2b. ssp. uninervia (J. Presl) N. Snow

L. uninervia (J. Presl) Hitchc. & Chase (Mexican sprangletop)

Leaf sheaths with the ligules 0.5–2.0 mm long. Inflorescences with the base usually positioned above the uppermost leaf sheath. Lower glume 1.0–2.6 mm long. Upper glume 1.8–2.8 mm long, ovate to obovate. Lemmas 2.3–3.6 mm long, elliptic‑ovate, bluntly pointed to rounded or truncate at the tip, sometimes minutely notched. Anthers 0.4–1.0 mm long. Fruits 1.0–1.5 mm long. 2n=20. August–September.

Introduced, known only from St. Louis (southern U.S., Mexico, Central America, South America, Caribbean Islands). Railroads.

The Missouri specimens of ssp. uninervia were first reported for the state by Snow (1997) and originally had been misdetermined as other taxa of Leptochloa. The northern limits of the native distribution of this subspecies are poorly understood, and many of the collections from the United States are from disturbed habitats. In addition to the differences in the key above, ssp. uninervia may be distinguished from ssp. fusca by its grayish “lead‑colored” (vs. green or purplish green) spikelets.