns are produced and in other, minor characters of the spikelets. Several additional subspecies are cultivated elsewhere for other purposes and also differ in minor details of spikelet morphology. Another taxon, T. turgidum L. ssp. durum (Desf.) Husn., which includes the tetraploid (2n=28) durum or macaroni wheats, also is cultivated in parts of the United States but has not been documented to escape in Missouri. It differs from T. aestivum in its denser inflorescences with more strongly overlapping spikelets and more strongly keeled, less inflated glumes.