164. Oreochrysum Rydberg, Bull. Torrey Bot. Club. 33: 152. 1906.
[Greek oreios, of mountains, and chrysos, gold]
Guy L. Nesom
Haplopappus Cassini sect. Oreochrysum (Rydberg) H. M. Hall; Solidago Linnaeus subg. Oreochrysum (Rydberg) Semple
Perennials 15–60(–100) cm; rhizomes long, slender, scale-leaved, thickening, becoming woody. Stems erect, usually simple, minutely puberulous or hirtellous, stipitate-glandular. Leaves basal and cauline (basal and proximal cauline persistent); alternate; petiolate to subpetiolate; basal and proximal cauline blades 1-nerved, spatulate-oblanceolate, mid and distal elliptic to broadly ovate-lanceolate or oblanceolate, margins entire (apices acute to obtuse or rounded), minutely, short-stipitate-glandular or gland-dotted, viscid. Heads radiate, in distinctly flat-topped, tightly corymbiform arrays. Involucres campanulate to hemispheric, 10–11 × 6–8 mm. Phyllaries 15–24 in 3–4 series, mostly appressed, 1-nerved (rarely with lateral pair; convex proximally, flat beyond), outer lanceolate to ovate, inner broadly lanceolate-oblong, strongly unequal to subequal, herbaceous, slender (apices green-tipped and erect to reflexing), glabrous or hirtellous, minutely stipitate-glandular, non-resinous. Receptacles flat, pitted , epaleate. Ray florets 12–20, pistillate, fertile; corollas yellow. Disc florets 25–37, bisexual, fertile; corollas yellow, tubes shorter than narrowly tubular-funnelform throats, lobes 5, erect to spreading, triangular; style-branch appendages linear. Cypselae fusiform, plump but distinctly compressed, nerves 12–16 (whitish, raised), glabrous; pappi persistent, of 40–60, equal, barbellate, apically attenuate bristles in 2(–3) series. x = 9.
Species 1: w North America, n Mexico.
Oreochrysum often has been treated as Solidago parryi; J. C. Semple et al. (1999) placed Oreochrysum at subgeneric rank within Solidago. Oreochrysum is separated from Solidago on the basis of its stipitate-glandular vestiture, large heads in strongly corymbiform arrays, herba-ceous phyllaries, prominent rays, narrow disc corollas with relatively short lobes, linear-lanceolate style-branch appendages, and large cypselae. It has no apparent close relatives within Solidago.