Pectis longipes |
Pectis rusbyi |
|
---|---|---|
longstalk chinchweed, longstalk cinchweed, mat cinchweed |
Rusby's chinchweed, Rusby's cinchweed |
|
Habit | Perennials, 8–25 cm (rhizomes branched, 1–10 mm diam.); herbage lemon-scented or spicy-scented. | Annuals, 5–50 cm (taprooted); herbage spicy-scented. |
Stems | ascending to erect (very leafy), glabrous. |
erect or ascending, glabrous or sparsely puberulent (in decurrent lines). |
Leaves | linear to linear-oblanceolate, 10–55 × 1–3 mm, margins with 1–4 pairs of setae, faces glabrous (conspicuously dotted on margins with round 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 | (30–)50–160 mm. |
20–80 mm. |
Involucres | campanulate. |
campanulate. |
Ray florets | (8–)13(–15); corollas 8–12 mm. |
8(–13); corollas 5–11 mm. |
Disc florets | 25–50; corollas 4–6 mm (2-lipped). |
(7–)20–55; corollas 3.5–5 mm (2-lipped). |
Phyllaries | distinct, linear, linear-oblanceolate, or linear-elliptic, 5–8 × 0.7–2 mm (dotted with 1–3, swollen, subterminal oil-glands 0.3–0.4 mm plus 1–3 pairs of narrow, 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 | borne singly. |
borne singly or in open, cymiform arrays. |
Cypselae | 2.5–4.5 mm, strigillose (hairs tips acute or blunt); ray pappi of 1–2 awns 3–3.5 mm; disc pappi of 2–30 unequal bristles 3–5 mm. |
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, 48. |
= 24 (as P. palmeri). |
Pectis longipes |
Pectis rusbyi |
|
Phenology | Flowering Apr–Nov. | Flowering Jul–Oct. |
Habitat | Grasslands, oak-juniper-mesquite woodlands | Deserts, desert grasslands, arid scrub, dry woodlands |
Elevation | 900–1700 m (3000–5600 ft) | 600–1600 m (2000–5200 ft) |
Distribution |
AZ; NM; Mexico (Chihuahua, Durango, Sonora)
|
AZ; Mexico (Baja California Sur, Sinaloa, Sonora)
|
Discussion | Pectis longipes has been listed from Texas in floras; I have seen no collections from that state. Pectis longipes comprises two cytological races. Diploid, spicy-scented plants occur throughout the range. In southern Arizona, the diploid race is broadly sympatric but locally allopatric with a tetraploid, lemon-scented race. The tetraploid race is nested within the range of the diploids. The races are easily separable by odor, and although they are very similar morphologically, they can be separated also by statistically significant differences in floral dimensions and pollen size (M. A. Luckow 1983). Based upon those minute differences, the type collection is diploid. Because the races are so similar morphologically and because so many of the specimens of P. longipes in herbaria bear no indication of odor, I chose not to give the cytological races formal recognition. (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.) |
Source | FNA vol. 21, p. 226. | FNA vol. 21, p. 227. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis |
Sibling taxa | ||
Synonyms | P. palmeri | |
Name authority | A. Gray: Smithsonian Contr. Knowl. 5(6): 69. (1853) | Greene ex A. Gray: in A. Gray et al., Syn. Fl. N. Amer. 1(2): 361. (1884) |
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