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spreading chinchweed, spreading cinchweed

chinchweed, common chinchweed, manybristle chinchweed

Habit Annuals, 1–30 cm (across); herbage not scented. Annuals, 1–30 cm (often forming rounded bushes); herbage spicy-scented.
Stems

prostrate to ascending (often mat-forming, densely leafy, especially distally), puberulent (in lines or throughout).

ascending, glabrous or puberulent.

Leaves

linear to narrowly oblanceolate, 10–40 × 1.5–7 mm, margins with 4–12 pairs of setae 1–3 mm, faces glabrous (abaxial densely dotted with round oil-glands 0.1–0.3 mm).

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).

Peduncles

1–2 mm.

3–40 mm.

Involucres

campanulate, cylindric, or ellipsoid.

campanulate to cylindric.

Ray florets

5;

corollas 2.5–3.5 mm (scarcely surpassing phyllaries).

(7–)8(–10);

corollas 3–8 mm.

Disc florets

3–17;

corollas 1.8–2.5 mm (2-lipped).

6–34;

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

Phyllaries

coherent (falling together), oblong to obovate, 5–8 × 1–3 mm (often dotted in submarginal rows and sometimes along midribs with elliptic oil-glands 0.1–0.3 mm).

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

Heads

borne singly or in congested, (leafy) cymiform arrays.

in congested or open, cymiform arrays.

Cypselae

2.5–4.5 mm, strigillose;

pappi of 2 (ray) or 5 (disc) lanceolate scales 1.5–2.5 mm.

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.

2n

= 24.

Pectis prostrata

Pectis papposa

Phenology Flowering Jul–Nov.
Habitat Open sites in deserts, grasslands, oak-pine-juniper woodlands, roadsides
Elevation 0–2000 m (0–6600 ft)
Distribution
from FNA
AZ; FL; LA; NM; TX; Mexico; Central America; West Indies
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; NV; TX; UT; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

The development of roads and highways has created ideal habitats for Pectis prostrata. Its range appears to be expanding along the coasts of Florida; it was discovered in Louisiana relatively recently. It can be expected to spread along the Gulf Coast and perhaps northward along the Atlantic Coast as well. Autogamy has apparently assisted P. prostrata to spread rapidly as suitable new habitats have become available.

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

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.)

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. 224. 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. papposa, P. rusbyi, P. ×floridana
P. angustifolia, P. cylindrica, P. filipes, P. glaucescens, P. humifusa, P. imberbis, P. linearifolia, P. linifolia, P. longipes, P. prostrata, P. rusbyi, P. ×floridana
Subordinate taxa
P. papposa var. grandis, P. papposa var. papposa
Name authority Cavanilles: Icon. 4: 12, plate 324. (1797) Harvey & A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 62. (1849)
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