Flora of North America species comparison

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Eriogonum microthecum

Eriogonum annuum

slender buckwheat, slender wild buckwheat

annual buckwheat, annual wild buckwheat
Habit Subshrubs or shrubs, erect to spreading, not scapose, 0.2–1.5 × (0.6–)1–13(–16) dm, white- to tannish-tomentose, floccose, or glabrous. Herbs, 5–20 × 5–10 dm, grayish.
Stems

spreading to erect, typically without persistent leaf bases, up to 1/2 height of plant;

caudex stems absent or spreading;

aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.05–1.5 dm, lanate, tomentose, floccose, subglabrous, or glabrous.

Aerial flowering stems

slender, 4–10(–15) dm, floccose to densely tomentose.
Leaves

cauline, 1 per node or fasciculate;

petiole 0.1–0.5 cm, tomentose to floccose or glabrous;

blade usually elliptic, sometimes linear to obovate, 0.3–3.5 × (0.07–)0.1–1.2 cm, tomentose abaxially, less so or glabrous adaxially, margins occasionally revolute.

petiole (rosette) 0.3–1.2 cm, or petiole (cauline) 0.2–0.5 cm, tomentose to floccose;

blade oblanceolate to oblong, 1–7 × 0.3–1.5 cm, densely tomentose abaxially, floccose adaxially not thickened and auriculate-subclasping proximally;

margins entire or slightly revolute.
Inflorescences

cymose, compact, often flat-topped, 0.5–6(–12) × 1–10(–13) cm;

branches dichotomous, whitish-lanate to brownish- or reddish-tomentose to floccose or glabrate, infrequently green or gray and subglabrous or glabrous;

bracts 3, scalelike, linear to triangular, 1–5 mm.

3–10 × 2–7 cm;

bracts triangular, 1–4 mm.
Peduncles

absent or mostly erect, slender, 0.3–1.5 cm, tomentose to floccose.

0.1–0.5 cm, tomentose to floccose.
Involucres

1 per node, turbinate, (1.5–)2–3.5(–4) × 1.3–2.5(–3) mm, tomentose, floccose, subglabrous, or glabrous;

teeth 5, erect, (0.3–)0.5–1(–1.7) mm.

turbinate to campanulate, 2.5–4 × 2–3 mm, tomentose to floccose abaxially, glabrous adaxially;

teeth 5–6, 0.4–1 mm.
Flowers

1.5–3(–4) mm;

perianth yellow or white to pink, orange, rose, red, or occasionally cream, glabrous;

tepals connate proximal 1/5–2/5, essentially monomorphic, oblong to obovate;

stamens usually exserted, 2.5–4 mm;

filaments sparsely to densely puberulent proximally.

1–2.5 mm;

perianth white or cream to rose;

tepals: those of outer whorl obovate, 1–2 × 0.9–1.5 mm, those of inner whorl narrowly ovate to oblong, 1.5–4 × 1.2–1.8 mm;

stamens usually included, 1–2 mm.
Achenes

brown, 1.5–3 mm, glabrous.

1.5–2 mm.
2n

= 40.

Eriogonum microthecum

Eriogonum annuum
Phenology Flowering Apr–Nov.
Habitat Sandy flats, slopes, dunes, and banks, mixed grassland, oak and conifer woodlands
Elevation (0-)100-1900(-2300) m ((0-)300-6200(-7500) ft)
Distribution
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; KS; MT; ND; NE; NM; OK; SD; TX; WY; Mexico (Chihuahua)
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 13 (13 in the flora).

Eriogonum microthecum is used as browse by deer and to a lesser degree by cattle and sheep. Some forms are now in cultivation. The species is reportedly used by the Piute of Nevada in the treatment of tuberculosis, lameness, rheumatism, and bladder trouble (P. Train et al. 1941). S. A. Weber and P. D. Seaman (1985) stated that A. F. Whiting found the plants being used as a tea by the Havasupai in northern Arizona. Members of E. microthecum are food plants for subspecies of the rare pallid blue butterfly (Euphilotes pallescens). Also found on this species is the cythera metalmark (Apodemia mormo cythera). Some authors have referred E. effusum to this species, even though the ranges of the two species do not overlap and intermediates are unknown.

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

Eriogonum annuum is widespread and common to locally abundant or even weedy on the Great Plains of the central United States and extreme north-central Mexico. It was collected in Sherburne County, Minnesota, in 1982, but that population did not persist. The species was recently found as an introduction at Sandy Hook in Monmouth County, New Jersey (Snyder & McArthur s.n., NY), but its fate there remains to be determined. Unfortunately, this weedy species recently has been introduced into northern Arizona as a roadside wild flower. C. L. Perez et al. (1998) have demonstrated that the seed bank can be rich in seeds of this species, but germination rates are low.

The Lakota people traditionally used the annual wild buckwheat as an aid in the treatment of sore mouths in children, seemingly in association with teething (D. J. Rogers 1980). Leaves were used to stain buffalo and deer hides by the Kiowa (P. A. Vestal and R. E. Schultes 1939). Vestal (1952) stated that the species was considered a “life medicine” by the Navajo (Diné) people; it was used also for protection against witches. It is likely that E. annuum was obtained by the Navajo through trade, but it might have been grown locally in historic times where the species recently has been reintroduced.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Perianths yellow
→ 2
1. Perianths various shades of white, cream, orange, pink, or red, not yellow
→ 4
2. Flowering stems and inflorescence branches usually glabrous; e Oregon and wc Idaho
var. microthecum
2. Flowering stems and inflorescence branches tomentose to floccose; se Oregon and sw Idaho s to e California and w Nevada
→ 3
3. Leaf blades (0.2-)0.3-0.6(-0.8) cm wide; flowers (1.5-)2-2.5(-3) mm; involucres 2-2.5 mm; achenes 1.5-2 mm; se Oregon and sw Idaho s to e California and w Nevada
var. ambiguum
3. Leaf blades 0.5-1.2 cm wide; flowers 2.5-3 mm; involucres 2.5-4 mm; achenes 2.5-3 mm; ne California, nw Nevada
var. schoolcraftii
4. Tomentum whitish (see also var. alpinum of the Sierra Nevada, California); flowering stems and inflorescence branches infrequently glabrous
→ 5
4. Tomentum brownish or reddish (may be white in var. alpinum), or flowering stems and inflorescence branches essentially glabrous
→ 6
5. Leaf margins not revolute; flowering inflorescence branches floccose or glabrous; northern phase of species
var. laxiflorum
5. Leaf margins revolute or nearly so; flowering inflorescence branches lanate to tomentose, or if subglabrous or glabrous, then southern phase of species
var. simpsonii
6. Plants shrubs, 3-6 dm
→ 7
6. Plants subshrubs, 0.2-1.5(-2) dm
→ 8
7. Flowering stems and inflorescence branches tomentose when young, becoming floccose at maturity; flowers 1.5-2(-2.5) mm; achenes 1.8-2 mm; Death Valley region, California
var. panamintense
7. Flowering stems and inflorescence branches lanate to tomentose at maturity; flowers 2-2.5(-3) mm; achenes 2.5-3 mm; Transverse Ranges, California
E. microthecumvar. corymbosoides
8. Leaf blades elliptic or ovate, margins not revolute; flowers (1.5-)2-3.5(-4) mm
→ 9
8. Leaf blades linear or linear-oblanceolate to narrowly elliptic, margins often revolute; flowers 1.5-2.5 mm
→ 10
9. Leaf blades 0.5-1 × (0.2-)0.3-0.5(-0.6) cm; involucres (2-)2.5-3 mm; flowers (2.5-)3-3.5(-4) mm; San Gabriel Mountains, California
var. johnstonii
9. Leaf blades 0.3-0.7(-0.8) × 0.1-0.4 cm; involucres 2.5-3.5 mm; flowers (1.5-)2-3.5 mm; desert ranges of se California, c Nevada, and Utah1f. Eriogonum microthecum var. lapidicola [8. Shifted to left margin—Ed.]
→ 8
10. Involucres 3-4 mm; perianths cream; San Bernardino Mountains, California
var. lacus-ursi
10. Involucres (1.5-)2-3 mm; perianths white, pink, red, or rose; Sierra Nevada of California, or e Nevada and w Utah
→ 11
11. Flowering stems glabrous; leaf blades sparsely floccose or glabrous adaxially; desert ranges, se Nevada
var. arceuthinum
11. Flowering stems white- to brownish-floccose to subglabrous, or reddish-tomentose to floccose; leaf blades floccose to subglabrous adaxially; California or wc Utah
→ 12
12. Tomentum white to brownish; Sierra Nevada, California
var. alpinum
12. Tomentum reddish; desert ranges, wc Utah
var. phoeniceum
Source FNA vol. 5, p. 242. FNA vol. 5.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Micrantha
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. 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
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, 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. 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. microthecum var. alpinum, E. microthecum var. ambiguum, E. microthecum var. arceuthinum, E. microthecum var. johnstonii, E. microthecum var. lacus-ursi, E. microthecum var. laxiflorum, E. microthecum var. microthecum, E. microthecum var. panamintense, E. microthecum var. phoeniceum, E. microthecum var. schoolcraftii, E. microthecum var. simpsonii, E. microthecumvar. corymbosoides
Synonyms E. annuum subsp. cymosum, E. annuum subsp. hitchcockii
Name authority Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) Nuttall: Trans. Amer. Philos. Soc., n. s. 5: 164. (1835)
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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