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Thomas eriogonum, Thomas' buckwheat, Thomas' wild buckwheat

corymbed wild buckwheat, crispleaf buckwheat, crispleaf wild buckwheat, white wild buckwheat

Habit Herbs, spreading, annual, 0.5–3 dm, glabrous, greenish, sometimes grayish or reddish. Shrubs or subshrubs, spreading, rounded, occasionally erect, rarely somewhat matted, not scapose, (0.5–)1.5–8(–15) × (2–)3–15(–23) dm, grayish- to reddish-brown-tomentose to floccose or glabrous, grayish or greenish.
Stems

caudex absent;

aerial flowering stems erect, solid, not fistulose, 0.2–1 dm, glabrous except for few glands proximally.

spreading or erect, often with persistent leaf bases, up to 3/4 or more height of plant;

caudex stems absent or somewhat matted;

aerial flowering stems erect or nearly so, slender or occasionally stout, solid, not fistulose, (0.1–)1–2 dm, tomentose to floccose, occasionally glabrous.

Leaves

basal;

petiole 0.5–3 cm;

blade round to round-reniform, 0.5–2 × 0.5–2 cm, densely white-tomentose abaxially, floccose to glabrate and greenish adaxially, margins plane.

cauline, 1 per node;

petiole 0.1–1.5 cm, tomentose to floccose;

blade lanceolate to oblanceolate or elliptic to nearly orbiculate, rarely cordate, (0.5–)1–3(–4.5) × (0.3–)0.5–3(–3.5) cm, densely white-, tannish- or brownish-tomentose on both surfaces or less so to nearly glabrous and green adaxially, margins occasionally crenulate.

Inflorescences

cymose, open to diffuse, 5–25 × 5–25 cm;

branches glabrous;

bracts 3, scalelike, 1–2.5 × 1–2 mm.

cymose, rarely capitate or umbellate, diffuse to rather open, (1–)3–20 × 2–25(–30) cm;

branches dichotomous, tomentose, floccose, or rarely glabrous;

bracts 3, scalelike, usually triangular, and 1–3(–6) mm, or leaflike, 10–25 mm, and similar to leaf blades.

Peduncles

capillary, spreading to slightly recurved, straight or curved, capillary, 0.5–3 cm, glabrous.

absent.

Involucres

turbinate-campanulate, 0.6–1.2 × 0.7–1.3 mm, glabrous;

teeth 5, erect, 0.4–0.6 mm.

1 per node, turbinate, (1–)1.5–3.5 × 1–2(–2.5) mm;

teeth 5, erect, 0.3–1 mm.

Flowers

0.8–1 mm in early anthesis, becoming 1.2–2 mm;

perianth yellow in early anthesis, becoming white to rose, short-hispidulous;

tepals dimorphic, those of outer whorl cordate, becoming saccate-dilated proximally, those of inner whorl spatulate;

stamens included, 0.5–0.9 mm;

filaments mostly glabrous.

(1.5–)2–3.5 mm;

perianth white to cream, pink, or pale yellow to yellow, glabrous or rarely sparsely pilose;

tepals connate proximal 1/4–1/3, essentially monomorphic, oblanceolate to spatulate;

stamens included to slightly exserted, 1–4(–5) mm;

filaments typically pilose proximally.

Achenes

brown to dark brown, usually lenticular, 0.8–1 mm, glabrous.

brown, 2–2.5(–3) mm, glabrous except for occasional papillate beak.

2n

= 40.

Eriogonum thomasii

Eriogonum corymbosum

Phenology Flowering year-round.
Habitat Sandy flats, washes, and slopes, saltbush, greasewood, creosote bush, and sagebrush communities, pinyon and/or juniper woodlands
Elevation -70-1200(-1400) m (-200-3900(-4600) ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; NM; NV; TX; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Eriogonum thomasii is common to abundant and even weedy throughout its range on the Mojave and Sonoran deserts in Arizona, southeastern California, southern Nevada, and southwestern Utah. The distinctive swollen bases of the outer tepals are easy to observe in fruiting material but not always obvious in early anthesis.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 8 (8 in the flora).

Eriogonum corymbosum is a difficult complex of overlapping expressions, some of which are maintained here as taxonomically significant. Although perianth color is used to group the varieties, this feature is not consistent even in single populations. Therefore, population trends in perianth color must be noted in the field. Most of the varieties are then distinguished on the basis of leaf characters, and again, considerable variation can be seen in some populations. Still, the combination of flower color, leaf features, and geographic distribution should prove useful in distinguishing the varieties.

S. L. Welsh et al. (2003) alluded to hybrid combinations involving Eriogonum corymbosum and other species. Aside from the instances involving E. brevicaule, discussed below, none has been confirmed. Most of the putative hybrids are misidentified specimens of E. lonchophyllum or collections of var. corymbosum in which the leaf-margins are not decidedly crisped, a feature usually seen only in fully mature plants.

Eriogonum corymbosum was widely used by Native Americans. P. A. Vestal (1940) reported that the Hopi pressed boiled stalks into cakes that, when dried, were eaten with salt. J. W. Fewkes (1896) indicated that boiled leaves were mixed with cornmeal and water, and then baked into a kind of bread. S. A. Weber and P. D. Seaman (1985) indicated that A. F. Whiting was aware of a decoction of leaves (probably from var. glutinosum) being used for headaches. Variety glutinosum also was used primarily to treat tuberculosis, or at least as a cough medicine (D. E. Moerman 1986).

Some of the expressions of Eriogonum corymbosum are attracting the interest of gardeners, a few are coming into cultivation, and several selections are now being developed. The plants are slow growing but can be transplanted with some degree of success. Members of the varieties are food plants for Ellis’s dotted-blue butterfly (Euphilotes ellisi).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Perianths usually pale yellow to yellow, occasionally white; s Utah, n Arizona, se Nevada
→ 2
1. Perianths white to cream or pink; sw Wyoming s through e Utah and w Colorado to nw New Mexico and Arizona
→ 4
2. Inflorescence branches glabrous or nearly so; sw Utah
var. aureum
2. Inflorescence branches tomentose to floccose
→ 3
3. Leaf blades greenish-floccose adaxially; Colorado Plateau, n Arizona, s Utah
var. glutinosum
3. Leaf blades silvery-floccose adaxially; Mojave Desert, se Nevada, sc Utah
var. nilesii
4. Leaf blades elliptic-oblong to nearly orbiculate, 1-3(-3.5) × 1-2.5(-3.5) cm
→ 5
4. Leaf blades lanceolate to oblanceolate or elliptic, (0.5-)1-3(-4.5) × (0.3-)0.5-1.5 cm
→ 6
5. Leaf blades elliptic-oblong to oblong or ovate, rarely cordate, densely white- to tan-lanate or less so to brownish-floccose adaxially; plants brownish-white- tomentose; flowers 2-2.5(-3) mm
var. velutinum
5. Leaf blades usually broadly ovate to nearly orbiculate, densely grayish-tomentose abaxially, sometimes tomentose to floccose on both surfaces, or more often subglabrous or glabrous and green adaxially; plants greenish-tomentose; flowers 2.5-3 mm
var. orbiculatum
6. Plants sprawling subshrubs, 0.5-1.5 dm, occasionally shrubs, 2-4.5 dm; leaf blades 0.5-2 × 0.3-0.6(-0.8) cm; subalpine in bristlecone pine communities
var. heilii
6. Plants erect subshrubs or shrubs, 3-10 dm; leaf blades 1-3(-4.5) × (0.3-)0.5-1.5 cm; desert scrub to montane forest communities
→ 7
7. Leaves cauline 2 or more length of flowering stems; n Arizona, w Colorado, e and s Utah, sw Wyoming
var. corymbosum
7. Leaves cauline 4 or less length of flowering stems; c and e Utah
var. revealianum
Source FNA vol. 5, p. 404. FNA vol. 5, p. 255.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla
Sibling taxa
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
Subordinate taxa
E. corymbosum var. aureum, E. corymbosum var. corymbosum, E. corymbosum var. glutinosum, E. corymbosum var. heilii, E. corymbosum var. nilesii, E. corymbosum var. orbiculatum, E. corymbosum var. revealianum, E. corymbosum var. velutinum
Synonyms E. effusum subsp. corymbosum
Name authority Torrey: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 17. (1856)
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