Lythrum salicaria L. - Swamp Loosestrife
Family - Lythraceae
Stems - Multiple from base,
becoming woody at the base, herbaceous above, to 2m tall, 4-angled, scabrous, pubescent
to hispidulous, erect.
Leaves - Opposite to subopposite
in inflorescence, linear-lanceolate to oblong-linear, sessile, somewhat
clasping or not, entire, scabrous, +/-10cm long, +/-2cm broad, acute, reduced
upward, greatly reduced in inflorescence to foliaceous bracts.
Inflorescence - Dense terminal
spikes with clusters of 3-9 flowers per node. Flowers subtended by reduced
leaf(foliaceous bract). Bracts dense pubescent. Axis of inflorescence dense
pubescent to tomentose.
Flowers - Petals 5, borne
at apex of floral tube, to 7mm long, 3.5mm broad, glabrous, subequal, oblong-obovate,
pinkish-rose. Stamens 10-12, in two sets of five or six each. Longer set
of stamens well exserted. Filaments to 1.3cm long, adnate at base of floral
tube. Anthers purple. Shorter set of stamens included to slightly exserted.
Filaments white and fading to pinkish-purple at apex. Anthers yellow. Ovary
cylindrical-conic, 2.5mm long, 1mm in diameter, glabrous. Style 1mm long,
curved. Stigma glandular, capitate, green. Floral tube to 7mm long, 3mm
in diameter, cylindric, 12-nerved, dense pubescent, with 6 appendages.
Appendages linear-attenuate, 2-3mm long, greenish, alternating with calyx
lobes. Calyx lobes pink, to 1mm long, shorter than appendages, acute.
Flower close-up.
Calyx.
Flowering - June - September.
Habitat - Moist to wet ground
along ditches, streambanks, meadows, waste ground, prairies, roadsides,
railroads. Also cultivated.
Origin - Native to Europe.
Other info. - Efforts to
keep this plant under control in Missouri so far have met with moderate
success. The plant is rare in the wild and typically gets destroyed upon
its discovery. You can help too. If you find the plant in the wild, report
its location to Missouri Department of Conservation. This is no laughing
matter as anyone who has been to New England or the Northeast can attest.
The plant is highly invasive and can quickly spread through an area and
out-compete all native flora. It creates a sea of pink which may be pretty
to look at but is an environmental disaster. Don't be tempted to grow it
at home, find something else.
Photographs taken off Hwy 64, somewhere in the U.P. of Michigan, 9-7-03.
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