Pontederia cordata

Pickerelweed
Conservation status

Secure  (NatureServe)[1]
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Commelinales
Family: Pontederiaceae
Genus: Pontederia
Species: P. cordata
Binomial name
Pontederia cordata
L.

Pontederia cordata, common name pickerelweed (USA) or pickerel weed (UK), is a monocotyledonous aquatic plant native to the American continent. It grows in a variety of wetlands, including pond and lake margins across an extremely large range from eastern Canada south to Argentina. A few examples include northern rivers,[2] the Everglades[3] and Louisiana.[4]

Ecology

The species grows as an emergent plant, that is, in flooded conditions, so the plant is generally dependent upon aerenchyma in the stem to carry oxygen into the roots. Its metabolism, is, however, also tolerant of low soil oxygen.[5] It is often found in areas where water levels fluctuate naturally, with spring flooding and later summer emergence. Apart from flooding, the species is also influenced by soil fertility, tending to grow in the more fertile bays of large lakes, for example. Like many aquatic plants, it is negatively affected by salinity and grazing.[6] It is also negatively affected by competition from other wetland plants.[7] Like many wetland plants, it can survive unfavorable conditions as buried seeds in the soil.[8]

Flowers

The plant flowers in late summer. The purple flowers have yellow markings which may assist in attracting bees for pollination.[9] One bee species known to pollinate the flowers is Dufourea (Halictoides) novaeangliae.[10] Once the plant begins to produce seeds, the stem supporting the infloresence bends to submerse the fruits and seeds.[11] Seeds are dormant at the time of dispersal and will not germinate without stratification for 6-8 weeks.[12]

The flowers of the species are tristylous, meaning the styles of individual plants occur in three different morphs, with most populations containing all three. Leaf shape, which varies considerably across populations, within populations, and even within individuals, has been the source for many taxonomic synonyms.[13] Like many wetland and aquatic plants, the species can reproduce asexually by means of branching rhizomes, and hence can form large clonal stands.[14]

Pickerelweed near Ottawa, Ontario

Cultivation

This plant is cultivated as an ornamental garden plant, and has gained the Royal Horticultural Society's Award of Garden Merit.[15]

References

Wikimedia Commons has media related to Pontederia cordata.
  1. ↑ NatureServe (2006), "Pontederia cordata", NatureServe Explorer: An online encyclopedia of life, Version 6.1., Arlington, Virginia, retrieved 2010-07-25
  2. ↑ Day, R. T., Keddy, P. A., McNeill, J., and Carleton, T. (1988). Fertility and disturbance gradients: a summary model for riverine marsh vegetation. Ecology, 69, 1044–54.
  3. ↑ Loveless, C. M. (1959). A study of the vegetation in the Florida everglades. Ecology, 40, 1–9.
  4. ↑ Keddy, P. A., Campbell, D., McFalls T., Shaffer, G., Moreau, R., Dranguet, C., and Heleniak, R. (2007). The wetlands of lakes Pontchartrain and Maurepas: past, present and future. Environmental Reviews, 15, 1–35.
  5. ↑ Laing, H. E. (1940). Respiration of the rhizomes of Nuphar advenum and other water plants. American Journal of Botany, 27, 574–81.
  6. ↑ Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p
  7. ↑ Geho, E. M., Campbell, D., and Keddy, P. A. (2007). Quantifying ecological filters: the relative impact of herbivory, neighbours, and sediment on an oligohaline marsh. Oikos, 116, 1006–16.
  8. ↑ Whigham, Dennis F. and Robert L. Simpson. 1982. Germination and dormancy studies of Pontederia cordata L. Bulletin of the Torrey Botanical Club 109: 524-528.
  9. ↑ Sculthorpe, C. D. (1967). The Biology of Aquatic Vascular Plants. Reprinted 1985 Edward Arnold, by London. p. 280.
  10. ↑ Hutchinson, G. E. (1975). A Treatise on Limnology, Vol. 3, Limnological Botany. New York: John Wiley. p.229.
  11. ↑ Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Figure 6.9.
  12. ↑ Whigham, Dennis F. and Robert L. Simpson. 1982. Germination and dormancy studies of Pontederia cordata L. Bulletin of the Torrey Botanical Club 109: 524-528.
  13. ↑ Adanson, Narukila; Rafinesque, Umsema; Rafinesque, Unisema (2002), "Pontederia cordata", in Flora of North America Editorial Committee, eds. 1993+, Flora of North America 26, New York & Oxford: Oxford University Press, p. 45
  14. ↑ Hutchinson, G. E. (1975). A Treatise on Limnology, Vol. 3, Limnological Botany. New York: John Wiley.
  15. ↑ "RHS Plant Selector - Pontederia cordata". Retrieved 28 May 2013.

External links

Media related to Pontederia cordata at Wikimedia Commons