The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Thomas eriogonum, Thomas' buckwheat, Thomas' wild buckwheat

California buckwheat, California wild buckwheat, eastern Mojave buckwheat, eastern Mojave wild buckwheat

Habit Herbs, spreading, annual, 0.5–3 dm, glabrous, greenish, sometimes grayish or reddish. Shrubs or subshrubs, compact to spreading or rounded and more or less erect, occasionally decumbent, infrequently scapose, (1–)2–15 × 2–25(–30) dm, tomentose to canescent, floccose, or glabrous.
Stems

caudex absent;

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

sprawling or spreading to erect, often with persistent leaf bases, up to 1/2 or more height of plant;

caudex stems absent or matted to spreading;

aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.3–2.5(–3) dm, tomentose, canescent, or 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 or fasciculate;

petiole 0.1–0.3 cm, canescent;

blade linear to linear-oblanceolate or oblanceolate, 0.6–1.5(–1.8) × 0.05–0.4(–0.6) cm, white-tomentose or canescent to subglabrous abaxially, tomentose or canescent and grayish, subglabrous, or glabrous and green adaxially, margins often revolute.

Inflorescences

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

branches glabrous;

bracts 3, scalelike, 1–2.5 × 1–2 mm.

cymose, infrequently cymose-umbellate or capitate, compact to open, occasionally flat-topped, 0.2–20 × 0.2–15 cm;

branches dichotomous, infrequently absent, tomentose to canescent or glabrous;

bracts usually 3, scalelike, triangular, and 1–3 mm, or leaflike, linear to oblanceolate, and 3–10 × 1–3 mm.

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–)3–8 per cluster, turbinate to campanulate, 2–4 × 1.5–3 mm, canescent, pubescent, glabrous, or subglabrous;

teeth 5, erect, 0.3–1.2 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.

2.5–3 mm;

perianth white to pinkish, glabrous or pubescent;

tepals connate proximal 1/4, monomorphic, usually elliptic to obovate;

stamens exserted, 2.5–5 mm;

filaments subglabrous or pubescent proximally.

Achenes

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

light brown to brown, 1.8–2.5 mm, glabrous.

2n

= 40.

Eriogonum thomasii

Eriogonum fasciculatum

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; CA; NV; UT; including nw Mexico
[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 5 (4 in the flora).

Eriogonum fasciculatum is a complex, polyploid series of variants that are generally distinct but often difficult to distinguish morphologically. Variety emphereium Reveal is confined to central Baja California, Mexico. The introduction of Eriogonum fasciculatum as a decorative roadside plant by the California Department of Transportation is resulting in hybrid populations involving E. cinereum. The aggressively weedy and (for Arizona) exotic variety foliosum is rapidly invading the native habitat of var. polifolium. Members of E. fasciculatum are food plants for several butterflies, notably the Bernardino dotted-blue (Euphilotes bernardino), lupine blue (Plebeius lupini), Mormon metalmark (Apodemia mormo), and Behr’s metalmark (A. virgulti). Probably the butterfly most commonly seen with the species is the nut-brown hairstreak (Satyrium saepium), which frequents plants in full flower. Eriogonum fasciculatum is also the most important native source of honey in California.

This widespread species was used extensively by Native Americans for a variety of ailments. Its application for pain and headaches (D. P. Barrows 1900; K. Hedges 1986; E. W. Voegelin 1938) was rather common, as was its general use for diarrhea (Hedges; Voegelin). M. L. Zigmond (1981) reported that the Kawaiisu lined their acorn granaries with leaves of var. proliferum to keep out rain—a daunting challenge given the size of the leaves! L. Hinton (1975) reported the use of a decoction of dried flowers and roots to maintain a healthy heart, and M. C. Stevenson (1915) indicated that a powder derived from the roots was used by the Zuñi to treat wounds, whereas a root decoction was taken for colds and hoarseness. B. R. Bocek (1984) reported that the Costanoan Indians of California used a decoction of the plant to treat unspecified urinary problems. F. H. Elmore (1943) reported the use of a decoction of var. proliferum by the Navajo (Diné) people as an anti-witchcraft medicine.

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

Key
1. Leaves thinly white-tomentose abaxially, glabrous adaxially; perianths and involucres mostly glabrous; plants usually decumbent; primarily coastal 80c. Eriogonum fasciculatum var. fasciculatum
→ 1
1. Leaves, perianths, and involucres pubescent or, if subglabrous, then plants of desert regions; plants erect to rounded; generally inland
→ 2
2. Leaves light yellow-green, subglabrous adaxially; involucres and perianths glabrous or subglabrous
var. flavoviride
2. Leaves dark green or grayish, usually pubescent adaxially; involucres and perianths pubescent
→ 3
3. Inflorescences capitate to cymose-umbellate, rarely cymose; leaves canescent on both surfaces or densely tomentose abaxially and canescent adaxially; leaf margins plane or infrequently revolute; mainly deserts
var. polifolium
3. Inflorescences open and mostly cymose; leaves densely white-tomentose abaxially, less so to green and floccose adaxially; leaf margins usually tightly revolute; mainly inner coastal foothills
var. foliolosum
Source FNA vol. 5, p. 404. FNA vol. 5, p. 297.
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. 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. 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. fasciculatum var. flavoviride, E. fasciculatum var. foliolosum, E. fasciculatum var. polifolium
Name authority Torrey: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) Bentham: Trans. Linn. Soc. London 17: 411. (1836)
Web links