Pluchea sagittalis
Pluchea sericea
wing-stem camphorweed
arrow-weed
minutely hirtellous to strigillose and sessile-glandular (winged by decurrent leaf bases).
(densely leafy) sericeous, not glandular.
sessile;
blades usually lanceolate to lance-elliptic (proximal sometimes spatulate or oblanceolate), mostly 5–15 × 1–3(–4) cm, margins shallowly and closely toothed, faces minutely hirtellous to strigillose and sessile-glandular.
sessile;
blades lanceolate to narrowly lanceolate or narrowly oblanceolate, 1–5 × 0.2–1 cm, margins entire, faces sparsely to densely silvery sericeous, not glandular (minutely punctate).
hemispheric to cupulate, 4–7 × 8–10 mm.
± campanulate, 4–6 × 3–5 mm.
white or rose-purple.
pink to purplish.
greenish to cream, ± stipitate-glandular (outer oval-oblong to linear-attenuate).
pink to purplish, tomentose to villosulous (outer) to arachnose-ciliate or glabrate (inner).
in corymbiform arrays.
in cymiform clusters.
persistent, bristles distinct.
persistent, bristles distinct (distally dilated in functionally staminate florets; cypselae glabrous).
= 20.
= 20.
Pluchea sagittalis
Pluchea sericea
Pluchea sagittalis is adventive, probably a waif; it was collected as a ballast weed by C. Mohr near Mobile (1891, 1894, 1896) and by A. H. Curtiss near Pensacola (1886, 1901).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Pluchea sericea (with its woody habit and eglandular, densely arranged, sericeous leaves) is isolated among North American Pluchea. Torrey and Gray recognized its close similarity to the Asian Pluchea lanceolata (de Candolle) Oliver & Hiern, the type species of the Asian genus Berthelotia. It has been treated within Berthelotia and the South American and Central American segregate Tessaria, and a distinct genus (Eremohylema A. Nelson) has been created for it.
Pluchea sericea is more similar to the segregates than to herbaceous American groups; the delimitations of the genera are not clear. Tessaria was restricted to T. integrifolia Ruiz & Pavón, based on its single functionally staminate flower per head and corolla lobes cut nearly to the base of the limb, by H. Robinson and J. Cuatrecasas (1973). The sister species of T. integrifolia appears to be T. absinthoides (Hooker & Arnott) Cabrera [= Pluchea absinthoides (Hooker & Arnott) H. Robinson & Cuatrecasas]. Both species have inner phyllaries with reflexing tips, alveolate and paleate receptacles, pappus bristles basally united into a thick cup, and other distinctive floral features (G. L. Nesom 1989). It seems likely that the accepted definition of Tessaria may be expanded to two species or more broadly to include P. sericea and the species placed in Berthelotia. Alternately, Berthelotia (including P. sericea) might be accepted at generic rank, coordinate with Tessaria. In any case, it seems likely that P. sericea ultimately will be treated outside a more strictly circumscribed Pluchea.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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