Spiranthes magnicamporum Sheviak
Great Plains Ladies' Tresses
CC = 7
CW = 3
MOC = 33
Family - Orchidaceae
Habit - Perennial forb, lacking rhizomes.
Stem - Erect, to 50 cm, unbranched, with sparse to dense, glandular hairs.
Leaves - Basal leaves 3 or 4, absent at flowering time, 5-14 cm long, linear, glabrous. Stem leaves alternate, reduced to small sheathing bracts.
Inflorescences - Dense terminal spikes, the flowers sessile and spirally arranged, usually appearing as though in 2 or more ranks or intertwined spirals along the flowering stems.
Flowers - Fragrant. Sepals and lateral petals 7-11 mm long, white, the lateral sepals free to the base or nearly so, spreading, the tips arching upward and angling away from the rest of the perianth. Lip 8-10 mm long, ovate to oblong, the margins somewhat irregular toward the tip, white, tinged with light yellow to yellowish tan in the middle of the inner surface. Stamen 1.
Fruits - Capsules, ascending, elliptic, 4-10 mm long, longitudinally ribbed.
Flowering - September - November.
Habitat - Dolomite glades, dry upland forest openings, fens, limestone glades.
Origin - Native to the U.S.
Lookalikes - Other species of Spiranthes, especially S. cernua.
Other info. - This small orchid is found in Missouri mostly in the south half of the state. It also occurs, in somewhat scattered fashion, thoughout most of the central U.S. Plants in the genus are easily identified as Spiranthes by their helical inflorescences of small white flowers. Identification to species can be more difficult. S. magnicamporum is characterized by robust inflorescences, which often appear doubly helical, and relatively large flowers with lateral sepals which are spreading and arching. The plant blooms late and is usually found on glades, or occasionally in lawns located in gladey regions with dolomitic substrate. In either case it can be fairly prolific. The flowers emit a sweetish fragrance of coumarin, which some people liken to vanilla.
Photographs taken at Victoria Glade, Jefferson County, MO, 10-7-2020 (SRTurner).