PURPLE LOOSESTRIFE (Lythrum salicaria) Lythraceae — Loosestrife family

-alien invasive, EXTREMELY invasive: "Each plant can produce up to 2.7 million tiny seeds which are viable for years." for more, see:
http://www.friendsofthewildflowergarden.org/pages/plants/purpleloosestrife.html
-stem - square, hairy within inflorescence
-leaves - opposite, hairy underneath
-12 stamens - 6 long with purple anthers, 6 short with orange anthers
- 3 types of flowers: "and the relative length of their pistils and stamens is variable"
http://www.illinoiswildflowers.info/weeds/plants/pp_loosestrife.htm
-buds are longish and purplish
-The calyx is striped, hairy, and has 5 to 6 longish teeth. Complete expose, here:
http://www.friendsofthewildflowergarden.org/pages/plants/purpleloosestrife.html
- plants are sold in nurseries - some nurseries say plants sold are sterile cultivars, however,
http://www.fs.fed.us/database/feis/plants/forb/lytsal/all.html
states, "Although some are purported to be sterile, crosses within and between cultivars and wild Lythrum spp. are often compatible, and identification of cultivars and crosses is problematic."
Wikipedia says it's very variable in leaf shape and degree of hairiness.

(Winged Loosestrife (L. alatum) is native - - among other differences from L. salicaria, the plant has stems with small, narrow wings that might look like ridges, and 6 stamens that extend out of the throat, and the style stays in the tube.
https://www.minnesotawildflowers.info/flower/winged-loosestrife )