1. Phleum pratense L. (Timothy)

Pl. 135 i–m; Map 549

P. pratense var. nodosum (L.) Hudson

P. pratense f. viviperum (Gray) Louis‑Marie

Plants perennial, sometimes relatively short‑lived, forming tufts. Flowering stems 50–100(–140) cm long, erect, sometimes from spreading bases, usually swollen and somewhat bulblike at the base, glabrous or roughened toward the tip. Leaf sheaths rounded on the back, glabrous, the ligule 1–5 mm long. Leaf blades 3–30 cm long, 3–8 mm wide, flat, glabrous or roughened along the margins. Inflorescences 3–15 cm long, appearing as dense, cylindrical spikes, the short branches fused to the main axis. Spikelets 1.8–3.2 mm long (excluding the awns), strongly flattened laterally, disarticulating above the glumes, the glumes also sometimes shed with age, with 1 perfect floret and without additional staminate or sterile florets. Glumes with the body 1.8–3.2 mm long, longer than the lemma, similar in size and shape, oblong, abruptly rounded or narrowed at the tip to an awn 0.5–1.5 mm long, strongly keeled and 3‑nerved, thin and membranous along the margins, hairy on the nerves. Lemma 1.3–2.4 mm long, thin and membranous, oblong‑elliptic, rounded to abruptly pointed at the tip, awnless, 5‑nerved, glabrous. Palea similar in appearance to the lemma but slightly shorter. Stamens 3, the anthers 1.2–1.8 mm long. Fruits 1.0–1.4 mm long, oblong‑elliptic in outline, yellowish brown. 2n=14, 21, 28–84. May–August.

Introduced, scattered to common nearly throughout the state (native of Europe, widely naturalized in the U.S. and Canada). Upland prairies, margins of ponds, and banks of streams; also pastures, crop fields, old fields, ditches, roadsides, railroads, and open, disturbed areas.

The common name, “Timothy,” originated with the introduction of this species to the United States from Europe in about 1720 by Timothy Hanson of Maryland (Steyermark, 1963). It is planted widely in pastures and is an important hay and forage species nationally, but it is also one of the worst causes of hay fever in the late spring and early summer. Phleum pratense bears a strong superficial resemblance to Alopecurus pratensis, with which it might be confused if specimens are not examined closely.