Boerhavia diffusa |
Boerhavia |
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red spiderling, spreading hogweed |
spiderling |
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Habit | Herbs, perennial [rarely appearing annual], sometimes slightly woody at base; taproot fusiform, woody. | Herbs, annual or perennial, sometimes suffrutescent at base, slender, often glandular, glabrous, or pubescent, from slender and soft or stout, ± woody, and ropelike or fusiform taproot. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | decumbent, ascending, or erect, usually profusely branched throughout, 3–10 dm, glabrous or minutely pubescent basally, glabrous or sparsely pubescent distally. |
procumbent, decumbent, ascending, or erect, unarmed, with or without glutinous bands on internodes. |
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Leaves | mostly in basal 1/2 of plant; larger leaves with petiole 10–30 mm, blade broadly lanceolate, ovate, or broadly ovate, occasionally ± round, 20–60 × 15–50 mm (distal leaves smaller, often proportionally narrower), base truncate, broadly cuneate, round, or shallowly cordate, often oblique, margins sinuate, apex obtuse to round, abaxial surface paler than adaxial, glabrous or minutely puberulent, sometimes glandular, usually with few large multicellular hairs on veins, adaxial surface glabrous, rarely sparsely puberulent, neither surface punctate. |
petiolate, pairs unequal in size in each pair; blade thin or thick and slightly fleshy, base symmetric to asymmetric. |
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Inflorescences | terminal, forked ca. 3–6 times ± equally, diffuse, occasionally with sticky internodal bands; branches divergent, terminating in compact subumbellate or capitate, 2–5-flowered clusters. |
terminal and axillary, pedunculate or not clearly pedunculate because of repeated branching from distal axils, diffuse, and then usually widely cymose, paniculate, or thyrsiform, terminal portions cymose, racemose, spicate, subumbellate, umbellate, subcapitate, or capitate, rarely borne singly; bracts ± persistent and not accrescent, or deciduous, 1–3 beneath each flower, distinct, lanceolate, minute, thin, translucent. |
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Flowers | pedicel shorter than 0.5 mm; bract at base of perianth quickly deciduous, 1, lanceolate, 0.8–1 mm; perianth purplish red to reddish pink or nearly white, campanulate beyond constriction, 1–1.5 mm; stamens 2–3, included or barely exserted. |
bisexual, chasmogamous; perianth radially symmetric or slightly bilaterally symmetric, campanulate or widely funnelform, constricted beyond ovaries, tube abruptly expanded to (4–)5-lobed limb; stamens 2–8, included or exserted; styles at or extending beyond anthers; stigmas peltate. |
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Fruits | (1–)2–5(–9) per cluster, gray-brown to brown, obpyramidal, (3–)3.5–4.5 × 1–1.2 mm (l/w: 2.8–4.1), apex broadly conic, with sparse or moderately dense stipitate-glandular hairs on ribs, less densely pubescent or glabrous in sulci [rarely entirely glabrous]; ribs 5, round, smooth; sulci ± 2–2.5 times as wide as base of ribs, not rugose, not papillate. |
fusiform, clavate, oblong-clavate, obovoid, or obpyramidal, stiffly coriaceous; ribs (3–)5, rounded, angular, or winglike, smooth, glabrous or glandular-pubescent; sulci smooth or rugose, epidermal surface smooth, papillate, or minutely pubescent. |
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2n | = 26, 52, 54, 116. |
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Boerhavia diffusa |
Boerhavia |
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Phenology | Flowering mid winter–early fall [year-round]. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Disturbed areas, waste places, roadsides, dry pinelands, among scrub on tropical reefs | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 0-50[-1800] m (0-200[-5900] ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
FL; GA; SC; Mexico; Central America; South America; West Indies; Asia; Africa; Indian Ocean Islands; Pacific Islands; Australia
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Warm-temperate and tropical regions worldwide |
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Discussion | Boerhavia diffusa belongs to a pantropical complex whose distribution, because of differing taxonomic treatments, is not precisely discernable. In North America, the West Indies, and elsewhere, the complex has been treated as having one (e.g., R. W. Long and O. Lakela 1971; R. P. Wunderlin 1998) or two species (E. A. Kellogg 1988; J. K. Small 1913c; P. C. Standley 1918; C. Whitehouse 1996). In the latter situation various binomials have been used. The abrupt bend in the ribs near the fruit apex, making a broadly conic apex, seems to be a useful character for distinguishing most B. diffusa. The shape of the apex, the sparse pubescence of the fruit, the few fruits in individual terminal clusters, and the open, ± leafless inflorescence may have led R. E. Woodson Jr. and H. J. Kidd (1961) to suspect hybridization of this complex with the annual B. erecta. Hybridization is plausible (R. Spellenberg 2000), but clearly intermediate plants are not known. The leaves are sometimes used as a vegetable (C. Whitehouse 1996). Extracts from roots are used to prepare an expectorant, a diuretic, and a laxative, and in treating asthma (S. P. Ambasta 1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 40 (16 in the flora). Numerous authors, particularly those of the eighteenth and nineteenth centuries, “corrected” to Boerhaavia Linneaus’ intentional Latinization (Boerhavia) of Boerhaave’s name. Boerhavia sometimes includes Anulocaulis, Commicarpus, and Cyphomeris (F. R. Fosberg 1978). At the species level, there is variation that is often difficult to treat taxonomically, especially among annuals of the Sonoran Desert and the pantropical B. diffusa–B. coccinea complex. Many species probably are highly autogamous (R. Spellenberg 2000). P. C. Standley’s publications on the family in North America (1909, 1911, 1918) have been the basis for much of the subsequent floristic efforts, with all authors taking a more conservative approach. Nevertheless, careful examination of Boerhavia fruits indicates that some of the entities that Standley proposed represent distinct taxa. For most species in the flora, identification requires mature fruits. In this treatment, the range of ratios of length to width (l/w) of individual fruits of a species is given as a means to relate shape. Fruits from a number of Boerhavia species exude mucilage when wet (J. M. Willson and R. Spellenberg 1977). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 19. | FNA vol. 4, p. 17. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Nyctaginaceae > Boerhavia | Nyctaginaceae | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 3. (1753) | Linnaeus: Sp. Pl. 1: 3. (1753): Gen. Pl. ed. 5, 4. (1754) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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