Stachys tenuifolia Willd. - Smooth Hedge Nettle
Family - Lamiaceae
Stems - To +1.2m tall, 4-angled,
herbaceous, hollow, branching above, erect, retrorse strigose on angles,
glabrous between angles, from rhizomes.
Rhizome.
Leaves - Opposite, decussate,
petiolate. Petiole to -3cm long, winged, glabrous or with sparse pubescence
at base. wing to -1mm broad. Blade lanceolate to lance-oblong, to +13cm
long, 4cm broad, crenate-serrate, acuminate, glabrous but with a scabrous
midrib.
Inflorescence - Terminal
spikiform arrangement of verticillasters. Verticillasters with +/-6 flowers,
subtended by small foliaceous bracts. Flowers sessile to subsessile.
Flowers - Corolla bilabiate,
pinkish with purple streaks and spots internally. Corolla tube to 7mm long,
glabrous, white near base. Upper lip of corolla 5mm long, 4mm broad, glandular
pubescent externally, glabrous internally, obtuse at apex. Lower corolla
lip 3-lobed, glabrous internally and externally. Lateral lobes -2mm long.
Central lobe 3mm long, 3.5mm broad. Stamens 4, didynamous, adnate at apex
of corolla tube, exserted from upper lip of corolla. Filaments to 3mm long,
glandular pubescent, white. Anthers brownish-purple, 1.2mm long. Style
white to purple at apex, 1.1cm long, glabrous. Stigma 2-lobed. Ovary of
4 nutlets. Nutlets greenish-white, 3-ribbed, becoming black and 1.7mm long
in fruit.
Calyx tube to 2.5mm long, sparse pubescent, 5-lobed. Lobes equal, attenuate, 2.5mm long, typically glabrous.
Calices, corollas removed.
Flowers close-up.
Flowering - June - September.
Habitat - Moist and low woodland, ravines, streambanks, pond margins, swamps, wet meadows.
Origin - Native to U.S.
Other info. - Stachys tenuifolia
and the similar S. palustris L. would make
excellent garden subjects for anyone with a shade garden and moist to wet
ground. The flowers are good for attracting flying insects and are striking
to look at.
Steyermark breaks S. tenuifolia
into two varieties. Variety tenuifolia, described
above, has petioles to 3cm long and is glabrous on the leaves, calyx, and
calyx lobes. This variety is found throughout most of the state. Variety
hispida (Pursh) Fern. has petioles to 8mm long and
is hispid to appressed pubescent on the leaves, calyx, and calyx lobes.
This variety is mostly found in the upper half of the state, north of the
Missouri river.
Photographs taken in the Irish Wilderness, Mark
Twain National Forest, Oregon County, MO., 7-15-00.
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