Flora of North America species comparison

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Eriogonum microthecum

Eriogonum heermannii

slender buckwheat, slender wild buckwheat

Heerman buckwheat, Heermann's buckwheat, Heermann's 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. Shrubs and subshrubs, spreading to rounded and occasionally erect, not scapose, (0.5–)1–20 × 2–25 dm, glabrous or occasionally floccose, sometimes scabrellous, greenish, infrequently 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.

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

caudex stems absent;

aerial flowering stems erect or nearly so, slender to stout, solid, not fistulose, 0.02–0.5 dm, thinly tomentose or glabrous.
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.

cauline, 1 per node, quickly deciduous;

petiole 0.1–1.5 cm, floccose or glabrous;

blade linear, oblanceolate or spatulate or elliptic, or oblong, (0.4–)1–2(–4) × 0.1–0.8 cm, tomentose to floccose or glabrous abaxially, floccose to thinly floccose or glabrous adaxially, margins plane.
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.

cymose or racemose, 1–25(–30) × 1–30(–35) cm;

branches dichotomous, sometimes with secondaries suppressed, smooth or angled to ridged and grooved, glabrous or occasionally floccose or scabrous;

bracts 3, scalelike, 0.3–2 mm.
Peduncles

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

absent.
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.

1 per node, narrowly turbinate or campanulate, 0.7–3 × 0.7–4 mm, glabrous, infrequently floccose;

teeth 5, erect, 0.3–0.7 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.

(1.5–)2–4 mm;

perianth white, yellowish white, pink, or reddish, glabrous;

tepals connate proximal 1/4, dimorphic, those of outer whorl obovate to orbiculate, those of inner whorl narrowly lanceolate to oblong;

stamens exserted, 2–5 mm;

filaments pilose proximally.
Achenes

brown, 1.5–3 mm, glabrous.

light brown to brown, 2–5 mm, glabrous.

Eriogonum microthecum

Eriogonum heermannii
Distribution
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; UT
[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.)

Varieties 8 (8 in the flora).

As Eriogonum heermannii is here circumscribed, the number of varieties is dramatically decreased from past presentations, with E. apachense reduced to synonymy under a now greatly expanded var. argense. Also included in that variety is the more stoutly branched var. subracemosum. The southern var. heermannii of basically desert ranges and the more northern var. occidentale of the Coast Ranges in California are maintained, but their separation is more traditional than certain. The fragile and bulky nature of many dried, often poorly prepared specimens, and the tendency for leaves to fall away have made varietal identification within E. heermannii difficult.

Eriogonum heermannii varieties are food plants for Ellis’s dotted-blue butterfly (Euphilotes ellisi) and the Mormon metalmark (Apodemia mormo mormo).

(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
1. Flowering stems and inflorescence branches round or angled, scabrellous or papillate-scabrous; plants often densely branched
→ 2
1. Flowering stems and inflorescence branches round, not angled, usually smooth, glabrous or thinly tomentose; plants sparsely branched
→ 3
2. Flowering stems and inflorescence branches round, usually distinctly scabrellous or infrequently papillate-scabrous; Arizona, se California, Nevada
var. argense
2. Flowering stems and inflorescence branches sharply ridged and deeply grooved, minutely scabrellous; nw Arizona, se California, s Nevada, sw Utah
var. sulcatum
3. Involucres not racemosely arranged on inflorescence branches, or only last 2-3 so disposed; inflorescences diffusely branched, glabrous; Great Basin or northeast edge of Mojave Desert
→ 4
3. Involucres racemosely arranged along inflorescence branches or at least at tips of branches; inflorescences openly branched, glabrous or floccose to thinly tomentose; Mojave and Sonoran deserts
→ 5
4. Inflorescence branches mostly slender, smooth, not ridged, not spinose; inflorescences 3-15(-23) × 5-20 cm; subshrubs or shrubs, 3-7 × 5-12(-15) dm; Great Basin, ec California and Nevada
var. humilius
4. Inflorescence branches stoutish, faintly ridged and grooved, spinose; inflorescences 3-7(-10) × 3-10(-12) cm; shrubs, 1-3 × 1.5-5(-8) dm; Mojave Desert, sw Utah and nw Arizona
var. subspinosum
5. Inflorescence branches thinly tomentose to floccose; s California, s Nevada, nw Arizona
var. floccosum
5. Inflorescence branches glabrous; s Nevada, California
→ 6
6. Involucres racemosely arranged; inflorescence branches whiplike; s Nevada
var. clokeyi
6. Involucres racemosely arranged only distally; inflorescence branches not whiplike; California
→ 7
7. Leaf blades 0.5-1.5 cm, glabrous abaxially; inflorescence branches stout; sc California
var. heermannii
7. Leaf blades 1.5-3(-4) cm, mostly tomentose to floccose abaxially (at least in early anthesis); inflorescence branches slender; sw California
var. occidentale
Source FNA vol. 5, p. 242. FNA vol. 5, p. 304.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla 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. 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. 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. 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
E. heermannii var. argense, E. heermannii var. clokeyi, E. heermannii var. floccosum, E. heermannii var. heermannii, E. heermannii var. humilius, E. heermannii var. occidentale, E. heermannii var. subspinosum, E. heermannii var. sulcatum
Synonyms E. geniculatum
Name authority Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) Durand & Hilgard: in War Department [U.S.], Pacif. Railr. Rep. 5(3): 14. (1857)
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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