Lythrum alatum Pursh - Winged Loosestrife

Lythrum alatum plant

Family - Lythraceae

Stems - To +1m tall, erect, herbaceous to woody below, 4-angled, branching above, glabrous. Angles slightly winged.

Lythrum alatum stem

Leaves - Mainly opposite to subopposite or with some alternate near apex, sessile, oblong, entire, acute, glabrous, to 5cm long, +1cm broad. Margins sparse stigillose.

Lythrum alatum leaves

Inflorescence - Single or paired flowers from leaf axils in upper portion of stems. Leaves greatly reduced in inflorescence to small bracts. Flowering portion of stem to +25cm long. Pedicles -1mm long, with two minute opposite bracts.

Flowers - Petals 6, pinkish-purple or rose-pink, 5mm long, 2.2mm broad, borne at edge of floral tube, with purple midvein. Stamens 6, unequal, adnate about 1/2 way up floral tube, included. Filaments glabrous, 5mm long, purplish. Anthers purple, .2mm broad. Style glabrous, white, exserted. Stigma globose-capitate, greenish. Floral tube to 6mm long, 1.1mm in diameter, glabrous, 12-nerved, with 6 appendages. Appendages alternating with calyx lobes, linear, to 1mm long, spreading. Calyx lobes acute, .5mm long, triangular.

Lythrum alatum calyxFloral tube.

Lythrum alatum flowerCorolla.

Flowering - May - September.

Habitat - Wet meadows and prairies, open wet glades, fens, stream and pond margins, railroads.

Origin - Native to U.S.

Other info. - This species can be found throughout Missouri but is mostly absent from the bootheel portion of the state. The plant has both alternate and opposite leaves. It can be easily identified by its pinkish-purple flowers, winged stems, and habitat.
This is the native and good member of the genus Lythrum represented in Missouri. We also have the dreaded L. salicaria L.which is nothing short of a noxious weed. Both plants are striking but only L. alatum belongs. It can make a good garden subject for moist or wet areas.

Photographs taken at the Shut-In Mountain Fen, Shannon County, MO., 6-25-04.


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