Platanthera lacera (Michx.) G. Don - Prairie Fringed Orchid

Habenaria lacera plant

Family - Orchidaceae

Stems - To +60cm tall, erect, herbaceous, simple, glabrous, from slightly thickened roots.

Leaves - Alternate, sheathing, glabrous. Lower leaves to +/-7cm long, +2cm broad, elliptic to oblong, entire. Upper leaves more dense, becoming linear-lanceolate, 2-3cm long, 5mm broad.

Habenaria lacera plantLower leaf.

Inflorescence - Terminal spikiform raceme to 15cm long. Flowers subtended by foliaceous bracts.

Habenaria lacera inflorescence

Flowers - Petals 3. Lowest petal to 2cm long, 2cm broad, whitish, deeply divided into 3 lobes, with basal spur. Lobes divided into linear segments, erose to lacerate, to 8mm long, glabrous. Spur to 1.6cm long, greenish-white. Lateral petals to 8mm long, greenish. Sepals 3, green. Upper sepal to +4mm broad, 5mm long. Lateral sepals to 4mm long, 1.3mm broad, linear, curling under lip of lower petal. Ovary +1.5cm long, 1.5mm in diameter, green, glabrous, sub-falcate. Fruit to +2cm long, 5mm in diameter, many seeded.

Habenaria lacera flowers

Habenaria lacera flowersIndividual flower.

Flowering - May - August.

Habitat - Prairies, open woods, pastures.

Origin - Native to U.S.

Other info. - This orchid is quite striking, as are most in the genus. The flowers emit fragrance at night and thus attract Sphinx Moths, (family Sphingidae), for pollination. This particular species is fairly common in the state but others in the genus are rare and threatened. Prairie restoration and protection will help immensely in insuring these plants survive.
Our plants belong to variety lacera. Another variety, var. terrae-novae Fern., has smaller flowers and is not found in Missouri.
A synonym is Habenaria lacera (Michx.) Lodd.

Photographs taken at Taberville Prairie, MO., 6-7-03.


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