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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
from FNA
AZ; NM; TX; Mexico (Baja California Sur, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Mexico (Chihuahua, Sonora)
[BONAP county map]
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
P. angustifolia, P. filipes, P. glaucescens, P. humifusa, P. imberbis, P. linearifolia, P. linifolia, P. longipes, P. papposa, P. prostrata, P. rusbyi, P. ×floridana
P. angustifolia, P. cylindrica, P. filipes, P. glaucescens, P. humifusa, P. linearifolia, P. linifolia, P. longipes, P. papposa, P. prostrata, P. rusbyi, P. ×floridana
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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