Polanisia dodecandra (L.) DC. - Clammy Weed

Polanisia dodecandra plant

Family - Capparaceae

Stems - To +50cm tall, erect to reclining with age, herbaceous, branching, from a big taproot, glandular and arachnoid pubescent.

Polanisia dodecandra stem

Leaves - Alternate, trifoliolate, petiolate. Petioles to +2cm long, with an adaxial groove, pubescence as the stem. Terminal leaflet typically oblanceolate, entire, rounded to notched at apex, glandular pubescent on margins and midrib below, with some arachnoid pubescence below, to +3cm long, +1.3cm broad, its petiolule to 1mm long. Lateral leaflets on petiolules to -1mm long, with same pubescence as the terminal leaflet, obliquely oblanceolate, typically smaller than the terminal leaflet.

Polanisia dodecandra leaf

Inflorescence - Terminal and lateral bracteate racemes to +/-15cm long(tall). Each flower subtended by a foliaceous bract. Pedicels typically purplish, to 1.3cm long. Pubescence as with stem but more glandular.

Flowers - Petals 4, white to pinkish tinged, clawed. Claw to -3mm long. Limb to +3mm long, 3mm broad, notched at apex, glabrous. Stamens 8-13, erect, exserted. Filaments to 8mm long, mostly glabrous, purplish. Anthers greenish-purple, to +1mm long. Ovary superior, green and very small in flower, quickly expanding, cylindric, glandular pubescent, unilocular. Placentation parietal. Style glabrous, 1.5-2mm long, purplish-red. Adaxial side of flower with large nectary at its base. Nectary 1.5mm broad. Sepals 4, purplish-green, oblong-ovate, acute, glandular pubescent externally, glabrous internally, entire, to 4mm long, +2mm broad. Fruits glandular and arachnoid pubescent, slightly compressed, to +/-4cm long, greenish to reddish. Seeds 2-3mm in diameter, grooved.

Polanisia dodecandra flowerFlower close-up.

Polanisia dodecandra fruitFruit.

Flowering - May - October.

Habitat - Stream banks, bars, waste ground, roadsides, railroads.

Origin - Native to U.S.

Other info. - This species can be found scattered throughout Missouri. The plant is easy to identify becasue of its viscid stems and fruits, small white flowers, and three-lobed leaves.
There are two varieties in Missouri. var. dodecandra is found along gravel bars of streams and in open waste ground. This variety has smaller flowers than the next and is described above. Var. trachysperma (T. & G.) Iltis is found growing in glades and bluffs and has larger flowers than the previous variety.

Photographs taken at Logan Creek, Reynolds County, MO., 7-6-03, and at Big Spring Park, MO., 7-6-04.


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