Festuca bromoides L., brome fescue. Annual, fibrous–rooted, 1—several(—many)–stemmed, often cespitose, erect to decumbent), 5—40(—50) cm tall; shoots with cauline leaves, glabrous to puberulent. Stems (culms): cylindric, slender, < 1 mm diameter, smooth, glabrous.
Leaves alternate distichous, simple with sheath; sheath open, 6—50 mm long, prominently veined, glabrous to puberulent, generally without lobes (auricles) at top; ligule membranous, truncate, 0.2—0.4 mm long, splitting in age; blade linear, in range 18—62 × 0.5—2.5 mm, flat or inrolled, minutely scabrous on margins, parallel–veined, glabrous or puberulent.
Inflorescence spikelets, in terminal, contracted raceme or panicles 15—70(—150) mm long, of alternate distichous, appressed to ascending lateral branches and short–stalked spikelet with 3—6 bisexual florets, lateral branches at base of array having 2+ spikelets, upper portion of raceme consisting of spikelets, awned; spikelet stalk 1.3—2 mm long; rachis triangular in ×–section and narrowly 3–winged, minutely scabrous along winged edges, with internodes 3—20 mm long and generally < spikelets, lacking pulvinus in axil with lateral branch or spikelet stalk.
Spikelet ± compressed–ellipsoid to compressed–lanceoloid, in range 5.5—8.5 mm long (excluding awn), terminal floret commonly sterile, breaking above glumes and between florets; rachilla internodes 0.8—1.2 mm long; glumes 2, unequal, lower glume narrowly lanceolate, in range 3.3—4 mm long and 1–veined, upper glume lanceolate, 4.5—6 mm long and 3–veined, sometimes with a short awn to 1 mm long, glumes membranous on margins and glabrous; lemma awned, narrowly lanceolate, in range 4—6 mm long, scabrous at least on midvein and margins above midpoint, glabrous, obscurely 5–veined, with a rounded, yellowish callus at base, the awn terminal, straight, in range 2.5—6 mm long, light–colored, scabrous; palea membranous and flat with infolded margins, = to lemma length, 2–keeled along 2 green veins, minutely scabrous along keels.
Flower bisexual; perianth (lodicules) 2, 0.6—0.8 mm long, unequally 2–toothed with erect teeth, translucent; stamens 1, free, included; filament threadlike, ca. 0.8 mm long, whitish–translucent; anther dithecal, ca. 0.4 mm long, purplish red, longitudinally dehiscent; pollen whitish; pistil 1; ovary superior, compressed–oblanceoloid to compressed–obovate, ca. 0.6 mm long, glabrous, 1–chambered with 1 ovule; styles 2 essentially separate (branched from near base), included, ± 0.75 mm long, white. Fruit: achene (caryopsis), dispersed tightly enclosed in awned floret with persistent rachilla segment; achene narrowly lanceoloid, 3.5—5 mm long, with groove on palea side, glabrous.
A. C. Gibson & B. A. Prigge