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FNA | Family List | FNA Vol. 21 | Asteraceae

248. Dicoria Torrey & A. Gray in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 86, plate 30. 1859.

[Greek di, two, and koris, bug, alluding to the two, "buglike" cypselae of the original species]

John L. Strother

Annuals, perennials, or subshrubs [shrubs], 10–90+ cm. Stems erect, virgately to divaricately branched. Leaves cauline; proximally opposite (first 2–10+ pairs in early growth, Feb–Apr), otherwise alternate; petiolate; blades (3-nerved) lance-linear to lanceolate (proximal) or ± deltate or ovate to elliptic or lanceolate (distal), margins entire or toothed, faces sericeous to strigillose, sometimes with coarser, erect hairs, usually gland-dotted as well. Heads disciform or discoid (then functionally staminate), in (mostly ebracteate) racemiform to paniculiform arrays [borne singly or loosely aggregated in 2s or 3s]. Involucres ± cup-shaped to saucer-shaped, 3–5+ mm diam. Phyllaries persistent (outer) or tardily falling, distinct, outer (4–)5(–7) in 1 series, ± herbaceous, inner 0–4 (each subtending a pistillate floret), scarious to membranous (accrescent, ultimately ovate to elliptic in fruit). Receptacles convex; paleae cuneiform to linear, membranous, ± villous to hispid distally, sometimes wanting. Pistillate florets (0–)1–4; corollas 0. Functionally staminate florets 5–15+; corollas whitish, funnelform, lobes 5, erect, reflexed, or incurved (anthers distinct or weakly coherent). Cypselae strongly obcompressed, often slightly cucullate, ± obovate to elliptic, margins corky-winged, irregularly toothed, faces smooth or warty, sometimes gland-dotted; pappi 0 (cypselae often each with apical tuft of white hairs). x = 18.

Species 2 (1 in the flora): w North America, nw Mexico.

Traits that have been used to distinguish species and/or infraspecific taxa of dicorias in the flora (presence/absence of erect hairs on stems, shape, size, and toothing of distal leaves, size of cypselae, and relative development of inner phyllaries; A. Cronquist 1994) vary and combine so capriciously that I find no justification for recognition of more than a single, polymorphic species in the flora area.

Lower Taxon


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