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FNA | Family List | FNA Vol. 5 | Polygonaceae | Eriogonum

1f. Eriogonum Michaux subg. Pterogonum (H. Gross) Reveal, Sida. 3: 82. 1967.

Pterogonum H. Gross, Bot. Jahrb. Syst. 49: 239. 1913

Herbs, erect, polycarpic or monocarpic perennials, strigose, silky-pubescent, or glandular-puberulent, occasionally glabrous [tomentose]; taproot woody occasionally chambered. Stems erect, with persistent leaf bases, silky-pubescent to glandular-puberulent or glabrous; caudex absent or compact, spreading; aerial flowering stems erect, slender to stout, solid or hollow, sometimes fistulose, not disarticulating in ringlike segments proximally, usually arising directly from root. Leaves persistent or marcescent, basal or basal and cauline, not fasciculate; blade glabrous or strigose to hispid or stipitate-glandular.  Inflorescences cymose, open, occasionally with 1 branch of cyme suppressed; bracts 3, connate basally, semileaflike to scalelike. Peduncles ascending to erect, slender. Involucres 1 per node, not appressed to inflorescence branches, turbinate to campanulate; teeth 5, erect. Flowers not attenuate at base, without stipelike base; perianth various shades of white, yellow, red, or purple, glabrous on both surfaces or occasionally pubescent abaxially; tepals connate proximally 1/ 1/ 3 their length, monomorphic; stamens exserted; filaments pilose proximally or glabrous. Achenes various shades of brown, 3-winged or -ridged, 3-gonous, glabrous or pilose [strigose]. Seeds: embryo straight.

Species 11 (6 in the flora): sw United States, Mexico.

W. J. Hess and J. L. Reveal (1976) subdivided subg. Pterogonum into four sections: sect. Pterogonum (only Eriogonum atrorubens in the flora area), sect. Peregrina W. J. Hess & Reveal (E. greggii), sect. Astra W. J. Hess & Reveal (E. hemipterum, E. hieracifolium, and E. nealleyi), and sect. Alata Bentham (E. alatum). The rest of the species occur in northern Mexico and all belong to sect. Pterogonum: E. ciliatum Torrey ex Bentham, E. clivosum W. J. Hess & Reveal, E. fimbriatum W. J. Hess & Reveal, E. henricksonii Reveal, and E. viscanum W. J. Hess & Reveal.


Hess, W. J. and J. L. Reveal. 1976. A revision of Eriogonum (Polygonaceae) subgenus Pterogonum. Great Basin Naturalist 36: 281-333.

1 Leaves basal or, if cauline, whorled; stems glandular-puberulent or, if glabrous, stems fistulose   (2)
+ Leaves basal; stems strigose to glandular-pubescent or, if glabrous, stems not fistulose   (3)
2 (1) Perianths glabrous, purple to red or maroon; cauline leaves absent; stems glabrous, often fistulose; Hidalgo County, New Mexico   141 Eriogonum atrorubens
+ Perianths strigose, yellowish white; cauline leaves whorled; stems glandular-puberulent, not fistulose; Hidalgo County, Texas   142 Eriogonum greggii
3 (1) Plants monocarpic; taproot often chambered; perianths yellow to yellowish green, rarely maroon in anthesis; achenes winged entire length; e Utah, se Wyoming and sw Nebraskato n Arizona, New Mexico, and n and w Texas   146 Eriogonum alatum
+ Plants polycarpic; taproot not chambered; perianths yellow, white to greenish white, reddish purple, or maroon; achenes ribbed or winged only along distal 1/ 2; ec Arizona, wc and s New Mexico, w Texas   (4)
4 (3) Inflorescence branches glabrous; perianths white to greenish white, glabrous or sparsely strigose; Coke, Howard, Irion, and Sterling counties, Texas   144 Eriogonum nealleyi
+ Inflorescence branches strigose; perianths yellow to reddish purple or maroon, strigose or pilose; ec Arizona, wc and s New Mexico to sw Texas   (5)
5 (4) Perianths reddish purple or maroon, rarely yellow; Brewster County, Texas   143 Eriogonum hemipterum
+ Perianth yellow in anthesis, reddish in fruit; ec Arizona, wc and s New Mexico to w Texas   145 Eriogonum hieracifolium


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