Froelichia floridana (Nutt.) Moq.

Froelichia floridana ranges from broad-leaved stout herbs surpassing 1 meter in height to much-branched plants forming bushes to 2 meters in diameter and single-stemmed, erect herbs 1 dm in height. Much of the variation in the species has been difficult to ascribe to either geographic or ecologic differences and reflects inherent genetic variability and wide environmentally induced plasticity. Although specialists and taxonomists have implied the existence of well-delineated morphologic taxa with a strong geographic correspondence, this is not always true, and, in fact, one encounters typical specimens of any given variety sporadically throughout the range of the species.

Some variability in Froelichia floridana is clearly attributable to geography, principally in terms of general morphologic trends. There is a cline toward long, narrow, almost linear leaves as one moves east along the Gulf Coast and into Florida. This would culminate in the little-known var. pallescens Moquin-Tandon, a linear-leaved form (leaf length more than eight times width) from peninsular Florida. Additional variation ascribable to geography is observed in plants traditionally included in F. drummondii, these being large, stout plants with broader leaves, more obtuse leaf apices, and more densely fulvous pubescence on the abaxial surfaces of leaves. Plants of this form are generally restricted south of the Brazos River and continue to the southern extent of the range in Kenedy County, Texas. Further work examining this variation using micromorphology or molecular markers may elucidate a reliable means to identify intraspecific taxa within F. floridana.

Plants annual; taproots semi-woody. Stems 1, erect or ascend-ing, sometimes procumbent, simple or sparsely branched (rarely much-branched) from base or above, stout, to 18 dm, puberulent or tomentulose with short, viscid, whitish or brownish hairs. Leaves principally on proximal ¹/3 of plant, petiolate; blade lanceolate to oblanceolate, oblong, or linear, largest leaves 3.8-11.2(-21) × 0.5-3.8(-4.2) cm, base attenuate to cuneate, apex acute to obtuse, canescent to subscabrous adaxially, sericeous-tomentose abaxially. Spikes dense, much-branched, apex often pyramidal, flowers arranged in 5-ranked spiral; bracteoles stramineous or blackish, pubescent with small tufts distally. Flowers 4-6 mm; perianth lobes, greenish white to pinkish, oblong, apex acute; filament lobes slightly to greatly recurved distally, stramineous to pinkish, apex acute. Utricles flask-shaped, 5 × 4-5 mm, with irregularly dentate lateral wings, both surfaces of perianth with distinct spines or tubercles. 2n = 58 + 2.

Flowering summer. Open sand prairies, edges of woodlands in sandy soils, roadsides, railroad rights-of-way; Ala., Ark., Colo., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mich., Minn., Miss., Nebr., N.C., N.Dak., Ohio, Okla., S.C., S.Dak., Tex., Wis.; West Indies; introduced in Australia.

Oplotheca floridana Nuttall, Gen. N. Amer. Pl. 2: 79. 1818; Froelichia campestris Small; F. floridana var. campestris (Small) Fernald; F. floridana var. pallescens Moquin-Tandon

Froelichia floridana (Nutt.) Moq. in DC. Prodr. 13 2 : 420. 1849
Oplotheca floridana Nutt. Gen. 2: 79. 1818.
Gomphrena floridana Spreng. Syst. 1: 824. 1825.
Froelichia floridana pallescens Moq. in DC. Prodr. 13 2 : 421. 1849.
Froelichia gracilis floridana Holz. Contr. U. S. Nat. Herb. 1: 197. 1892.
Stout, erect or ascending annual; stems usually simple at the base, 3-18 dm. high, the branches puberulent or tomentulose with short, often viscid, whitish or yellowish hairs; leaves very shortly petiolate, the blades oblong-linear to narrowly lanceolate, 3-12 cm. long, 0.4-1.5 cm. wide, acute or acuminate at both ends, scaberulous or canescent on the upper surface, sericeous beneath with usually yellowish hairs; spikes 1-7 cm. long, dense, stout; bracts stramineous or fuscous, acuminate or cuspidate; bractlets stramineous or fuscous; calyx-lobes oblong, obtuse, greenishwhite or pinkish; calyx-tube winged along the sides, the wings thick and firm, deeply dentate, the sides with 1 or 2 spiny or tuber culate ridges near the base; seed brown, 1.5 mm. long.
Type locality: On the banks of the Altamaha River, Georgia.
Distribution: In sandy soil, southern Georgia and Florida to Mississippi; Delaware, perhaps adventive.

Froelichia floridana is a species of flowering plant in the genus Froelichia, in the amaranth family (Amaranthaceae). It is known as prairie cottonweed, Florida snakecotton, large cottonweed, field snakecotton, or plains snakecotton. An annual, it produces white woolly flowers on tall flowering stalks, growing up to 40 in (1,000 mm) in height. The narrowly oblanceolate to elliptic leaves are opposite, occurring on the lower third of the stem. It grows in central and eastern North America, from the Great Plains to Mexico, east to the Atlantic Coast. Its propensity to spread easily has resulted in it being considered an agricultural weed and it is an invasive species in Australia.

Botanical illustration (1840)

Flowerhead

Froelichia floridana là loài thực vật có hoa thuộc họ Dền. Loài này được (Nutt.) Moq. mô tả khoa học đầu tiên năm 1849.