Eriogonum divaricatum |
Eriogonum inflatum |
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divergent buckwheat, divergent wild buckwheat |
bottle stopper, desert trumpet, Indian pipeweed |
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Habit | Herbs, spreading, 1–2(–3) dm, puberulent to short-pilose, greenish to reddish. | Herbs, erect, perennial, occasionally flowering first year, 1–10(–15) dm, glabrous, usually glaucous, grayish. |
Stems | aerial flowering stems decumbent to spreading, 0.3–0.5 dm, puberulent to short-pilose. |
caudex compact; aerial flowering stems erect, solid or hollow and fistulose, (0.2–)2–5 dm, glabrous, usually glaucous, occasionally hirsute proximally. |
Leaves | basal and cauline; basal: petiole 1–4(–5) cm, puberulent to short-pilose, blade elliptic-oblong to orbiculate, 1–2(–2.5) × 1–2(–2.5) cm, puberulent to short-pilose and green on both surfaces; cauline: petiole (0–)0.1–2 cm, puberulent to short-pilose, absent distally, blades opposite, oblanceolate to oblong or elliptic, 0.3–1(–1.5) × 0.2–0.8(–1.2) cm, similar to basal blade. |
basal; petiole 2–6 cm, hirsute; blade oblong-ovate to oblong or rounded to reniform, (0.5–)1–2.5(–3) × (0.5–)1–2(–2.5) cm, short-hirsute and grayish or greenish on both surfaces, sometimes less so or glabrous and green adaxially, margins occasionally undulate. |
Inflorescences | cymose, distally uniparous due to suppression of secondary branches, diffuse, 5–25 × 10–45 cm; branches puberulent; bracts 1–3(–5) × 1–2 mm. |
cymose, open, spreading to erect, 5–70 × 5–50 cm; branches occasionally fistulose, glabrous, usually glaucous; bracts 3, scalelike, 1–2.5(–5) × 1–2.5 mm. |
Peduncles | absent. |
erect, straight, filiform to capillary, 0.5–2(–3.5) cm, glabrous. |
Involucres | somewhat appressed to branches, campanulate, 1–2 × 1–2 mm, pilose; teeth 5, lobelike, spreading to somewhat reflexed, 0.7–1.5 mm. |
turbinate, 1–1.5 × 1–1.8 mm, glabrous; teeth 5, erect, 0.4–0.6 mm. |
Flowers | (1–)1.5–2 mm; perianth yellow, rarely pale yellow, hispidulous and glandular with yellowish-white hairs; tepals monomorphic, oblong-lanceolate to oblong-ovate; stamens included, 0.7–1.5 mm; filaments pilose proximally. |
(1–)2–3(–4) mm; perianth yellow with greenish or reddish midribs, densely hirsute with coarse curved hairs; tepals monomorphic, narrowly ovoid to ovate; stamens exserted, 1.3–2.5 mm; filaments glabrous or sparsely pubescent proximally. |
Achenes | light brown, 3-gonous, 1.5–2 mm. |
light brown to brown, lenticular to 3-gonous, 2–2.5 mm, glabrous. |
2n | = 32. |
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Eriogonum divaricatum |
Eriogonum inflatum |
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Phenology | Flowering May–Oct. | Flowering year-round. |
Habitat | Heavy clay flats and slopes, saltbush, greasewood, and sagebrush communities, pinyon-juniper woodlands | Sandy to gravelly washes, flats, and slopes, mixed grassland, saltbush, creosote bush, mesquite, and sagebrush communities, pinyon and/or juniper woodlands |
Elevation | 1100-2300(-2500) m (3600-7500(-8200) ft) | -30-1800(-2000) m (-100-5900(-6600) ft) |
Distribution |
AZ; CO; NM; UT; WY
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AZ; CA; CO; NM; NV; UT; Mexico (Baja California, Sonora)
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Discussion | Eriogonum divaricatum basically is a species of the Colorado Plateau of southwestern Wyoming (Sublette, Sweetwater, and Uinta counties), eastern Utah (Carbon, Emery, Garfield, Grand, Kane, San Juan, Sevier, and Wayne counties), western Colorado (Mesa and Montezuma counties), northern Arizona (Apache, Coconino, and Navajo counties), and northwestern New Mexico (McKinley and San Juan counties), where it is infrequent to common but only rarely abundant. There are several disjunct populations well removed from that core area; the species occurs in Beaver and Millard counties of west-central Utah, and in Clayhole Valley, Mohave County, Arizona. In New Mexico, it was found around San Ysidro, Sandoval County, in 1926. The most extreme disjunctions were two populations found in Argentina during the growing season of 1899–1900. Those plants were named Eriogonum ameghinoi Spegazzini, which ultimately became the only species of the genus Sanmartinia M. Buchinger. Probably introduced there by migrating birds, the species did not persist in South America (J. L. Reveal 1981b). The divergent wild buckwheat was used ceremonially by the Navajo (Diné) people in one of their snake dances, and portions of the plant were smoked in the treatment of snakebite (A. Clifford, pers. comm.; L. C. Wyman and S. K. Harris 1951). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The cause of the fistulose stem and inflorescence branches in Eriogonum inflatum was imaginatively attributed by A. M. Stone and C. T. Mason (1979) to the larvae of gall insects. This fallacy continues to appear in the literature. Greenhouse studies have shown that stems of this and some other species of the genus inflate without the presence of any insects. Other researchers have shown that the inflation involves a build-up of CO2 within the stems, which take over as the primary photosynthetic body as leaves wilt or eventually dry up and fall away from the plant (C. D. Osmond et al. 1987). Not all individuals of E. inflatum will have fistulose stems and branches, as this feature is partly a function of available moisture: the drier the conditions, the less pronounced the inflation. Stems produced in the summer tend to be inflated less frequently than those produced in the spring. The “annual” phase of Eriogonum inflatum is distinct from its truly annual relatives. Its flowering stems and inflorescence branches are distinctly grayish, whereas those of the true annuals are green or yellowish green. As circumscribed here, Eriogonum inflatum occurs in Arizona, southern and east-central California, western Colorado, northwestern New Mexico, central and southern Nevada, and southern and eastern Utah. Some Native Americans occasionally ate newly emerged stems of Eriogonum inflatum (S. A. Weber and P. D. Seaman 1985; M. L. Zigmond 1981). The hollow stems were used as drinking tubes (Weber and Seaman) and pipes (E. W. Gifford 1936). This wild buckwheat is a food plant for the desert metalmark butterfly (Apodemia mormo deserti). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 429. | FNA vol. 5, p. 386. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma |
Sibling taxa | ||
Synonyms | E. glaucum, E. inflatum var. deflatum, E. trichopes subsp. glaucum | |
Name authority | Hooker: Hooker’s J. Bot. Kew Gard. Misc. 5: 265. (1853) | Torrey & Frémont: in J. C. Frémont, Rep. Exped. Rocky Mts., 317. (1845) |
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