Tetragonotheca
Family: Asteraceae
Images
not available

Perennials, mostly 30-120 cm. Stems erect. Leaves basal and/or cauline; mostly opposite; petiolate, subpetiolate, or sessile (bases sometimes connate-perfoliate); blades lanceolate, ovate, rhombic, or rounded-deltate, sometimes pinnatifid, ultimate margins usually toothed, faces glabrate, sparsely hispidulous, or puberulent, gland-dotted. Heads radiate, borne singly or in loose, corymbiform arrays. Involucres obpyramidal to hemispheric, 12-25+ mm diam. Phyllaries persistent, 10-25+ in ± 2 series (outer 4 broadly lanceolate, foliaceous, the inner ovate to lanceolate, smaller, more scarious, each subtending a ray floret). Receptacles conic, paleate (paleae persistent, lanceolate to lance-ovate, flat or weakly conduplicate, apices acute). Ray florets 6-21+, pistillate, fertile; corollas yellow (often with reddish nerves). Disc florets 25-150+, bisexual, fertile; corollas yellow, tubes (basally dilated) much shorter than ampliate, cylindric throats, lobes 5, deltate. Cypselae ± ovoid or plumply 4- or 5-angled, finely 32-40-ribbed, sparsely strigose or glabrous; pappi 0, or of 1-10+ subulate to acerose scales (to 0.5 mm), or of 16-30, ± spatulate scales (0.5-2 mm). x = 17.

Heads radiate, the rays pistillate and fertile, light yellow; invol of 4(5) relatively large and leafy bracts, united at base; receptacle conic, especially in fr, its bracts subtending rays as well as disk-fls, thin, partly clasping the achenes; disk-fls perfect and fertile, the cor-tube expanded at base and covering the top of the achene; style-branches flattened, with rather long, hairy appendage; achenes quadrangular or subterete, scarcely compressed; pappus of several short scales, or none; coarse, taprooted perennial herbs with clustered stems, opposite, ±toothed, often clasping lvs and few or solitary heads. 4, U.S., Mex.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.

Images
not available
Map not
Available
Images
not available
Map not
Available
Images
not available
Map not
Available
Images
not available
Map not
Available