Oshuna crassipes (Martius) A. Haines

Locations ofOshuna crassipes (Martius) A. Haines in Virginia

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Detail

Family
Pontederiaceae
Botanical Name
Oshuna crassipes (Martius) A. Haines
Common Name
Water Hyacinth
Synonym(s)
Eichhornia crassipes (Martius) Solms; Pontederia crassipes Martius; Piaropus crassipes (Martius) A. Haines
Flora of Virginia Name/Status
Pontederia crassipes Martius
Comments
Native of tropical South America, the water hyacinth is now one of the most invasive aquatic weeds in tropical and subtropical regions worldwide.

This taxon has been treated traditionally as Eichhornia crassipes. Recent arguments have been made for transferring Eichhornia to either Pontederia (Pellegrini et al. 2018, PhytoKeys 108: 25-83) or Piaropus (Haines 2020, Bot. Notes 15). Haines argues that the five monophyletic subgenera in Pellegrini et al's broad re-circumscription of Pontederia merit treatment as genera, and that Pellegrini et al provide the evidence and justification for doing so. It's a convincing argument, and we follow it here. However, Haines later determined that the name Pairopus was invalid, and provided a new name, Oshuna, for the genus; see Bot. Notes 16, 2021.
Habitat
Still and sluggish waters of lakes, ponds, ditches, and canals. Rare but locally abundant, Coastal Plain; well established in the cities of Hampton and Virginia Beach. This species was also recently discovered to be abundant in Lake Cook on Cameron Run in Fairfax County, a rather surprising northern range extension. It seems doubtful that the species is overwintering here, and further observations are needed to determine if it is functioning as an annual, re-seeding year to year.
Native Status
Introduced

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