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chinchweed, common chinchweed, manybristle chinchweed

Rusby's chinchweed, Rusby's cinchweed

Habit Annuals, 1–30 cm (often forming rounded bushes); herbage spicy-scented. Annuals, 5–50 cm (taprooted); herbage spicy-scented.
Stems

ascending, glabrous or puberulent.

erect or ascending, glabrous or sparsely puberulent (in decurrent lines).

Leaves

linear, 10–60 × 1–2 mm, margins with 1–3 pairs of setae, faces glabrous (dotted on margins with round to oval oil-glands 0.3–0.5 mm).

linear to narrowly elliptic, 10–50 × 1–5 mm, margins with 1–3 pairs of setae, faces glabrous or sparsely puberulent (dotted on margins with round oil-glands 0.2–0.7 mm).

Peduncles

3–40 mm.

20–80 mm.

Involucres

campanulate to cylindric.

campanulate.

Ray florets

(7–)8(–10);

corollas 3–8 mm.

8(–13);

corollas 5–11 mm.

Disc florets

6–34;

corollas 2–5.5 mm (weakly 2-lipped, glabrous or glandular-puberulent).

(7–)20–55;

corollas 3.5–5 mm (2-lipped).

Phyllaries

distinct, linear, 3–8 × 0.5–1.7 mm (dotted with 1–5 subterminal oil-glands plus 2–5 pairs of submarginal oil-glands).

distinct, oblong or narrowly obovate, 4–7 × 1–2 mm (dotted with 0–2, subterminal oil-glands plus 2–4 pairs of inconspicuous, round to narrowly elliptic, submarginal oil-glands).

Heads

in congested or open, cymiform arrays.

borne singly or in open, cymiform arrays.

Cypselae

2–5.5 mm, strigillose to short-pilose (hair tips curled, bulbous);

ray pappi usually coroniform, rarely of 1+ awns or bristles 1–4 mm;

disc pappi usually of 16–24, subplumose bristles 1.5–4 mm, rarely coroniform.

3–4.5 mm, strigillose or short-pilose;

ray pappi of 1–4, antrorsely barbed awns 1–4 mm or coroniform;

disc pappi of 15–30, antrorsely barbed bristles 2.5–5 mm or coroniform.

2n

= 24 (as P. palmeri).

Pectis papposa

Pectis rusbyi

Phenology Flowering Jul–Oct.
Habitat Deserts, desert grasslands, arid scrub, dry woodlands
Elevation 600–1600 m (2000–5200 ft)
Distribution
from FNA
AZ; CA; NM; NV; TX; UT; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Mexico (Baja California Sur, Sinaloa, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

Pectis papposa generally flowers following summer monsoon rains in the desert of southwestern United States and northern Mexico. In favorable years, it becomes an aspect dominant, coloring wide areas of the desert with its bright yellow heads.

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

Pectis rusbyi is much less common in Arizona than P. papposa var. papposa, with which it sometimes grows.

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

Key
1. Phyllaries 3–5 mm; disc florets 6–14(–18); disc pappi 1–2.5 mm
var. papposa
1. Phyllaries 5–8 mm; disc florets 12–24(–34); disc pappi 2.5–4 mm
var. grandis
Source FNA vol. 21, p. 227. FNA vol. 21, p. 227.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis
Sibling taxa
P. angustifolia, P. cylindrica, P. filipes, P. glaucescens, P. humifusa, P. imberbis, P. linearifolia, P. linifolia, P. longipes, P. prostrata, P. rusbyi, P. ×floridana
P. angustifolia, P. cylindrica, P. filipes, P. glaucescens, P. humifusa, P. imberbis, P. linearifolia, P. linifolia, P. longipes, P. papposa, P. prostrata, P. ×floridana
Subordinate taxa
P. papposa var. grandis, P. papposa var. papposa
Synonyms P. palmeri
Name authority Harvey & A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 62. (1849) Greene ex A. Gray: in A. Gray et al., Syn. Fl. N. Amer. 1(2): 361. (1884)
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