Eriogonum plumatella |
Eriogonum effusum |
|
---|---|---|
flat top buckwheat, yucca buckwheat, yucca wild buckwheat |
spreading buckwheat, spreading wild buckwheat |
|
Habit | Shrubs, erect, not scapose, 3–10(–12) × 3–6(–8) dm, tomentose or glabrous, grayish or greenish. | Shrubs, spreading, not scapose, (1.5–)2–5(–7) × 5–15 dm, grayish- to reddish-brown-tomentose to floccose and gray or, rarely, thinly floccose and greenish. |
Stems | erect, without persistent leaf bases, up to 1/2 or more height of plant; caudex stems absent; aerial flowering stems erect, slender, solid, not fistulose, 0.5–2 dm, tomentose or glabrous. |
spreading to erect, typically without persistent leaf bases, up to 1/2 height of plant; caudex stems absent; aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.3–0.8 dm, floccose or glabrous. |
Leaves | basal and cauline, 1 per node; petiole 0.1–0.5 cm, mostly tomentose; blade oblanceolate, 0.6–1.5 × 0.2–0.3 cm, tomentose on both surfaces, occasionally slightly less so adaxially, margins plane. |
cauline, 1 per node; petiole 0.2–0.7 cm, tomentose to floccose; blade oblanceolate to oblong or obovate, (1–)1.5–3 × (0.2–)0.3–0.7 cm, densely white-tomentose abaxially, white-floccose to glabrate or green and glabrous adaxially, margins plane. |
Inflorescences | cymose, flat-topped and in tiers, 15–40 × 15–40 cm; branches dichotomous, divaricately arranged in a zig-zag pattern, tomentose or glabrous; bracts 3, scalelike, 1–7 mm. |
cymose, 10–30(–40) × 10–40 cm; branches dichotomous, white-floccose to glabrate or subglabrous; bracts 3, scalelike, triangular, 0.5–2(–5) mm. |
Peduncles | absent. |
absent or mostly erect, slender, 0.3–2.5 cm, floccose. |
Involucres | 1 per node, turbinate, 2–2.5 × 1.5–2 mm, glabrous; teeth 5, erect, 0.4–0.6 mm. |
1 per node, turbinate, 1.5–2.5(–3) × 1–2 mm, tomentose to floccose; teeth 5, erect, 0.3–0.6 mm. |
Flowers | 2–2.5 mm; perianth white to pale yellow, glabrous; tepals connate proximal 1/4 dimorphic, those of outer whorl obovate, those of inner whorl oblong; stamens exserted, 2–4 mm; filaments pilose proximally. |
2–4 mm; perianth yellow, glabrous; tepals connate proximal 1/4, essentially monomorphic, elliptic to obovate; stamens mostly exserted, 2–4.5 mm; filaments sparsely pilose proximally. |
Achenes | light brown to brown, 2.5–3 mm, glabrous. |
brown, 2–2.5 mm, glabrous. |
Eriogonum plumatella |
Eriogonum effusum |
|
Phenology | Flowering Apr–Oct. | Flowering Jun–Sep. |
Habitat | Sandy flats, washes, and slopes, mixed grassland, saltbush, blackbrush, and creosote bush communities, oak and pinyon-juniper woodlands | Sandy to rocky slopes and flats, mixed grassland and sagebrush communities, juniper and montane conifer woodlands |
Elevation | 400-1700 m (1300-5600 ft) | 1200-2500 m (3900-8200 ft) |
Distribution |
AZ; CA; NV
|
CO; MT; NE; NM; SD; WY
|
Discussion | Eriogonum plumatella is encountered infrequently, primarily on the Mojave Desert, where it occurs in two forms, one with pubescent (var. plumatella) and one with glabrous (var. jaegeri) inflorescence branches. As both forms occur occasionally in the same population, the varieties are not considered to be taxonomically significant. Eriogonum plumatella occurs from Kern County, California, south through Los Angeles (including the foothills of the San Gabriel Mountains), San Bernardino, and Riverside counties to eastern San Diego County. To the east the species is found in Clark County, Nevada, and Mohave and western Yavapai counties, Arizona. A single specimen (Palmer s.n., GH) reportedly was gathered in Utah. Repeated efforts to find the plant in Washington County, Utah, have been unsuccessful, and the record is discounted here. This species is the food plant for the rare pallid dotted-blue butterfly (Euphilotes pallescens pallescens). According to M. L. Zigmond (1981), the Kawaiisu pounded the seeds into a powder and made a mush. Given the small size of the achenes, and the paucity of large populations, the task of gathering sufficient seed must have been daunting. In taste, these seeds differ little from other, more common members of wild buckwheat, so it is likely that achenes of several species were gathered and processed into a watery meal. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eriogonum effusum is rather common on the northern Great Plains and along the eastern slope of the Rocky Mountains in central and eastern Colorado, southeastern Montana, western Nebraska, northern New Mexico, southwestern South Dakota, and southeastern Wyoming. Some specimens from Chaffee County, Colorado, are thinly floccose and greenish (Atwood & Welsh 29689, BRY) and thus similar to E. leptocladon. A collection from Pyramid Lake, Washoe County, Nevada (Frandsen & Brown 182, NESH) is clearly mislabeled. A roadside collection of E. effusum gathered near Little America, Sweetwater County, Wyoming, in 1961 (G. Mason 4025, ASU) was an introduction that has not persisted. The spreading wild buckwheat is occasionally merged with Eriogonum microthecum even though the two are morphologically distinct and their ranges do not overlap. Plants in New Mexico are sometimes difficult to distinguish from the related E. leptocladon var. ramosissimum. The species is the food plant for the Rita dotted-blue butterfly (Euphilotes rita). A hybrid between Eriogonum effusum and E. pauciflorum has been named E. ×nebraskense Rydberg [E. multiceps Nees subsp. nebraskense (Rydberg) S. Stokes; E. pauciflorum Pursh var. nebraskense (Rydberg) Reveal]. The hybrid is known from Weld County, Colorado; Cheyenne and Kimball counties, Nebraska; and Converse and Platte counties, Wyoming. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 308. | FNA vol. 5, p. 248. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla |
Sibling taxa | ||
Synonyms | E. plumatella var. jaegeri | E. microthecum var. effusum |
Name authority | Durand & Hilgard: J. Acad. Nat. Sci. Philadelphia, n. s. 3: 45. (1855) | Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 15. (1848) |
Web links |