font settings

Font Size: Large | Normal | Small
Font Face: Verdana | Geneva | Georgia

Boerhavia

(Genus)

Overview

[ Back to top ]

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 procumbent, decumbent, ascending, or erect, unarmed, with or without glutinous bands on internodes. Leaves petiolate, pairs unequal in size in each pair; blade thin or thick and slightly fleshy, base symmetric to asymmetric. Inflorescences 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. Flowers 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. Fruits 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.

Species ca. 40: warm-temperate and tropical regions worldwide.

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. Standleys 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).


[1]

Taxonomy

[ Back to top ]

The Genus Boerhavia is further organized into finer groupings including:

Bibliography

[ Back to top ]

Footnotes

[ Back to top ]
  1. Richard W. Spellenberg "Boerhavia". in Flora of North America Vol. 4 Page 14, 15, 17, 1. Oxford University Press. Online at EFloras.org.

Sources

[ Back to top ]
Last Revised: August 24, 2012
2012/08/24 17:24:09