Myosotis macrosperma Engelm., big–seeded scorpiongrass, spring forget–me–not. Annual, slender–taprooted, not rosetted, 1—2–stemmed at base, with ascending branches, in range to 25 cm tall; shoots with only cauline leaves, hispid with hairs to 1 mm long having bulbous bases (pustulate), not hooked.
Stems 2–ridged, in range to 4.5 mm diameter, initially with 2 low ridges descending from each cauline leaf, green.
Leaves helically alternate, simple and sessile, without stipules; blade narrowly obovate to narrowly elliptic–oblong, in range 14—67 × 5—13 mm, tapered at base, entire, obtuse with a callus tip, midrib slightly sunken on upper surface and raised on lower surface.
Inflorescence cyme, terminal on main and lateral stems, 10+–flowered, not conspicuously 1—sided, buds and open flowers coiled at tip, flowers at anthesis stalked, lacking bracts, ± strigose with upward–pointing hairs; peduncle cylindric, < 10 mm long; rachis internodes at anthesis ± 1.5 mm long increasing to 35 mm long in fruit; pedicel 1—1.5 mm long increasing 2× and arching in fruit, initially densely hispid aging strigose with upward–pointing hairs.
Flower bisexual, radial, 2 mm across; calyx unequally 5–lobed, at anthesis with erect lobes becoming ascending to spreading; at anthesis 2—2.5 mm long increasing 3× in fruit, green, densely covered with colorless, stiff, hooked hairs (uncinate) ± 1 mm long, the hook curved toward the flower; tube cup–shaped, to midpoint and ± 1.2 mm wide; lobes acute–triangular, lower > 2 lateral > 2 upper lobes, each usually 3–veined; corolla 5–lobed, short–shaped, white, glabrous; tube + throat 2.4—2.7 mm long, > calyx, the widest at base around ovary 1.2 mm gradually tapered to 0.5—0.6 mm wide at orifice, with 2 small, scalelike appendages at base of each lobe; lobes equal, broadly ovate, ca. 0.5 × 0.5 mm; stamens 5, fused to corolla tube < 1 mm above base, anthers at same height, included; filaments 0.1—0.15 mm long, white; anthers dorsifixed, dithecal, ca. 2 mm long and orange–reddish + colorless tip to 0.15 mm long, longitudinally dehiscent; pollen orangish; nectary disc beneath ovary inconspicuous; pistil 1, included; ovary superior, deeply 4–lobed, ca. 0.35 mm long, lobes spheroid, green, glabrous, 4–chambered, each chamber with 1 ovule; style arising from center of ovary lobes, 0.6—0.7 × 0.2 mm not increasing in fruit, pale green, glabrous; stigma capitate, green.
Fruits nutlets, 2(—4) and opposite with 2 opposite aborted, erect, lens–shaped ovate, ± 2 × 1.7 × 0.75 mm, glossy brown (greenish brown) and smooth, narrowly rimmed, obtuse at tip, glabrous.
A. C. Gibson