Platanthera obtusata |
Platanthera purpurascens |
|
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blunt-leaf bog-orchid, blunt-leaf rein-orchid, blunt-leafed rein orchid, bluntleaf orchid, northern small bog orchid, one-leaf rein-orchid, small northern bog-orchid |
purple-petal bog orchid |
|
Habit | Plants 5.5–35 cm. | Plants 24–80 cm. |
Leaves | 1(–2, rarely), spreading-ascending on base of stem; bracts 0(–1, rarely); blade linear-oblanceolate, elliptic, or broadly obovate, 3.5–15 × 0.8–5 cm. |
few–several, abruptly diverging or sometimes ascending, scattered along stem; blade oblong to ovate or lanceolate, 5.5–16(–28) × 1–4.5 cm. |
Spikes | lax. |
very lax to dense, flowers sometimes irregularly grouped in fascicles. |
Flowers | resupinate, not showy, greenish white to yellowish green; corolla commonly whiter than calyx; lateral sepals reflexed; petals rhombic, lanceolate-falcate, margins entire; lip descending, linear, narrowly lance-rhombic, or linear-hastate, with median basal thickening, unlobed, 2.5–8(–10) × less than 1–2 mm, margins entire; spur slenderly conic, 3–8(–10) mm; rostellum lobes directed forward, wide-spreading, rounded-angular; pollinaria straight; pollinia remaining enclosed in anther sacs; viscidia orbiculate; ovary rather slender to stout, mostly 3–10 mm. |
resupinate, not showy, green to yellowish green, often suffused with blue or lip sometimes with red; lateral sepals spreading to reflexed; petals ovate- to lance-falcate, margins entire; lip descending to somewhat reflexed or projecting, lanceolate to ovate, sometimes with prominent suborbiculate basal dilation, without basal thickening, 4–8 × 1.5–3 mm; spur strongly clavate to scrotiform, 2–3 mm, apex obtuse; rostellum lobes strongly diverging, very small, rounded, obscure; pollinaria straight; pollinia remaining enclosed in anther sacs; viscidia orbiculate to oblong; ovary rather slender to stout, mostly 5–9 mm. |
2n | = 42, 63 (American, as Habenaria obtusata), 126 (Eurasian, as Habenaria obtusata). |
= 42 [63]. |
Platanthera obtusata |
Platanthera purpurascens |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Mesic to wet coniferous forest, forested fens, sphagnum bogs, stream banks, tundra, moist roadsides | Stream banks, shores, ditches, fens, seeping slopes, roadsides, commonly in thickets, open woods |
Elevation | 0–3500 m (0–11500 ft) | 2500–3300 m (8200–10800 ft) |
Distribution |
AK; CO; ID; MA; ME; MI; MN; MT; NH; NY; OR; UT; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; Eurasia [Platanthera obtusata subsp oligantha]
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AZ; CA; CO; NM; WY
|
Discussion | The rare Eurasian Platanthera obtusata subsp. oligantha (Turczaninow) Hultén differs from the North American subsp. obtusata in its smaller dimensions and rhombic-lanceolate lip. It is also said to be densely few-flowered, although some Siberian material is comparable to American plants. Supposedly intermediate plants are reported from Alaska, and much material from that area is reduced in stature and with smaller flowers than typical of American plants. In most cases, however, lips are relatively slender, and the plants seem merely to be stunted by their environment. One or two collections from the Alaskan Peninsula and Aleutians, however, seem entirely referable to subsp. oligantha with dense, few-flowered inflorescences of very small flowers with rhombic-lanceolate lips and shorter curved spurs. Eurasian plants are reported to be hexaploid or perhaps sometimes triploid, and if the apparent ploidy differences delimit the taxa, then it should be possible to unequivocally identify Alaskan plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Flowers of Platanthera purpurascens are strongly semen scented, and their musty scent is markedly different than the sweet and spicy scents of other fragrant species. In some areas this species hybridizes with Platanthera dilatata var. albiflora, producing sweetly fragant plants with lanceolate green lips. At the southern edge of its range, however, it often occurs with similar plants in the absence of another putative parent. The identity of these plants is uncertain. Their rather generalized morphology might mask polyphyletic origins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26, p. 556. | FNA vol. 26, p. 560. |
Parent taxa | Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera | Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera |
Sibling taxa | ||
Synonyms | Orchis obtusata, Habenaria obtusata, Habenaria obtusata var. collectanea | Limnorchis purpurascens, P. hyperborea var. purpurascens |
Name authority | (Banks ex Pursh) Lindley: Gen. Sp. Orchid. Pl., 284. (1835) | (Rydberg) Sheviak & W. F. Jennings: N. Amer. Native Orchid J. 3: 445. (1997) |
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