Portulaca halimoides |
Portulacaceae |
|||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
desert portulaca, purslane, silkcotton purslane |
purslane family |
|||||||||||||||||||||||||||||||||||||||||
Habit | Plants annual; roots fibrous. | Subshrubs [shrubs] or herbs, annual, biennial, or perennial, often succulent or fleshy. | ||||||||||||||||||||||||||||||||||||||||
Stems | prostrate to suberect, often pinkish, succulent; trichomes conspicuous at nodes and in inflorescence; branches to 3–20(–25) cm. |
|||||||||||||||||||||||||||||||||||||||||
Leaves | blades linear to oblong-linear, terete to hemispheric, 2–14(–20) × 0.4–2(–3) mm, apex obtuse to acute; involucrelike leaves 4–8. |
opposite, subopposite, or alternate and sometimes secund, sometimes rosulate or subrosulate, exstipulate (except Portulaca and Talinopsis, with nodal or axillary hairs regarded as stipular); blade margins mostly entire, occasionally dentate to crisped. |
||||||||||||||||||||||||||||||||||||||||
Inflorescences | axillary or terminal, cymose, racemose, paniculate, or umbellate, sometimes glomerate, spikelike, or with flowers solitary, open to congested. |
|||||||||||||||||||||||||||||||||||||||||
Flowers | 3–8 mm diam.; petals yellow, obovate, 2–4 × 1–2.5 mm; stamens 4–18; stigmas 3–4(–5). |
mostly radially symmetric, sometimes slightly irregular (in Montia); sepals 2–9; petals (1–)2–19 or sometimes absent, distinct or connate basally; stamens 1–many, opposite and sometimes basally adnate to petals; gynoecium 2–9-carpelled; ovary 1, superior (half-inferior to inferior in Portulaca), 1-locular throughout or initially plurilocular and becoming 1-locular distally (in Portulaca), placentation basal or free-central, ovules 1-many; style present, sometimes branched, or absent; stigmas 1–9. |
||||||||||||||||||||||||||||||||||||||||
Fruits | capsular. |
|||||||||||||||||||||||||||||||||||||||||
Capsules | ovoid, 1.1–2 mm diam. |
|||||||||||||||||||||||||||||||||||||||||
Seeds | gray or leaden, 0.3–0.5(–0.6) mm diam.; lateral surfaces with densely arranged, flattened, stellate cells, tubercles absent; usually with a smooth, occasionally papillose, spine abaxially. |
smooth or sculptured, with or without strophioles or elaiosomes. |
||||||||||||||||||||||||||||||||||||||||
x | = 4–9, 11, 13, 15, 23. |
|||||||||||||||||||||||||||||||||||||||||
2n | = 18. |
|||||||||||||||||||||||||||||||||||||||||
Portulaca halimoides |
Portulacaceae |
|||||||||||||||||||||||||||||||||||||||||
Phenology | Flowering late spring–early fall. | |||||||||||||||||||||||||||||||||||||||||
Habitat | Dry soil, sand dunes, arroyos | |||||||||||||||||||||||||||||||||||||||||
Elevation | 900-2300 m (3000-7500 ft) | |||||||||||||||||||||||||||||||||||||||||
Distribution |
AZ; CA; CO; NM; NV; OK; TX; UT; Central America; South America; West Indies
|
Primarily Southern Hemisphere; poorly represented in Eurasia |
||||||||||||||||||||||||||||||||||||||||
Discussion | Young plants of Portulaca halimoides in desert areas may exhibit reddish stems and sepals. As the yellow petals fade, the persistent, reddish sepals cover the top of the capsule, giving the false impression of red flowers. Immature seeds are reddish brown to brownish black and may be papillose. Morphologic variability occurs in relation to habitat differences over the range of this species. Desert conditions produce depauperate plants; more robust specimens occur in Central America and South America. The type of P. halimoides is conspecific with P. parvula A. Gray within this context. A. Gray (1887) cited P. halimoides from the Florida Keys; that is unconfirmed and is likely a confusion with P. rubricaulis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 20–30, species ca. 500 (9 genera, 91 species in the flora). The eastern New World species of Portulacaceae seem to have a closer relationship with the African species, and the western New World species a closer one with the Australian species, than the two New World groups have with each other to each other. The outer perianth segments, referred to herein as sepals, are held by some (e.g., T. Eckardt 1976) to be modified bracteoles, the petals then representing the true sepals. However, the traditional interpretation, adopted here and in most North American floras, still finds current support (R. C. Carolin 1987). A comparable situation prevails with respect to the cauline leaves in Claytonia and other genera, which are widely interpreted to be foliaceous bracts (R. C. Carolin 1987); here again, as is appropriate in a descriptive context, the traditional terminology is employed. In Talinopsis and Portulaca, the stipular nature of the nodal or axillary hairs also has been a matter of discussion. The question was revisited by R. Geesink (1969), who denied their stipular origin. The relationships of the family are not a matter of dispute (A. Cronquist 1981; R. C. Carolin 1987); the same cannot be said for the relationships and delimitations of the genera, which have always been labile. They are, at present, the subject of active research, which has led to the current acceptance of Phemeranthus and Cistanthe. Changes in the generic classification are discussed in the treatments of the genera concerned. Because of the uncertain relationships, the genera and species are listed alphabetically. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||||||||||||||||||||||||||||||
Key |
|
|||||||||||||||||||||||||||||||||||||||||
Source | FNA vol. 4, p. 499. | FNA vol. 4, p. 457. | ||||||||||||||||||||||||||||||||||||||||
Parent taxa | Portulacaceae > Portulaca | |||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||
Synonyms | P. parvula | |||||||||||||||||||||||||||||||||||||||||
Name authority | Linnaeus: Sp. Pl. ed. 2, 1: 639. (1762) | Adanson | ||||||||||||||||||||||||||||||||||||||||
Web links |
|