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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 5—Alberta, Colorado, Montana, and Wyoming

1 Plants shrubs or subshrubs   (2)
+ Plants herbs   (15)
2 (1) Leaf blades oblanceolate to lanceolate or elliptic, cordate to nearly orbiculate, apices rounded or nearly so   (3)
+ Leaf blades linear to narrowly elliptic or narrowly lanceolate, apices sharply acute or nearly so   (5)
3 (2) Flowering stems and inflorescence glabrous, rarely tomentose   23 Eriogonum lonchophyllum (in part)
+ Flowering stems and inflorescence tomentose to floccose, glabrate, or subglabrous   (4)
4 (3) Inflorescences 10-30(-40) × 10-40 cm, floccose to glabrate or subglabrous; e Colorado   2 Eriogonum effusum (in part)
+ Inflorescences (1-)3-20 × 2-25(-30) cm, tomentose to floccose; w Colorado   16 Eriogonum corymbosum (in part)
5 (2) Leaf margins plane or merely rolled   (6)
+ Leaf margins usually revolute   (9)
6 (5) Leaf blades (0.5-)1-3 cm; widespread   (7)
+ Leaf blades 3-6 cm; Colorado, sw Wyoming   (8)
7 (6) Leaf blades usually elliptic, (0.5-)1-2(-2.5) × (0.1-)0.2-0.6(-0.8) cm, densely to sparsely white-tomentose abaxially, less so to sparsely white-floccose adaxially; nw Colorado, sw Wyoming and sw Montana   1 Eriogonum microthecum (in part)
+ Leaf blades oblanceolate to oblong or obovate, (1-)1.5-3 × (0.2-)0.3-0.7 cm, densely white-tomentose abaxially, white-floccose to glabrate or green and glabrous adaxially; e Colorado, w Nebraska and se Wyoming to se Montana and sw South Dakota   2 Eriogonum effusum (in part)
8 (6) Flowering stems and inflorescence branches tomentose to floccose   16 Eriogonum corymbosum (in part)
+ Flowering stems and inflorescence branches glabrous; Colorado   23 Eriogonum lonchophyllum (in part)
9 (5) Leaf blades 1.5-4(-6) cm   (10)
+ Leaf blades 0.5-1.8(-2.5) cm   (12)
10 (9) Flowering stems and inflorescence branches tomentose to floccose;Montezuma County, Colorado   4 Eriogonum leptocladon
+ Flowering stems and inflorescence branches glabrous or thinly pubescent; widespread   (11)
11 (10) Leaf blades linear to linear-oblanceolate, (0.03-)0.1-0.3 cm wide, greenish adaxially; inflorescences green and compactly branched; Montezuma County, Colorado   7 Eriogonum leptophyllum
+ Leaf blades narrowly lanceolate or oblanceolate to elliptic, 0.2-2 cm wide, grayish; inflorescences mostly grayish and openly branched; widespread   23 Eriogonum lonchophyllum (in part)
12 (9) Tepals monomorphic   (13)
+ Tepals dimorphic   (14)
13 (12) Leaf blades usually narrowly elliptic, 0.5-1.8(-2.5) cm, mostly white-floccose adaxially, margins slightly revolute; tepals connate proximal 1/ 4; widespread   1 Eriogonum microthecum (in part)
+ Leaf blades oblanceolate, 0.5-1.2(-1.5) cm, subglabrous or glabrous and green adaxially, margins tightly revolute; tepals connate proximal 1/ 2; Delta and Montrose counties, Colorado   9 Eriogonum pelinophilum
14 (12) Flowers (2.5-)3-3.5 mm; leaf blades oblanceolate, thinly grayish-pubescent or glabrous and greenish adaxially, margins tightly revo- lute; plants 1-2.5 dm; Montezuma County, Colorado   8 Eriogonum clavellatum
+ Flowers 2.5-4(-4.5) mm; leaf blades linear-oblanceolate to narrowly elliptic, reddish- or tannish-tomentose adaxially, margins revolute; plants 0.2-0.8 dm; Mesa County, Colorado   10 Eriogonum bicolor
15 (1) Perianths pubescent   (16)
+ Perianths glabrous   (21)
16 (15) Achenes villous to tomentose   (17)
+ Achenes glabrous   (18)
17 (16) Plants matted, 0.3-0.7 dm; w Colorado   68 Eriogonum shockleyi
+ Plants erect, not matted, 1-3.5 dm; e Colorado   69 Eriogonum lachnogynum
18 (16) Perianths yellow; e Montana, ne Wyoming   27 Eriogonum brevicaule (in part)
+ Perianths white to rose; widespread   (19)
19 (18) Perianths pustulose; involucres campanulate, not rigid; Big Horn County, Wyoming, and Carbon County, Montana   50 Eriogonum mancum (in part)
+ Perianths not pustulose; involucres turbinate or campanulate, rigid; widespread   (20)
20 (19) Involucres narrowly turbinate; leaf blades 1-4 cm; Great Plains   64 Eriogonum pauciflorum (in part)
+ Involucres campanulate; leaf blades 0.3-0.4 cm; nw Colorado   66 Eriogonum tumulosum
21 (15) Tepals dimorphic   (22)
+ Tepals usually monomorphic   (23)
22 (21) Inflorescences compoundly branched   96 Eriogonum strictum
+ Inflorescences capitate or umbellate   98 Eriogonum ovalifolium
23 (21) Inflorescences virgate or racemose, branches bearing 5-20(-30) racemosely arranged involucres; leaf blades (1.5-)2-6(-10) cm, elliptic to ovate or oval to nearly rotund; Colorado   78 Eriogonum racemosum
+ Inflorescences umbellate to cymose or capitate or if racemose, plants forming dense, compact mats; leaf blades 0.5-1.5 cm or, if longer, linear to oblanceolate, 3-10 cm, or spatulate to elliptic, (0.3-)1.5-4 cm; widespread. [24. Shifted to left margin.—Ed.]   (24)
24 (23) Plants erect to spreading, not forming mats   (25)
+ Plants forming mats   (30)
25 (24) Inflorescences capitate or umbellate-cymose; c Colorado   31 Eriogonum brandegeei
+ Inflorescences cymose; n or w Colorado northward   (26)
26 (25) Leaf blades densely white-tomentose on both surfaces, elliptic; nw Colorado   40 Eriogonum batemanii
+ Leaf blades tomentose abaxially, thinly floccose and greenish or glabrous and green adaxially, linear to elliptic, lanceolate, or spatulate; n Colorado north   (27)
27 (26) Leaf blades linear to oblanceolate or spatulate, (1-)1.5-10 × 0.1-0.9(-1.2) cm, margins not revolute; widespread   27 Eriogonum brevicaule (in part)
+ Leaf blades usually linear to lanceolate, rarely narrowly elliptic, (0.5-)1-3(-4) × 0.1-0.2(-0.5) cm, margins often revolute; nw Colorado   (28)
28 (27) Peduncles absent; to be expected in Moffat County, Colorado   28 Eriogonum viridulum
+ Peduncles erect, 0.2-1.5 cm; Colorado   (29)
29 (28) Leaf blades linear to narrowly lanceolate, margins revolute; perianths yellow; flowering stems and inflorescence branches floccose to nearly glabrous; Garfield and Mesa counties, Colorado   33 Eriogonum contortum
+ Leaf blades lanceolate, margins plane; perianths ochroleucous or pale yellow or rarely yellow; flowering stems and inflorescence branches glabrous; Rio Blanco County, Colorado   29 Eriogonum ephedroides
30 (24) Perianths usually yellow   (31)
+ Perianths white to ochroleucous or rose   (32)
31 (30) Scapes and involucres glandular; w Montana   49 Eriogonum crosbyae
+ Scapes and involucres not glandular; sw Wyoming, nw Colorado   27 Eriogonum brevicaule (in part)
32 (30) Perianths pustulose; leaf blades 0.4-1.5 cm; involucres tomentose; Montana, ne Wyoming   (33)
+ Perianths not pustulose; leaf blades 1-6 cm; involucres usually glabrous except for hairs on teeth; widespread   (34)
33 (32) Involucres 2-5 per cluster, not rigid; flowering stem scapelike, inflorescence bracts 3-5; peduncles absent   50 Eriogonum mancum (in part)
+ Involucres 1 per node, rigid; flowering stems and inflorescence bracts absent; peduncles present   51 Eriogonum soliceps
34 (32) Peduncles 0.1-0.4 cm; inflorescences cymose-umbellate; flowering stems glabrous or floccose to tomentose; leaf blades linear to linear-oblanceolate, (2-)3-6 × 0.1-0.3 cm; nc Colorado and se Wyoming   25 Eriogonum exilifolium
+ Peduncles absent; inflorescences capitate or subcapitate to cymose-umbellate; flowering stems glabrous or tomentose; leaf blades linear-oblanceolate to oblanceolate to lanceolate or narrowly spatulate to elliptic, 1-4(-5) × 0.1-1 cm; Great Plains or Rocky Mountains   (35)
35 (34) Flowering stems glabrous; Rocky Mountains, Colorado, above 2800 m   24 Eriogonum coloradense
+ Flowering stems tomentose; Great Plains, Montana to Colorado, below 1800 m   64 Eriogonum pauciflorum (in part)

List of Keys


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