Polygala

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Polygala
Polygala vulgaris
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Polygalaceae
Genus: Polygala
L.
Species

See text.

Polygala is a large genus of flowering plants belonging to the family Polygalaceae. They are commonly known as milkworts or snakeroots. The genus is distributed widely throughout much of the world[1] in temperate zones and the tropics.[2] The genus name Polygala comes from the ancient Greek "much milk", as the plant was thought to increase milk yields in cattle.[3]

Description[edit]

Polygala includes annual and perennial plants, shrubs, vines, and trees.[1] The roots often have a scent reminiscent of wintergreen.[2] The leaf blades are generally undivided and smooth-edged, and are alternately arranged in most species. The inflorescence is a raceme or spikelike array of several flowers; the occasional species bears solitary flowers.[2] The flower is bilateral in shape, with two large petal-like sepals on the sides, often called the "wings",[2] and three smaller sepals behind. There are three petals in shades of reddish purple, yellow, or white, which are joined at the bases. The lower of the three is the keel petal, which is "boat-shaped, cucullate [hood-like], or helmet-shaped".[1] The keel petal may have a beak or a fringe on the tip.[2] Stamens and style are within the curve of the keel petal. The fruit is a capsule, sometimes winged. It contains 2 seeds[1] which are usually black, hairy, and tipped with a large white aril.[2]

Ecology[edit]

Polygala species are used as food plants by the larvae of some Lepidoptera species including Large Grizzled Skipper.

Uses[edit]

Some species are valued in cultivation. The hybrid evergreen shrub P. × dalmaisiana (P. myrtifolia × P. oppositifolia) has gained the Royal Horticultural Society's Award of Garden Merit.[4]

Diversity[edit]

The reported number of valid species in the genus varies from about 350[5] to 500[1][2] to 725[6] or 730.[7] The Americas have the most species, especially South America,[7] with Africa second in diversity and Asia third.[6]

Species include:[8][9][10][11][12][13]

Polygala macradenia var. macradenia

References[edit]

  1. ^ a b c d e Polygala. Flora of China.
  2. ^ a b c d e f g Polygala. The Jepson eFlora 2013.
  3. ^ Coombes, A. J. (2012). The A to Z of Plant Names. USA: Timber Press. p. 312. ISBN 9781604691962. 
  4. ^ "RHS Plant Selector - Polygala × dalmaisiana". Retrieved 27 May 2013. 
  5. ^ Coelho, V. P. D. M., et al. (2008). Flora of Paraíba, Brazil: Polygala L.(Polygalaceae). Acta Botânica Brasilica 22(1), 225-39. (Portuguese)
  6. ^ a b Lüdtke, R., et al. (2013). The genus Polygala L.(Polygalaceae) in Southern Brazil. Hoehnea 40(1), 1-50. (Portuguese)
  7. ^ a b Pastore, J. F. B. and T. B. Cavalcanti. (2008). A New Species of Polygala (Polygalaceae) from Brazil. Novon 18(1), 90-93.
  8. ^ Polygala. North American species. USDA PLANTS.
  9. ^ Polygala: list of species. Flora of China.
  10. ^ GRIN Species Records of Polygala. Germplasm Resources Information Network (GRIN).
  11. ^ Polygala. FloraBase. Western Australian Herbarium.
  12. ^ Polygala. Atlas of Living Australia.
  13. ^ Polygala. Red List of South African Plants. SANBI.
  14. ^ a b Dickinson, T., et al. (2004). ROM Field Guide to Wildflowers of Ontario. Royal Ontario Museum, Toronto. McClelland and Stewart Ltd. p 336.