Perennial semi-mycotrophic (saprophytic) herb 25 - 90 cm tall
Leaves: four to six, alternate, stalkless, more or less clasping, dark green, 4 - 18 cm long, 1.5 - 8.5 cm wide, broadly egg-shaped to elliptic or lance-shaped, non-toothed, often rough-hairy, and with obvious lengthwise ribs. The largest leaves on the plant tend to be near the middle of the stem.
Inflorescence: a single, erect, terminal, stalked, elongate (up to 30 cm), often one-sided, typically dense, spike-like cluster of six to fifteen (sometimes to 50), short-stalked flowers. Each flower is subtended by a single, green, leafy, obvious (often longer than flower), 1 - 4 cm long, about 0.5 cm wide, lance-shaped bract.
Flowers: pale green to whitish green or green streaked to entirely purple, 2 - 3 cm long, bilaterally symmetric, open (sepals partially spreading) with lowest petal formed into a lip, but lacking a spur. The reproductive parts of stamens, stigma and style are fused into a 3 - 6 mm long column above the hairless inferior ovary.
Sepals: three, spreading with tips curved forward or slightly downward, petal-like, pale pinkish to green, 0.6 - 1.5 cm long, 4 - 6 mm wide, egg- to lance-shaped, and prominently nerved. The central sepal partially covers the fairly erect column.
Petals: three, upper two pink-purple to green, 0.6 - 1 cm long, 3 - 6 mm wide, lance-shaped to elliptic, and lateral above highly-modified lip. The 1 - 1.5 cm long, 4 - 8 mm wide lip has two parts: a purplish brown deep cup-shaped, fleshy, nectar-filled base, which then narrows at a fleshy nodule before expanding into a pinkish to green, triangular to egg-shaped tip that curls under and back.
Fruit: several, stalked, erect or nodding, green with brownish vertical lines, inversely egg-shaped to ellipsoid, 0.9 - 1.4 cm long, hairy to nearly hairless capsules with remnant floral parts at tip and subtended by green bracts.
Flowering stem: single, erect, slender, elongate, green to purplish, with several leaves, and usually short-hairy at least above.
Root system: of slender, fibrous true roots and large underground rhizomes.
Similar species: Within the Chicago Region, Epipactis helleborine may be confused with Aplectrum hyemale, but that species blooms much earlier, is hairless, lacks stem leaves (only has sheaths), the single basal leaf is obviously pleated with white veins, the inflorescence is more loose with only tiny bracts, the flower sepals are much longer than the petals, the lip is not cup-shaped and lacks nectar, and the fruit droop. Some confusion could be possible with Coeloglossum viride, but it is usually smaller, the all green flowers are erect and very tightly appressed to the inflorescence axis, the sepals and petals form a hood over the column and straight lip. In Vermont another species of Epipactis has been introduced, but E. atrorubens has dark red to maroon flowers, long hairs on the ovary, and a shorter lip (only 5.5 - 6.5 mm). The native western species, E. gigantea differs from both of these non-native species since the flower lip is three-lobed, and the lateral sepals are much longer (1.6 - 2.4 cm).
Flowering: late June to mid-August
Habitat and ecology: Occasional, naturalized, floodplain banks with clay soils to sandy soil dune forests, though originally cultivated and typically escaping to disturbed areas along foot trails or roads within woodlands. As with many orchids, this species has a fungal partner from which it can gain nutrients. This is very important from the time of seed germination to growth of a leaf-bearing, flowering plant (Case 1987).
Occurence in the Chicago region: non-native
Notes: This is the only non-native orchid in the Chicago Region, with the area's first introduction (on purpose) around 1895 in Berrien Co., MI (Drew and Giles 1951). Claimed to be a potentially aggressive weed, the orchid has not spread very quickly in our area. The species was first planted in the United States around 1879 near Syracuse, NY by European immigrants, presumably for medicinal purposes (see Homoya 1993, pp. 115-116). The genus of approximately twenty species is primarily restricted to temperate Eurasia, with only E. gigantea</> being native to western North America.
Etymology: Epipactis is an ancient Greek name applied to a plant capable of curdling milk (possibly a hellebore). Helleborine means like a hellebore, in reference to this species' resemblance to some species in the genus Helleborus.
Author: The Field Museum
Reported from La Porte County by Nieuwland & Just (Amer. Midland Nat. 12: 220. 1931). They write: "Interlaken, Laporte Co., spreading very rapidly in abundance on a dry clay hillside facing the lake, VII. 18. 1930.) (Probably introduced.)" I have seen their specimens and I am admitting it upon their statement that it is spreading rapidly. Found in 1937 by Lyon in South Bend.
Erect from a short, praemorse rhizome, to 8 dm; lvs sessile and clasping, ovate to lanceolate, the lower to 10 cm, the upper progressively smaller; raceme 1-3 dm, many-fld, its bracts linear or narrowly lanceolate, the lower surpassing the fls; sep and lateral pet lance-ovate, 10-14 mm, acute, dull-green, strongly veined with purple; lip greenish and purple; 2n=36-44. Native of Europe, now widespread in our range along roadsides and in woods. July, Aug. (E. latifolia; Serapias h.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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