Flora of North America species comparison

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Eriogonum thomasii

Eriogonum cernuum

Thomas eriogonum, Thomas' buckwheat, Thomas' wild buckwheat

nodding buckwheat, nodding wild buckwheat
Habit Herbs, spreading, annual, 0.5–3 dm, glabrous, greenish, sometimes grayish or reddish. Herbs, spreading to erect, annual, 0.5–6 dm, glabrous, grayish, greenish or reddish.
Stems

caudex absent;

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

caudex absent;

aerial flowering stems erect, solid, not fistulose, 0.3–2 dm, 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.

basal or sheathing up stems 2–10 cm;

petiole 1–4 cm, tomentose;

blade round-ovate to orbiculate, (0.5–)1–2(–2.5) × (0.5–)1–2(–2.5) cm, white- to grayish-tomentose abaxially, tomentose to floccose or glabrate and grayish or greenish adaxially, margins plane.
Inflorescences

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

branches glabrous;

bracts 3, scalelike, 1–2.5 × 1–2 mm.

cymose, open to diffuse, 5–50 × 5–40 cm;

branches glabrous;

bracts 3, scalelike, 1–2 × 1–2.5 mm.
Peduncles

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

spreading to ascending or deflexed to cernuous, infrequently absent, straight or curved, slender, 0.1–2.5 cm, glabrous.
Involucres

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

teeth 5, erect, 0.4–0.6 mm.

turbinate, (1–)1.5–2 × 1–1.5 mm, glabrous;

teeth 5, erect, 0.4–0.7 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.

1–2 mm, glabrous;

perianth white to pinkish, becoming rose to red;

tepals dimorphic, those of outer whorl pandurate, those of inner whorl obovate;

stamens mostly exserted, 1–2 mm;

filaments pilose proximally.
Achenes

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

light brown to brown, 3-gonous, 1.5–2 mm, glabrous.
2n

= 40.

Eriogonum thomasii

Eriogonum cernuum
Phenology Flowering year-round. Flowering Apr–Oct.
Habitat Sandy flats, washes, and slopes, saltbush, greasewood, creosote bush, and sagebrush communities, pinyon and/or juniper woodlands Sandy to gravelly or clayey flats and slopes, mixed grassland, saltbush, sagebrush, and mountain mahogany communities, oak, pinyon-juniper, and conifer woodlands
Elevation -70-1200(-1400) m (-200-3900(-4600) ft) 600-3100(-3300) m (2000-10200(-10800) ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; NE; NM; NV; OR; SD; UT; WA; WY; AB; SK
[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.)

Eriogonum cernuum is widely distributed, being infrequent to common or even abundant and weedy. It is common throughout most of its range in southeastern Oregon, eastern California, southern Idaho, Nevada, Utah, northern Arizona, and New Mexico. The species is rare in southeastern Washington (Franklin County). It is less common and more widely scattered in Colorado, Wyoming, and Montana, and on the northern Great Plains in southern Alberta and Saskatchewan, western South Dakota, and western Nebraska. The northern Great Basin phase, with sessile involucres, has been called var. viminale, but this difference now appears to be ecologic rather than genetic.

Seeds of the nodding wild buckwheat were gathered by the Navajo (Diné) people, pounded into a meal, and eaten dry or made into a porridge (P. A. Vestal 1952; L. C. Wyman and S. K. Harris 1951).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 5, p. 404. FNA vol. 5, p. 401.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma
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. 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. 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
Synonyms E. cernuum var. psammophilum, E. cernuum subsp. tenue, E. cernuum var. tenue, E. cernuum var. umbraticum, E. cernuum subsp. viminale, E. cernuum var. viminale
Name authority Torrey: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 14. (1848)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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