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

round-leaf wild buckwheat, roundleaf buckwheat

woolly-cup wild buckwheat, woollycup buckwheat

Habit Herbs, spreading, annual, 0.5–4 dm, glabrous and often glaucous, greenish to grayish. Herbs, erect or matted, sometimes scapose, 1–3.5 × 1–2 dm or 0.05–0.2 × 0.5–3.5 dm, floccose or silky-tomentose, grayish.
Stems

caudex absent;

aerial flowering stems erect, solid, not fistulose, 0.1–0.5(–0.7) dm, glabrous.

spreading or matted, occasionally with persistent leaf bases, up to 1/4 or more height of plant;

caudex stems matted;

aerial flowering stems erect or nearly so, slender, solid, not fistulose, 1–2 dm and floccose, or (0.1–)0.02–0.5(–0.65) dm and silky-tomentose.

Leaves

basal;

petiole 1.5–4 cm, floccose;

blade cordate to orbiculate, 1–2(–3) × 1–2.5(–3) cm, densely white-tomentose abaxially, floccose or subglabrous and greenish adaxially, margins plane.

basal, 1 per node or fasciculate in terminal tufts;

petiole 0.1–2.5(–3) cm, tomentose to floccose;

blade lanceolate or oblanceolate to narrowly elliptic, 1–2.5(–3) × 0.3–0.5(–0.8) cm, or 0.4–1.2 × 0.1–0.3(–0.35) cm, densely white- or silvery-tomentose on both surfaces, margins plane.

Inflorescences

cymose, open to diffuse, usually flat-topped, 5–35 × 5–35 cm;

branches glabrous;

bracts 3, scalelike, 1–2.5 × 0.5–2 mm.

capitate, subcapitate, umbellate-cymose, or cymose, 2–20 × 2–20 cm, floccose or, if matted, 0.3–1 × 0.3–1 cm;

branches open and divided 1–3 times, 2–20 cm, floccose or if matted, (0–)0.3–0.85 cm, silky-tomentose;

bracts 3, scalelike, triangular, (0.5–)1–3 mm.

Peduncles

erect, straight, stoutish, 0.3–1.5 cm, glabrous.

absent or erect, slender, 2–15 mm, floccose.

Involucres

turbinate to campanulate, 1–2 × 1.5–2.5 mm, glabrous;

teeth 5, erect, 0.4–0.8 mm.

1 per node or 2–5 per cluster, broadly campanulate, 1.5–4 × (2–)3–6(–8) mm, tomentose;

teeth 5, erect to spreading, 1–1.5 mm.

Flowers

1–2.5 mm;

perianth white to pink with greenish to reddish midribs, becoming rose to red, glabrous;

tepals dimorphic, those of outer whorl flabellate, those of inner whorl lanceolate;

stamens included, 1.2–1.7 mm;

filaments pilose proximally.

2.5–5(–6) mm;

perianth yellow, densely white-pubescent;

tepals connate proximal 1/3, monomorphic, lanceolate to broadly lanceolate;

stamens exserted, 3.5–5 mm;

filaments glabrous.

Achenes

dark brown, 3-gonous, 1.5–2 mm, glabrous.

brown to dark brown, 3–4 mm, villous to tomentose.

2n

= 40.

Eriogonum rotundifolium

Eriogonum lachnogynum

Phenology Flowering May–Oct.
Habitat Sandy to gravelly flats and slopes, mixed grassland, saltbush, creosote bush, and mesquite communities, juniper woodlands
Elevation 600-1800 m (2000-5900 ft)
Distribution
from FNA
AZ; NM; TX; Mexico (Chihuahua, Coahuila)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; KS; NM; OK; TX
[WildflowerSearch map]
[BONAP county map]
Discussion

Eriogonum rotundifolium is the southern counterpart to E. cernuum, being common to abundant and occasionally even weedy. Its overall range, however, is significantly smaller. It occurs in Arizona only in Cochise County, but is found more widely in New Mexico, and is common in the trans-Pecos region of western Texas, with scattered populations in Dimmit, Ector, Foard, and Knox counties outside that region.

A sterile Edwin James specimen gathered in 1820 (NY) supposedly was collected near the Rocky Mountains and may be Eriogonum rotundifolium. Also seen at NY is an unattributed, redistributed collection of this species labeled only “Colorado.” Until better documented material from that state is seen, the species is considered not to be a member of the Colorado flora.

F. A. Elmore (1943) reported that the round-leaf wild buckwheat was used by the Navajo (Diné) people as an emetic. My own consumption of a few seeds, as a self-experiment, produced no particular urge to vomit. Inasmuch as the treatment was taken after swallowing ants, it is difficult to know whether the ants or the seeds were the emetic. G. M. Hocking (1956) reported that the leaves were used for sore throats and the stems were eaten raw (the latter proving in the same self-experiment not to be particularly tasty, leaving a slightly sour aftertaste). Hocking also reported that the roots were used medicinally but mentioned no specific ailment.

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

Varieties 3 (3 in the flora).

The Navajo or Diné people consider Eriogonum lachnogynum to be a “life medicine,” making a concoction of shredded roots for the treatment of internal, and some external, ailments. It is often given for diarrhea.

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

Key
1. Plants erect; inflorescences subcapitate, umbellate-cymose, or cymose; flowering stems 1-2 dm at full anthesis; leaf blades 1-2.5(-3) × 0.3-0.5(-0.8) cm; widespread, not in Arizona
var. lachnogynum
1. Plants cespitose mats; inflorescences capitate; flowering stems 0.01-0.65 dm at full anthesis; leaf blades 0.4-1.2 × 0.1-0.35 cm; Arizona, New Mexico
→ 2
2. Flowering stems 0.1-0.5(-0.65) dm, longer than leaves
var. sarahiae
2. Flowering stems (0.01-)0.02-0.05(-0.12) dm, shorter than or just exceeding leaves
var. colobum
Source FNA vol. 5, p. 402. FNA vol. 5, p. 286.
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. 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. 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. 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. lachnogynum var. colobum, E. lachnogynum var. lachnogynum, E. lachnogynum var. sarahiae
Synonyms E. cernuum subsp. glaucescens, E. cernuum subsp. rotundifolium, E. rotundifolium var. angustius
Name authority Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 21. (1856) Torrey ex Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 8. (1856)
Web links