1. Myosotis macrosperma Engelm. (big-seeded scorpiongrass)
M. virginica var. macrosperma (Engelm.)
M. verna var. macrosperma (Engelm.) Chapm.
Map 1303, Pl.
with slender taproots. Stems 20–60 cm long, erect or ascending, not
rooting at the lower nodes, solitary or occasionally few, usually unbranched
below the inflorescence, moderately to densely pubescent with fine, loosely
ascending to spreading, usually minutely pustular-based hairs, these not hooked
at the tip. Leaf blades 2–8 cm long, 6–16 mm wide, lanceolate
to narrowly oblong-elliptic or oblanceolate, rounded or angled to a bluntly or
sharply pointed tip, the surfaces and margins densely pubescent with fine,
loosely ascending to spreading, minutely pustular-based hairs, these not hooked
at the tip. Inflorescences not paired, the spikelike racemes sometimes
aggregated into few-branched panicles, the flowers with stalks 0.5–2.0
mm long at flowering, elongating to 2–4 mm at fruiting and loosely
ascending (angled away from the axis) at fruiting with a noticeable bend or
curve at the tip, the inflorescence with linear to narrowly oblong, leaflike
bracts at the branch points and lowermost flowers. Calyces 1.5–2.5 mm
long at flowering, elongating to 5–8 mm at fruiting, slightly
zygomorphic at flowering but becoming nearly 2-lipped at fruiting, 5-lobed
slightly less than (shorter teeth) to slightly more than (longer teeth) 1/2 of
the way to the base, the 3 upper lobes shorter than the 2 lower lobes,
especially at fruiting, triangular to narrowly triangular, densely pubescent
with spreading, stiff hairs that are hooked at the tip. Corollas 2–3 mm
long, broadly funnelform to trumpet-shaped, the tube 1.4–2.0 mm long,
the spreading portion 1–2 mm in diameter (measured across the tips of
the lobes), white or rarely pale blue. Stamens inserted below the midpoint of
the corolla tube. Style 0.2–0.3 mm long, shorter than the nutlets.
Nutlets 1.5–2.2 mm long, greenish brown to dark brown.
Scattered in the
southeastern and southwestern portions of the state, uncommon north of the
Missouri River (eastern U.S. west to Missouri and Texas; Canada). Bottomland
prairies, upland prairies, bases and ledges of bluffs, swamps, bottomland
forests, and mesic upland forests; also pastures, fallow fields, railroads,
roadsides, and open, disturbed areas.
have considered M. macrosperma a variety of the closely related M.
verna (Steyermark, 1963), but Al-Shehbaz (1991) argued forcefully against
this interpretation. In Missouri, it is the less common of the two and
apparently is unable to colonize drier sites as efficiently as M. verna.
Although the two taxa can be difficult to distinguish at flowering, the
pubescence of the calyx appears to separate them reliably, as noted in the key
to species above. At fruiting, M. macrosperma tends to be a more robust
plant than is M. verna and has more open, elongated racemes (the fruits
spaced 10–30 vs. 5–9 mm apart, as measured between the bases of
adjacent stalks). The orientation of the stalks at fruiting also is a reliable
character, but care must be taken not to misinterpret it in poorly pressed or