Eriogonum subg. Oligogonum in Flora of North America @ efloras.org

1e. Eriogonum Michaux subg. Oligogonum Nuttall, J. Acad. Nat. Sci. Philadelphia. n. s. 1: 166. 1848. (as Olygogonum).

Herbs, shrubs, or subshrubs, cespitose, matted or spreading to erect, polycarpic perennials, synoecious or polygamodioecious, rarely dioecious, lanate to tomentose, floccose, or glabrous occasionally sericeous; taproot woody. Stems prostrate to erect, with persistent leaf bases, glabrous, pubescent, or glandular; caudex woody, tightly compact to spreading or erect and at or just below surface, or spreading to erect and above surface; aerial flowering stems prostrate or decumbent to erect, slender to stout, usually solid or hollow, sometimes fistulose, not disarticulating in ringlike segments proximally, arising at nodes of caudex branches, at distal nodes of aerial branches or, rarely, directly from the root. Leaves persistent through the growing season or longer, tufted at tips of caudices or whorled at base of stems in rosettes; blade lanate, tomentose, floccose, villous, sericeous, or glabrous. Inflorescences simple- to compound-umbellate, usually open and spreading, occasionally reduced and subcapitate to capitate; branches absent or round and smooth, tomentose to floccose or glabrous; bracts usually 2-10 sometimes more, scalelike, semileaflike, or leaflike. Peduncles absent (or sometimes technically erect and slender, being that portion of “aerial flowering stem” above a whorl of leaflike bracts about midlength; not treated as a distinct structure here). Involucres 1 per node, rarely 2-3 per cluster, not appressed to inflorescence branches,turbinate to campanulate; teeth 5-10 or more, erect or lobelike and spreading to reflexed. Flowers bisexual or unisexual, attenuate at base, stipelike base 0.1-3 mm; perianth various shades of white, cream, yellow, pink, or reddish, glabrous or pubescent abaxially, glabrous adaxially; tepals connate proximally 1/ 1/ 3 their length, monomorphic or dimorphic; stamens usually exserted, occasionally included; filaments pilose proximally, very rarely glabrous. Achenes light to dark brown, not winged, 3-gonous, glabrous or pubescent only on beak. Seeds: embryo straight or curved.

Species 35 (34 in the flora): w North America (including n Mexico).

Only Eriogonum turneri Reveal is not treated here; it is related to E. jamesii var. undulatum, and is known only from gypsum outcrops in Nuevo León, Mexico.

1 Involucral teeth lobelike, at least half as long as tube, usually reflexed or spreading (2)

+ Involucral teeth not lobelike, much shorter than tube, erect or nearly so (14)

2 (1) Perianths pubescent abaxially (3)

+ Perianths glabrous abaxially (8)

3 (2) Flowering stems (actually scapes) without subtending bracts on stem or below involucre; e California to se Oregon, s Idaho, sw Montana, w Wyoming, Nevada, Utah, and nw Arizona 123 Eriogonum caespitosum

+ Flowering stems with whorl of subtending bracts at base of umbel, near middle of stem, or near middle of branches (4)

4 (3) Involucres usually more than 1 per, subtended by (2-)3-several leafy bracts at base of umbel; inflorescences compound-umbellate or umbellate, occasionally with whorl of bracts midlength on central branch of an umbel; flowering stem usually without whorl of bracts near middle (5)

+ Involucre 1 per inflorescence, not immediately subtended by leafy bracts; inflorescences capitate; flowering stems with whorl of bracts near middle (6)

5 (4) Flowers (5-)6-9 mm; perianth bright or pale yellow or ochroleucous to cream; leaf blades lanate to tomentose, floccose, or glabrous on both surfaces; plants 0.5-4 dm; ne California to e Washington, s Idaho, and n Nevada 120 Eriogonum sphaerocephalum

+ Flowers 4-5 mm; perianth bright yellow; leaf blades densely tomentose on both surfaces; plants 2.5-5 dm; n California 117 Eriogonum tripodum

6 (4) Leaf blades tomentose or lanate adaxially; e Washington to n and ec California, and nw and ne Nevada 121 Eriogonum douglasii

+ Leaf blades thinly tomentose to nearly glabrous and green adaxially; widespead (7)

7 (6) Leaf blades usually linear-oblanceolate or narrowly oblanceolate to narrowly spatulate; n California and nw Nevada to sw Idaho, Oregon, and c Washington 120 Eriogonum sphaerocephalum (in part)

+ Leaf blades oblanceolate to elliptic; s Sierra Navada in Tulare County, California 122 Eriogonum twisselmannii

8 (2) Inflorescences capitate, without subtending bracts immediately below involucre; flowering stems with a whorl of leafy bracts ca. midlength; perianths yellow (9)

+ Inflorescence umbellate or compound-umbellate, subtended by leafy bracts immediately below umbel; flowering stems occasionally with an additional whorl of bracts ca. midlength; perianths various shades of white, yellow, or rose (10)

9 (8) Leaf blades 0.5-1.5(-2) cm, densely tomentose on both surfaces, or subglabrous and pale green adaxially; plants erect or rounded herbs or subshrubs, occasionally matted; Sierra Nevada from Nevada County to Frenso County 116 Eriogonum prattenianum (in part)

+ Leaf blades (0.3-)0.5-0.8 cm, sparsely floccose to glabrate and bright green or olive green adaxially; plants matted herbs; Scott Mountain and Mt. Eddy region, Siskiyou and Trinity counties, California 110 Eriogonum siskiyouense

10 (8) Flowering stems usually with whorl of leafy bracts ca. midlength; leaf blades usually linear to oblanceolate; s British Columbia and Washington to w Montana s to ne California, Idaho, n Nevada, Wyoming, c Utah, and nw Colorado 108 Eriogonum heracleoides

+ Flowering stems without a whorl of leafy bracts ca. midlength (present in E. umbellatum var. argus); leaf blades variable; equally widespread, extending to s California and n Arizona (11)

11 (10) Stipelike bases of flowers 0.1-0.4 mm (12)

+ Stipelike bases of flowers 0.7-2 mm (13)

12 (11) Flowers 5-7 mm; achenes 4.5-6 mm; flowering stems prostrate to decumbent or weakly erect; inflorescences subcapitate to umbellate, infrequently 2-umbellate; n California, sw Oregon, and wc Nevada 138 Eriogonum lobbii (in part)

+ Flowers 7-9 mm; achenes 6-8 mm; flowering stems erect or nearly so; inflorescences 2-umbellate; wc Nevada 139 Eriogonum robustum (in part)

13 (11) Leaf blades 0.3-3(-4) cm; flowering stems not fistulose; w North America 107 Eriogonum umbellatum

+ Leaf blades (2-)7-25 cm; flowering stems occasionally fistulose; nw Idaho n to California, Oregon, Washington 109 Eriogonum compositum

14 (1) Perianths pubescent abaxially (15)

+ Perianths usually glabrous abaxially (25)

15 (14) Leaf blades pilose or hirtellous to glabrescent abaxially (16)

+ Leaf blades tomentose abaxially (17)

16 (15) Leaf blades pilose, 1-3(-3.5) cm; perianths cream to pale yellow; flowers 3-6 mm; ec California, wc Nevada 135 Eriogonum latens

+ Leaf blades hirtellous to glabrescent, 0.5-2(-2.5) cm; perianths bright yellow; flowers 3-3.5(-4) mm; Del Norte and Siskiyou counties, California 136 Eriogonum hirtellum

17 (15) Flowering stems with whorl of 6-10(-12) bracts ca. midlength; leaf blades silky-villous to sericeous adaxially; se Washington to ne Oregon and sw Idaho 118 Eriogonum thymoides

+ Flowering stems without whorl of bracts ca. midlength; leaf blades not silky-villous to sericeous adaxially; widespread (18)

18 (17) Perianths white to rose; inflorescences subtended by 2 bracts; flowering stems weakly erect to ascending or prostrate; s British Columbia and Washington to n California to w Montana 137 Eriogonum pyrolifolium

+ Perianths white to cream or yellow; inflorescences subtended by 3-10 or more bracts; flowerings stem weakly erect or erect to ascending; widespread (19)

19 (18) Perianths white to cream; e Arizona, Colorado, sw Kansas, New Mexico, w Texas 128 Eriogonum jamesii

+ Perianths pale to bright yellow; n Arizona and Colorado n to Alaska and Canada (20)

20 (19) Inflorescences capitate or subcapitate to umbellate or, if compound-umbellate, plants of e Utah, Colorado, and nw New Mexico; plants matted, often cespitose, perennials usually shorter than 3 dm; Colorado Plateau, Rocky Mountains, and n Great Plains from n Arizona and New Mexico to Alaska and Canada (21)

+ Inflorescences compound-umbellate; plants not matted, taller than 3 dm or, if 1.5-3 dm, then plants of n Texas; se New Mexico, n Texas, nw Virginia, and e West Virginia (23)

21 (20) Achenes glabrous; perianths pale yellow; sw Alberta and nw Montana 134 Eriogonum androsaceum

+ Achenes sparsely pubescent on beak; perianths yellow; widespread (22)

22 (21) Inflorescences compound-umbellate or, if umbellate or capitate, not of distribution of E. flavum; Colorado Plateau, s Rocky Mountains and w edge of Great Plains from s Wyoming to n Arizona and n New Mexico 129 Eriogonum arcuatum

+ Inflorescences subcapitate or umbellate; n Great Plains and n Rocky Mountains, Wyoming and Nebraska north to Canada and Alaska, west to e Oregon and Washington 133. Eriogonum flavum (20)

23 (23) Leaf blades 4-8 cm wide; nw Virginia, e West Virginia. 132 Eriogonum allenii

+ Leaf blades 1-3.5 cm wide; se New Mexico, n Texas (24)

24 (23) Plants 4-5 dm; leaf blades (2.5-)3-6.5 cm; se New Mexico 130 Eriogonum wootonii

+ Plants 1.5-3.5(-4) dm; leaf blades (2-)4-12(-15) cm; n Texas 131 Eriogonum correllii

25 (14) Inflorescences not immediately subtended by bracts; flowering stems seemingly with whorl of bracts near middle (portion below whorl technically is a flowering stem, whereas portion above whorl but below solitary involucre technically is a peduncle); California (26)

+ Inflorescences immediately subtended by whorl of bracts; flowering stems without a whorl of bracts near middle; California, w Nevada, s Oregon, disjunct in Washington (29)

26 (25) Perianths whitish to pinkish or rose-red; leaf blades silky-tomentose and silvery abaxially, 0.1-0.3(-0.4) cm wide; Red Mountain, Mendocino County, California 119 Eriogonum kelloggii

+ Perianths yellow; leaf blades tomentose abaxially, 0.2-2(-3) cm wide; not of Mendocino County, California (27)

27 (26) Flowering stems (0.3-)0.4-0.6 dm; leaf blades 1-2(-3) cm wide; Mt. Eddy and Scott Mountain, Siskiyou and Trinity counties, California 140 Eriogonum alpinum

+ Flowering stems 0.5-3 dm; leaf blades 0.2-0.7(-0.8) cm wide; not of Mt. Eddy and Scott Mountain, Siskiyou and Trinity counties, California (28)

28 (27) Perianths sparsely pubescent abaxially; involucral teeth 5-8, 0.5-1.5 mm; North Coast Ranges, Trinity and Tehama counties, California 112 Eriogonum libertini (in part)

+ Perianths glabrous; involucral teeth 8-10, 1-3 mm; Sierra Nevada, Nevada County to Frenso County, California 116 Eriogonum prattenianum (in part)

29 (25) Perianths chalky white, white to rose, or creamy yellow to pale yellowish; stipelike bases of flowers 0.1-0.4 mm (30)

+ Perianths yellow to brownish or sulphur yellow, ochroleucous, or cream and sometimes suffused with blush of pinkish red to maroon, rarely white; stipelike bases of flowers 0.3-1.5 mm (32)

30 (29) Perianths chalky white; flowers 2.5-3.5 mm; involucres (2-)2.5-3.5(-4) mm; Fresno and Tulare counties, California 124 Eriogonum polypodum

+ Perianths white to rose or creamy yellow to pale yellowish; flowers 5-9 mm; n California, wc Nevada (31)

31 (30) Flowers 5-7 mm; achenes 4.5-6 mm; flowering stems prostrate to decumbent or weakly erect; inflorescences subcapitate to umbellate, infrequently 2-umbellate; n California, sw Oregon, and wc Nevada 138 Eriogonum lobbii (in part)

+ Flowers 7-9 mm; achenes 6-8 mm; flowering stems erect or nearly so; inflorescences 2-umbellate; wc Nevada 139 Eriogonum robustum (in part)

32 (29) Plants dioecious, with morphologically different pistillate and staminate plants in fruit (33)

+ Plants synoecious, without morphologically different plants in fruit (35)

33 (32) Leaf blades glabrate and bright green to olive green adaxially; ne California, wc Nevada, s Oregon, disjunct to Yakima County, Washington 125 Eriogonum marifolium

+ Leaf blades lanate to tomentose on both surfaces, usually not green adaxially; Sierra Nevada or Siskiyou and Trinity mountains, California, Oregon, and Nevada (34)

34 (33) Pistillate inflorescences capitate, umbellate after fertilization; leaf blades oblong to oblong-ovate or spatulate, 0.5-1.5 × 0.3-0.7 cm, tomentose; petioles (0.3-)0.5-1 cm; Sierra Nevada of ec California and wc Nevada 126 Eriogonum incanum

+ Pistillate inflorescences usually persistently capitate, rarely umbellate after fertilization; leaf blades elliptic to ovate, (0.5-)1-2 × 0.5-1.5 cm, lanate; petioles 0.7-3 cm; Siskiyou and Trinity mountains, nw California and sw Oregon 127 Eriogonum diclinum

35 (32) Perianths white, cream, ochroleucous, pale yellow, or rarely yellow; involucres villous (36)

+ Perianths sulphur yellow; involucres tomentose (37)

36 (35) Flowering stems 0.4-4 dm; inflorescences compound-umbellate; perianths cream, pale yellow, or rarely yellow; Sierra Nevada, Placer County to Shasta County, or n Coast Ranges, Shasta and Trinity counties to Siskiyou County, California 114 Eriogonum ursinum

+ Flowering stems 0.2-0.6(-1) dm; inflorescences subcapitate; perianths white to ochroleucous; n Coast Ranges, Sonoma and Lake counties, California 115 Eriogonum nervulosum

37 (35) Inflorescences not immediately subtended by bracts; flowering stems seemingly with a whorl of bracts near middle (portion below whorl is flowering stem, portion above whorl but below solitary involucre is peduncle); flowers 5-8 mm; n Coast Ranges in Trinity and Tehama counties, California 112 riogonum libertini (in part)

+ Inflorescences subtended by a whorl of bracts immediately below umbel or head of several involucres; flowering stems not with a whorl of bracts near middle; flowers 3-6 mm; Del Norte, Siskiyou, Trinity, and Tehama counties, California, n to Curry and Josephine counties, Oregon (38)

38 (37) Leaf blade margins not revolute, blade oblong to obovate, (0.4-)0.8-1.3 cm wide; plants matted; n Coast Ranges, Del Norte, Siskiyou, Trinity, and Tehama counties, California, to Curry and Josephine counties, Oregon 111 Eriogonum ternatum

+ Leaf blade margins revolute, blade narrowly elliptic to narrowly oblong, 0.3-0.6(-0.8) cm wide; plants subshrubs; Trinity and Siskiyou counties, California 113 Eriogonum congdonii