Red River Scaleseed

Spermolepis inermis (Nutt.) Math. & Const. Bull. Torrey Club 68: 124. 1941.
Leptocaulis inermis Nutt.; DC. Coll. Mem. S: 39. 1829.
Leptocaulis patens Nutt.; DC. Coll. Mem. 5: 39. 1829 (nomen nudum); Prodr. 4: 107. 1830.
Apium patens S. Wats. Bibl. Ind. 413. 1878.
Apiaslrum patens Coult. & Rose, Rev. N. Am. Umbell. 110. 1S88.
Spermolepis patens B.L. Robinson, Rhodora 10: 34. 1908.
Spermolepis patens var. inermis Mathias, Brittonia 2: 243. 1936.
Slender, erect, 0.8-6 dm. high; leaves oblong-ovate in general outline, excluding the petioles 3-5 cm. long, 2-4 cm. broad, ternately decompound, the ultimate divisions filiform, mucronulate, 3-30 mm. long, 0.1-1 mm. broad; petioles 4-15 mm. long; peduncles 2-7 cm. long; involucel of a few narrow bractlets, callous-toothed to glabrous, shorter than the pedicels; rays 5-11, erect, unequal, 1-13 mm. long; pedicels 1-6, up to 6 mm. long, the central umbellets bearing 1-3 sessile or shortly pediceled flowers; fruit ovoid, 1.5-2 mm. long, about 1.5 mm. broad, tuberculate to smooth.
Type locality: "In Amer. bor. ad Red River," Arkansas, Nuttall.
Distribution: Illinois to Mississippi, west to Nebraska, Texas, and Coahuila (Bush 5864, 7602, Palmer 7713, 33,614).

Spermolepis inermis, the Red River scaleseed or spreading scaleseed, is a species of flowering plant in the family Apiaceae. It is native to the central and southeastern United States, and eastern Mexico. An annual reaching 3 ft (1 m), it is found in grasslands.