Annuals, 8-45(-55) cm; taprooted or fibrous-rooted. Stems erect, ascending (usually branched ± throughout), subpannose (hairs silver-gray, longitudinally arranged). Leaves mostly cauline, basal usually withering before flowering, blades spatulate to oblanceolate, mostly 2-6 cm × 2-9 mm (becoming linear-oblanceolate to linear distally, commonly folded along midveins), faces concolor or weakly bicolor, subpannose (hairs closely appressed). Heads initially in continuous or interrupted, spiciform arrays, 2-4 cm × 8-12 mm (pressed), later in paniculiform arrays 4-18 cm (main axes usually visible between heads, peduncles usually evident). Involucres campanulate, 3-3.5 mm, bases usually glabrous or glabrate. Phyllaries in 5-7 series, outer ovate-triangular, lengths 1/3-1/2 inner, apices acute-acuminate (involute and spreading to recurved), inner oblong, laminae slightly brown (not purple), apices obtuse-apiculate. Florets: bisexual 2-4; all corollas purple distally. Cypselae (tan) 0.4-0.5 mm. Flowering (Apr-)May-Jul. Disturbed sites, sandy or clay soils, roadsides, fields, clearing and edges of woods, flower beds; 0-500 m; Ala., Ark., Calif., La., Miss., N.C., Okla., S.C., Tex., Va.; South America; Europe; Pacific Islands (New Zealand). Gamochaeta calviceps is recognized by its subpannose cauline and foliar indument (perhaps intermediate between the looser tomentum of G.antillana and the tight, pannose covering of G. argyrinea) and the contrast of its spatulate proximal leaves with the much narrower cauline ones, glabrous or glabrescent involucres, and phyllaries in 5-7 series, lacking purple color, the outer and mid with acute-acuminate apices commonly becoming subulate (by inrolled margins). The distal cauline leaves usually are folded along the midveins (at least when pressed). The relatively late flowering also is distinctive. Plants on the Atlantic coastal plain usually produce 2-3 bisexual florets per head, those on the Gulf coast 3-4.
Heads of older plants are borne in paniculiform arrays resulting from development of lateral branches, the heads usually on evident peduncles and with very little tomentum at the base of the outer phyllaries, thus appearing discrete. In early-season plants, lateral branches may not have formed or lengthened and the arrays of heads may appear continuous-cylindric at stem apices; in such plants, the species can usually still be recognized by the relatively numerous, relatively shorter, axillary shoots along the main stems.
FNA 2006, Kearney and Peebles 1969, McDougall 1973
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Herbaceous annual, erect, ascending, branching throughout, herbage wooly, with silver-gray hairs longitudinally arranged, taprooted or fibrous-rooted. Leaves: Alternate, entire, mostly cauline, blades spatulate to oblanceolate, mostly 2-6 cm long and 2-9 mm wide, becoming linear-oblanceolate to linear distally, commonly folded along midveins, wooly with silver-gray appressed hairs, basal leaves usually withering before flowering. Flowers: Heads discoid, the outer flowers slender and pistillate, the inner ones coarser and perfect, all fertile, apices obtuse-apiculate, corollas purple distally, involucres ovoid or campanulate, receptacles naked, the phyllaries in 5-7 series, slightly to evidently overlapping, dry and membranaceous, the outer ovate to triangular, the inner oblong, with acute or acuminate apices, reflexed, inflorescences borne in panicles, corymbs, or spikes. Fruits: Achenes tan, to 0.5 mm. Pappus of capillary bristles. Ecology: Found in disturbed sites, sandy or clay soils, roadsides, fields, clearing and edges of woods, and flower beds, from 0-2,000 ft (0-610 m); flowering May-July. Distribution: Occuring in the southern-most portions of the United States, from California, Arizona, New Mexico, and Texas, stretching east to Virginia and North Carolina. Notes: Look for this species under Gnaphalium purpureum var. falcatum or Gnaphalium calviceps in older texts. Ethnobotany: Unknown Etymology: Gamochaeta is from Greek gamos, marriage, stigma, or female part, and chaite, bristle, mane, long hair, while falcata means sickle shaped. Synonyms: Many, see Tropicos Editor: LCrumbacher 2011