Slender Snakecotton

The current range of Froelichia gracilis is due in large part to its introduction via railroads during the past 100 years, and the majority of records for the species east of the Mississippi River occur on or near railroads. S. F. Blake (1956) discussed this eastern spread of the species. Froelichia gracilis is considered a minor invasive weed in the Northeast; its adaptation to open sandy or gravely soils will restrict its spread to open sites with poor soil.

In regions where their ranges overlap, Froelichia gracilis may hybridize with F. floridana. Plants with intermediate form from Texas and the Midwest have been noted. Suspected hybrids appear closest in habit to F. gracilis and will generally key to that species. Floral structure will be intermediate and variable; the branching will be typically less than in F. gracilis and present distal to the base.

Plants annual or short-lived perennial; taproots narrow, enlarged when perennial, semiwoody. Stems several (rarely 1), erect or ascending, sometimes procumbent, usually much-branched from base, slender, 1-5(-10) dm, densely or sparsely villous-tomentose with grayish white hairs. Leaves predominant on proximal ¹/3 of plant, often basal, sessile; blade linear to lanceolate or lance-elliptic, largest leaves 1.6-9(-13.5) × 0.2-0.9(-1.2) cm, base acuminate or attenuate, apex acute to acuminate, canescent or sericeous adaxially, sericeous-tomentose with white or gray hairs abaxially. Spikes sparsely branched, flowers arranged in 3-ranked spiral; bracteoles stramineous or blackish, glabrous. Flowers 2.4-3.8 mm; perianth lobes oblong-linear, apex acute or acutish, pubescence grayish; filament lobes stramineous or blackish, blunt. Utricles 2.5-5 × 2.7-4 mm, apex slightly oblique, with irregularly and deeply cut ("spiny") lateral wings, both surfaces of perianth with distinct spines or tubercles. 2n = 54.

Flowering summer in north, year-round in extreme south. Open plains, rocky hillsides, roadsides, waste ground, railroad ballast; Ont.; Ala., Ariz., Ark., Calif., Colo., Conn., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Miss., Mo., Nebr., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va., Wis.; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas); introduced in Europe; Asia (Japan).

Oplotheca gracilis Hooker, Icon Pl. 3: plate 256. 1840; Froelichia braunii Standley; F. texana (A. Braun) Small 1903, not J. M. Coulter & Fisher 1892; Oplotheca texana A. Braun

Froelichia gracilis (Hook.) Moq. in DC. Prodr. 13 2 : 420. 1849
Oplotheca gracilis Hook. Ic. under pi. 256. 1840.
Froelichia fioridana Uline & Bray, Bot. Gaz. 20: 338, in part. 1895.
Slender, erect or ascending, sometimes procumbent annual, much branched at the base; stems simple or branched, 2-6 dm. long, densely or sparsely villous-tomentose, sometimes viscid above; leaves short-petiolate, the blades linear to lanceolate or lance-elliptic, 3-12 cm. long, 2-7 mm. wide, acute to long-acuminate at the apex, acuminate or attenuate at the base, canescent or sericeous on the upper surface, sericeous or tomentose beneath with white or gray hairs; spikes slender or stout, 1-3 cm. long; bracts acuminate, fuscous or stramineous; bractlets stramineous or fuscous ; calyx-lobes oblong-linear, acute or acutish ; calyxtube with 2 lateral rows of distinct spines at maturity, the sides of the tube tuberculate near the base; seed 1.5 mm. long, yellowish-brown, shining.
Type ujcality: Texas. « , , „ ^ « . * , a a PL-
Distribution; In dry soil, Iowa to Colorado, and southward to Arkansas, Arizona, and Cni-

Froelichia braunii Standley
Froelichia floridana Moq. in DC. Prodr. 13 2 : 420, in part. 1849.
Oplotheca texana A. Br. Ann. Sci. Nat. III. 12: 355. 1849.
Froelichia texana A. Br.; Small, Fl. SE. U. S. 397. 1903. Not F. texana Coult, & Fisher, 1892.
Slender, erect or ascending annual, branched at the base; stems simple or branched, pubescent with short appressed brownish hairs, somewhat viscid above, usually villous-tomentose near the base; petioles of the lower leaves often half as long as the blades, the upper leaves short-petiolate ; leaf -blades linear to linear-elliptic or narrowly lanceolate, 2-12 cm. long, 0.2-2.2 cm. wide, acute to long-acuminate at the apex, acuminate or attenuate at the base, canescent to sericeous-tomentose beneath with brownish or grayish hairs; spikes dense, stout, 0.5-2 cm. long; bracts acute or acuminate, fuscous or stramineous; bractlets stramineous or fuscous; calyx-lobes lance-oblong, acute or acutish; calyx-tube with 2 lateral rows of distant spines at maturity, the sides of the tube each with 1 or more sharp spines; seed 1.5 mm. long, brown, shining.
Type i/dcality: Texas.
Distribution: Dry soil, Texas; adventive near St. Louis, Missouri.