Fig 21. [June Grass. Kentucky Blue Grass. Poa pratensis] L.

June Grass. Kentucky Blue Grass. Poa pratensis L. Florets ovate-lanceolate, acute 3–4 mm. long, with three equal sides when seen in transverse section, nearly smooth, if severely rubbed in threshing, otherwise the floral glume is thickly webbed at the base; palea acuminate, grain light brown, elliptical, both ends usually pointed 1.2–1.4 mm. long, in cross sections with three equal sides, one of which has a shallow vertical groove. Compare with Poa compressa. Introduced from Europe.

Fig 22. [Rye. Secale cereale] L.

Rye. Secale cereale L. Grain light brown, 6–8 mm. long, elliptical, base acute, apex obtuse and rounded, in cross section the back somewhat acutely rounded, the opposite side with a narrow vertical groove, surface more or less irregularly wrinkled. Introduced from Europe. A bad weed in wheat fields.

Fig 23. [Pigeon-Grass. Yellow Foxtail. Setaria glauca] (L.) Beauv. Chaetochloa glauca (L.) Scrib.

Pigeon-Grass. Yellow Foxtail. Setaria glauca (L.) Beauv. Chaetochloa glauca (L.) Scrib. Spikelets light to dark brown, 2.5–3 mm. long; after threshing or much rubbing consisting of each a grain and two firm coverings, known as a floral glume which covers the sides of the somewhat depressed palea, oval, apex slightly 3-toothed, rounded side strongly arched, somewhat V-shaped, roughened crosswise by prominent fine more or less branching ridges; ridges of palea on concave side less prominent. Introduced from Europe. Very common in hoed annual crops.