Spiranthes cernua (L.) Rich. - Nodding Ladie's Tresses

Spiranthes cernua plant

Family - Orchidaceae

Stems - Aerial stems green, glabrous below, densely short glandular pubescent just below the inflorescence, to +50cm tall, erect, herbaceous, simple, terete, 3-5mm in diameter, single from the base.

Leaves - Mostly basal, few, linear to linear-oblong, to 25cm long, 2.5cm broad, present or (typically) absent at anthesis. Cauline leaves reduced to scales. The scalelike leaves to 3cm long, sheathing, acuminate, entire, glabrous 3-6 per stem.

Inflorescence - Terminal twisted spike to +/-12cm long. Flowers in two ranks, sometimes the two ranks are so mingled that no spiraling is visible. Flowers sessile. Each flower subtended and partially enveloped by a single acuminate bract. Bracts to +/-1.2cm long, +/-5mm broad (at the base), pubescent, with broad scarious margins in the basal 1/2, the apices abruptly acuminate.

Flowers - Corolla white, to +1cm long, slightly drooping. Lateral sepals white, with in-rolled margins, running parallel to the rest of the flower, pubescent, 7-8mm long, subulate. Upper 3 petals white, 7-11mm long, -2mm broad, appearing connate and forming the upper lip of the flower, pubescent. Lower petal white, more stout than the upper petals, 7-11mm long, 3-4mm broad, crisped (sometimes slightly) at the apex, somewhat folded, mostly glabrous, with two basal projections to 1.5mm long. The projections slightly retrorse, densely pubescent except at the apex. Pollinia 3mm long, with their bases (terminator) facing forward and slightly exserted from the column. Terminator brownish-red. Column 3-4mm long, with a brownish-red triangular lobe and two greenish lobes at the apex. Floral tube green, 5-6mm long, densely pubescent.

Spiranthes cernua flowers

Flowering - August - November.

Habitat - Acidic glades, dry upland prairies, wet meadows, thickets.

Origin - Native to U.S.

Other info. - This is a very common orchid in this state. The plants species name means "nodding" and the flowers do nod slightly. This species can be differentiated from others in the genus by its big flowers, which have the lateral sepals paralleling the sepals, and its lack of basal leaves at anthesis.

Photographs taken in Tuftonboro, NH., 10/2000.


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