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

1a. Eriogonum Michaux subg. Eucycla (Nuttall) Kuntze in T. E. von Post and O. Kuntze, Lex. Gen. Phan. 204. 1903.

Eucycla Nuttall, Proc. Acad. Nat. Sci. Philadelphia 4: 16. 1848

Shrubs, subshrubs, or herbs, sometimes nearly arborescent, perennial, glabrous or pubescent, rarely glandular; taproot woody. Stems matted to spreading, decumbent, or erect, infrequently absent, with or without persistent leaf bases, glabrous or variously pubescent or glandular; caudex stems woody, tightly compact to spreading and at or just below surface, or spreading to erect and above surface; aerial flowering stems arising at nodes of caudex branches, at distal nodes of aerial branches, or directly from root, prostrate or decumbent to erect, slender to stout and usually solid, infrequently slightly to distinctly fistulose and hollow. Leaves basal, sometimes in rosettes, sometimes sheathing up stems, cauline, or basal and cauline, 1 per node or fasciculate on flowering stems, at tips of dwarf branches, or on exposed woody caudices, usually persistent, occasionally persistent through growing season or longer, rarely quickly deciduous; blade glabrous or floccose to tomentose, occasionally also glandular. Inflorescences cymose, cymose-umbellate, umbellate, virgate, or racemose, mostly spreading and open to diffuse, sometimes dense, congested, or compact, sometimes reduced and in subumbellate, subcapitate, or capitate heads or reduced to a single terminal involucre; branches open to diffuse, spreading to erect, usually dichotomously branched except for initial trichotomous node, round and smooth, rarely grooved, angled, or ridged, tomentose to floccose or glabrous, occasionally lanate or glandular, rarely scabrellous; bracts usually 3, connate basally, usually scalelike, sometimes semileaflike or leaflike. Peduncles absent or erect, usually stout. Involucres 1-8 or more per cluster, narrowly turbinate to campanulate; teeth (3-)5-6(-10), erect or occasionally spreading, apex acute to obtuse or rounded. Flowers bisexual or, infrequently, unisexual, not attenuate at base, without stipelike base (except for slightly winged stipelike bases in E. saxatile and E. crocatum); perianth various shades of white, yellow, pink, or red, glabrous, glandular, or variously pubescent abaxially, usually glabrous adaxially except for minute glands and a few scattered hairs; tepals connate only basally or in proximal 2, monomorphic or dimorphic; stamens usually exserted, sometimes included; filaments variously pubescent but usually pilose proximally, infrequently glabrous. Achenes light to dark brown, not winged (but nearly so in E. saxatile), 3-gonous, glabrous, occasionally with minutely papillate beak. Seeds: embryo curved.

Species 107 (101 in the flora): w North America (including nw Mexico), mainly arid regions.

Species of subg. Eucycla not accounted for in this treatment are: Eriogonum encelioides Reveal & C. A. Hanson, E. fastigiatum Parry, E. molle Greene, E. orcuttianum S. Watson, E. pondii Greene, and E. zapatoense Moran. All are native to Baja California, Mexico.

The keys to species for subg. Eucycla are broken into geographic regions to aid in identification. They are: California (key 1, p. 225); British Columbia, Idaho, Oregon, and Washington (key 2, p. 228); Nevada and Utah (key 3, p. 231); Arizona and New Mexico (key 4, p. 237); Alberta, Colorado, Montana, and Wyoming (key 5, p. 239); and Manitoba, Saskatchewan, Great Plains states, and Texas (key 6, p. 242).

Key 6—Manitoba, Saskatchewan, Great Plains States, and Texas

1 Plants shrubs or subshrubs   (2)
+ Plants herbs   (6)
2 (1) Tepals strongly dimorphic; w Texas   95 Eriogonum suffruticosum
+ Tepals monomorphic; Great Plains, including Texas   (3)
3 (2) Leaf blades linear to linear-oblanceolate, 0.1-0.3 cm wide; wc Kansas   3 Eriogonum helichrysoides
+ Leaf blades oblanceolate to oblong, elliptic or obovate, 0.2-2.5 cm wide; widespread   (4)
4 (3) Leaf blades (1-)1.5-2.5 cm wide; Deaf Smith County, Texas   16 Eriogonum corymbosum
+ Leaf blades 0.2-0.7 cm wide; widespread   (5)
5 (4) Inflorescences cymose, with involucres not racemosely arranged; leaves not fasciculate; n Great Plains   2 Eriogonum effusum
+ Inflorescences virgate or somewhat cymose, with involucres racemosely arranged; leaves often fasciculate; w Texas   72 Eriogonum wrightii
6 (1) Perianths glabrous; n Great Plains   (7)
+ Perianths pubescent; Great Plains or Texas   (8)
7 (6) Perianths usually yellow, rarely white or cream   27 Eriogonum brevicaule
+ Perianths whitish brown to rose   64 Eriogonum pauciflorum (in part)
8 (6) Perianths whitish brown to rose, sparsely pubescent; plants loosely matted; n Great Plains   64 Eriogonum pauciflorum (in part)
+ Perianths yellow, densely white-pubescent; plants not matted; s Great Plains or Texas   (9)
9 (8) Achenes villous to tomentose; sw Kansas, w Oklahoma, Texas   69 Eriogonum lachnogynum
+ Achenes glabrous; w Texas   70 Eriogonum havardii

List of Keys


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