Briza minor L., little quaking grass, lesser quaking grass. Annual, fibrous–rooted, 1—several–stemmed at base, cespitose, ascending, 15—50 cm tall; shoots with 4—7 leaves, stems commonly bending upward slightly at nodes.
Stems (culms) cylindric, slender, < 1 mm diameter, faintly striped green and white, internodes short at base and to 50 mm long above, glabrous at base, minutely scabrous approaching nodes and inflorescence; internodes hollow.
Leaves alternate distichous, simple with sheath; sheath open, > internode (lower shoot) to << internode (upper shoot), membranous on non–overlapping portions of margins, oblique at junction with blade, without lobes (auricles) at top; ligule membranous, acute to acuminate, 1—3.5+ mm long but also decurrent as a narrow membrane adjacent to sheath margin, often splitting lengthwise; blade lanceolate–linear to linear, 25—110 × 2—4.5 mm long, the widest below midpoint, flat, yellowish green, oblique at base with 1 margin ± wavy and incurved to margin of leaf sheath, the other margin straight and continuous with margin of leaf sheath, minutely toothed on margins base–to–tip, parallel–veined with midrib raised slightly on lower surface.
Inflorescence spikelets, in terminal, open, loose panicles, panicle dichotomously or trichotomously forked with 2—4 orders of branching and spreading axes, spikelets nodding, typically with 4—6(—7) fertile florets, bracteate, glabrous, lacking awns; principal axes slender and wiry, 5—25 mm long, generally decreasing with each order of branching, finely scabrous with upward–pointing teeth, with axillary pulvinus for each segment, stalk of spikelet 4.5—12 × < 0.1 mm, swollen beneath spikelet and green or becoming purplish.
Spikelet deltoid compressed side–to–side, in range 3—4.5 × 4 mm, florets conspicuously alternate distichous and decreasing in length base–to–tip, widely spreading, overlapping at bases, breaking above glumes and between florets; glumes 2, subequal, boat–shaped, in range 1.8—2.4 × 0.8—1.1 mm, lower glume slightly < upper glume, green, 3(—5)–veined, membranous on margins, sometimes with purple band between green and outer colorless margin, ± lobed (auriculate) at base; lemma < glume, domed clamshell–shaped, ca. 2 mm across (narrower and shorter in terminal florets), domed part hard, glossy light to pale green, with collapsed, blisterlike hairs (scurfy), venation obscure, membranous margin 0.6—1 mm wide, inrolled approaching tip, spreading laterally sometimes with purple band between green and outer colorless margin; palea tightly sealing flower against lemma, scarious, obovate, 1.3—1.6 × 0.8—1 mm to smaller in upper florets, 2–veined, 2–keeled with margin folded inward along veins and flat, with collapsed, blisterlike hairs on outer surface, veins fine and green.
Flower bisexual, some flowers with style exserted; perianth (lodicules) 2, narrowly ovoid to lanceoloid, 0.4 mm long, translucent; stamens 3, free, included; filaments threadlike, ± 1 mm long, translucent–white; anthers basifixed, dithecal, 0.25—0.5 mm long, whitish to light yellow, longitudinally dehiscent; pollen translucent–white; pistil 1; ovary superior, compressed–obovoid, ca. 0.4 mm long, colorless, 1–chambered with 1 ovule; styles 2, included, erect, feathery (narrowly plumose), 1—2.1 mm long.
Fruit achene (caryopsis), hemi–obovoid compressed front–to–back, 0.8—1 mm long, pale brown, with 1 face flat and other face convex, glabrous.
A. C. Gibson & B. A. Prigge