Pectis cylindrica |
Pectis imberbis |
|
---|---|---|
Sonoran chinchweed, Sonoran cinchweed, Sonoran lemonweed, three-ray chinchweed |
beardless chinchweed, tall chinchweed |
|
Habit | Annuals, 1–20 cm (across or high); herbage not scented. | Perennials, 30–120 cm (caudices woody, 2–8+ mm diam.); herbage unscented. |
Stems | prostrate to ascending (often mat-forming, densely leafy distally), puberulent (in decurrent lines or throughout) or glabrate. |
erect, glabrous. |
Leaves | (bluish green) linear to linear-oblanceolate or narrowly oblong, 10–30 × 1.5–4 mm, margins with 2–5 pairs of setae 1–2 mm, faces glabrous (abaxial densely dotted with scattered, circular oil-glands 0.05–0.2 mm). |
narrowly linear, 10–50 × 1–2 mm (sometimes smaller, bractlike distally), margins with 0–1 pairs of setae, faces glabrous (abaxial dotted near each margin with a row of elliptic oil-glands ca. 0.3 mm). |
Peduncles | 1–5 mm. |
10–80 mm. |
Involucres | cylindric. |
cylindric. |
Ray florets | 3(–4); corollas 3–4 mm (scarcely surpassing phyllaries). |
5; corollas 6–11 mm (laminae often dotted near margins with inconspicuous oil-glands). |
Disc florets | (3–)7–14; corollas 2.2–2.6 mm (2-lipped). |
4–7; corollas 3.7–6 mm (lobes 5, equal, each with 1 subterminal oil-gland). |
Phyllaries | coherent (falling together), oblong to oblong-obovate, 6–10 × 2–3 mm (dotted with scattered, elliptic oil-glands 0.05–0.15 mm). |
distinct, linear-oblong, 5–9.5 × 1–1.5 mm (each dotted with 1–2 swollen, subapical oil-glands and a row of 2–3 linear, submarginal oil-glands on each side of midrib). |
Heads | borne singly or in congested, (leafy) cymiform arrays. |
borne singly or in open, cymiform arrays. |
Cypselae | 4–5.5 mm, puberulent (distally glandular-puberulent); pappi of 2 (ray) and 5 (disc) lanceolate scales 1.5–3.5 mm. |
3.5–5 mm, puberulent (hair tips blunt); pappi of 1–3 stout awns 1–2 mm or coroniform. |
2n | = 48. |
= 24. |
Pectis cylindrica |
Pectis imberbis |
|
Phenology | Flowering Jul–Nov. | Flowering Aug–Oct. |
Habitat | Deserts, oak-juniper woodlands, grasslands, wash channels, mud flats, lawns, roadsides | Pine-oak-juniper woodlands, grasslands, arid shrublands |
Elevation | 700–1500 m (2300–4900 ft) | 1000–1700 m (3300–5600 ft) |
Distribution |
AZ; NM; TX; Mexico (Baja California Sur, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Sonora)
|
AZ; Mexico (Chihuahua, Sonora) |
Discussion | Pectis cylindrica (2n = 48) is similar to P. prostrata (2n = 24); the two occasionally grow together (D. J. Keil 1975b). Some herbaria contain mixed collections of the two. No evidence is available of hybrids between the two. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Pectis imberbis occurs in relatively small, widely separated populations. Overgrazing may be a factor in the scarcity of these plants. They are generally more than 25 cm before they begin to flower and may be unable to reproduce under grazing pressure. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 21, p. 225. | FNA vol. 21, p. 229. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis |
Sibling taxa | ||
Synonyms | P. prostrata var. cylindrica | |
Name authority | (Fernald) Rydberg: in N. L. Britton et al., N. Amer. Fl. 34: 198. (1916) | A. Gray: Smithsonian Contr. Knowl. 5(6): 70. (1853) |
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