Oreochrysum

Rydberg

Bull. Torrey Bot. Club 33: 152. 1906.

Etymology: Greek oreios, of mountains, and chrysos, gold
Synonyms: Haplopappus sect. Oreochrysum (Rydberg) H. M. Hall Solidago subg. Oreochrysum (Rydberg) Semple
Treatment appears in FNA Volume 20. Treatment on page 166. Mentioned on page 15, 108, 167.

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.

Distribution

w North America, n Mexico.

Discussion

Species 1.

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, herbaceous 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.

Selected References

None.

Lower Taxa