Pectis prostrata |
Pectis ×floridana |
|
---|---|---|
spreading chinchweed, spreading cinchweed |
chinchweed |
|
Habit | Annuals, 1–30 cm (across); herbage not scented. | Annuals, 5–30 cm; herbage spicy-scented. |
Stems | prostrate to ascending (often mat-forming, densely leafy, especially distally), puberulent (in lines or throughout). |
decumbent to erect, glabrous. |
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, 15–35 × 1–2 mm, margins with 3–5 pairs of setae, faces glabrous (abaxial densely dotted with round oil-glands ca. 0.2 mm). |
Peduncles | 1–2 mm. |
5–25 mm. |
Involucres | campanulate, cylindric, or ellipsoid. |
cylindric to narrowly fusiform. |
Ray florets | 5; corollas 2.5–3.5 mm (scarcely surpassing phyllaries). |
5; corollas 3.5–4.2 mm. |
Disc florets | 3–17; corollas 1.8–2.5 mm (2-lipped). |
4–6; corollas 2.2–2.5 mm (2-lipped). |
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). |
coherent (falling together), linear or linear-oblanceolate, 5–7 × 1–2 mm (dotted with scattered, oval oil-glands 0.2–0.3 mm). |
Heads | borne singly or in congested, (leafy) cymiform arrays. |
borne singly or in condensed, cymiform arrays. |
Cypselae | 2.5–4.5 mm, strigillose; pappi of 2 (ray) or 5 (disc) lanceolate scales 1.5–2.5 mm. |
3–3.5 mm (pericarps darkening, not swelling, ovules abortive), strigillose to short-pilose; pappi of 2 (ray) or 5 (disc) slender, antrorsely scabrid, aristate scales 2–2.5 mm, sometimes with additional shorter scales or bristles. |
2n | = 24. |
= 3x = 36. |
Pectis prostrata |
Pectis ×floridana |
|
Phenology | Flowering Jul–Nov. | Flowering Sep–Dec. |
Habitat | Open sites in deserts, grasslands, oak-pine-juniper woodlands, roadsides | Roadsides |
Elevation | 0–2000 m (0–6600 ft) | 0–50 m (0–200 ft) |
Distribution |
AZ; FL; LA; NM; TX; Mexico; Central America; West Indies
|
FL |
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.) |
Pectis ×floridana is a triploid hybrid between P. glaucescens (2n = 48) and P. prostrata (2n = 24). The hybrids have been observed where the parental taxa grow together in roadside habitats in southern Florida. At the type locality, the hybrids were nearly as common as the parentals. Meiosis in the hybrids is very irregular; resulting pollen grains are malformed and variable in size and apparently all sterile. No fruits have been observed. Regeneration of the hybrids from season to season apparently requires new hybridization events. The hybrids superficially resemble Pectis linearifolia from which they differ in having spicy-scented rather than lemon-scented herbage, longer peduncles, and strongly carinate phyllaries that cohere at the bases and fall together as a group. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 21, p. 224. | FNA vol. 21, p. 226. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis | Asteraceae > tribe Heliantheae > subtribe Pectidinae > Pectis |
Sibling taxa | ||
Name authority | Cavanilles: Icon. 4: 12, plate 324. (1797) | D. J. Keil: Sida 11: 389. (1986) |
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