Prunella vulgaris L. - Heal-All

Prunella vulgaris plant

Family - Lamiaceae

Stems - To +40cm tall, erect (or rarely creeping), 4-angled (the angles minutely winged, the wing .3mm broad), glabrous to villous on angles or antrorse strigose, herbaceous, from fibrous roots, typically simple, single or multiple from base.

Prunella vulgaris stem

Leaves - Opposite, petiolate. Petioles +3c, long at base of plant, reduced above, villous, winged on upper leaves. Blades lance-ovate below, lanceolate above, to +/-6cm long, =2cm broad, entire or with a few shallow teeth, somewhat undulate, strigose.

Prunella vulgaris leaves

Inflorescence - Terminal dense 4-angled spike of verticillasters to +/-7cm tall(long), 1.5-2cm thick. Verticillasters each with 6 flowers(3 flowers per cymule). Cymules subtended by broad ciliate-margined bracts. Bracts decussate, abruptly acuminate, 1.6cm broad. Flowers sessile.

Prunella vulgaris inflorescence

Flowers - Corolla bilabiate whitish-purple. Corolla tube to 8mm long, glabrous. Upper lip galeate, purple, 6-7mm long, 5mm broad, with a few villous hairs externally on midvein. Lower lip 3-lobed. Lateral lobes 2-3mm long, 1.5mm broad. Central lobe 4mm long, deflexed, fimbriate-erose at apex, light purple. Stamens 4, didynamous, included under the galea, upper pair adnate near base of galea, lower pair adnate near base of corolla tube. Filaments purple, glabrous, the longest to 1.2cm. Anthers purplish-brown. Style inserted between upper pair of stamens, glabrous, lilac, 1.6cm long. Stigma 2-lobed. Ovary 4-parted. Calyx bilabiate, accrescent, 10-nerved. Tube to 5mm long in flower. Upper lip with three mucronate lobes, reddish-purple at apex.  Lower lip 2-lobed. Lobes acuminate, 3mm long in flower, reddish-purple. Calyx villous on margins and on nerves. Nutlets to 2mm long, brownish-yellow, glabrous.

Prunella vulgaris corollaCorolla, side-view.

Prunella vulgaris corollaFront-view.

Flowering - May - September.

Habitat - Waste ground, disturbed sites, open woods, pastures, roadsides, railroads.

Origin - Native to Europe, Asia, and North America.

Other info. - This is a very common species in this state. The plant is generally quite small and can bloom at just a few cm in height if it is growing in an area where it gets frequently cut or mowed. The species designation means "common" and is frequently used in botanical nomenclature to describe plants that are indeed common.
Steyermark busts the species apart into different varieties and forms. I won't go into those here but it is worth noting that our plants belong to variety lanceolata (Bart.) Fern. and the European plants belong to variety vulgaris. Both varieties can be found in Missouri but var. lanceolata is much more common.

Photographs taken off Hwy V, Shannon County, MO., 5-23-03.


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