Iodanthus pinnatifidus (Michx.) Steud. - Purple Rocket

Iodanthus pinnatifidus plant

Family - Brassicaceae

Stems - To +80cm tall, erect, simple to branching near apex, herbaceous, carinate, glabrous, from large taproot.

Iodanthus pinnatifidus stem

Leaves - Alternate, sessile, at least the lowest auriculate and partially clasping, serrate-dentate, glabrous, to 15cm long, +/-4cm broad, spatulate below, lanceolate above, acute to acuminate. The lowest leaves often somewhat pinnatifid.

Iodanthus pinnatifidus leaves

Inflorescence - Terminal and axillary racemes elongating in fruit to +30cm tall. Pedicels slightly elongating in fruit to 1cm long, tuberculate, typically perpendicular to axis of stem.

Flowers - Petals 4, clawed, light purple to lilac, glabrous. Claw to 8mm long. Limb to +3mm broad, 6-7mm long, truncate or obtuse at apex, spreading or reflexed. Stamens 6, 4 large and 2 small. Filaments glabrous, lilac at apex, whitish near base, to 8mm long. Anthers purple, 1.2mm long. Ovary purple, glabrous, 7mm long, terete. Sepals 4, erect, distinct, lilac below, green and scarious at apex, glabrous, to 6mm long, 2mm broad at base, cupped. Siliques ascending to spreading, to 4cm long, with beak to 2.5mm long.

Iodanthus pinnatifidus flowerFlowers close-up.

Iodanthus pinnatifidus calyxCalyx.

Flowering - May - June.

Habitat - Moist soils of flood plain forest and low woods.

Origin - Native to U.S.

Other info. - The plant is a textbook member of the Brassicaceae with 4 distinct petals, 4 distinct sepals, and 6 distinct stamens.
The plant is common in the habitats mentioned above but is typically found growing in conjunction with other, not so friendly, alluvial plants as Laportea canadensis and Rhus radicans.

Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 5-24-03.


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