Platanthera obtusata |
Platanthera praeclara |
|
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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 |
Great Plains white fringe orchid, western prairie fringe orchid |
|
Habit | Plants 5.5–35 cm. | Plants 38–85 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. |
several to many, ascending, scattered along stem, imperceptibly reduced to bracts distally; blade lanceolate to ovate-lanceolate, to 26 × 5 cm. |
Spikes | lax. |
lax. |
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, showy, creamy white; lateral sepals somewhat porrect; petals flabellate, truncate, sometimes emarginate, apically lacerate; lip descending, deeply 3-lobed, without basal thickening, 17–32 × 20–39 mm, distal margins of lobes deeply incised and fringed, lateral lobes flabellate, sometimes broadly and overlapping middle lobe, middle lobe flabellate, sometimes very broadly, emarginate; spur slenderly clavate, 36–55 mm; rostellum lobes directed strongly forward, wide-spreading, angular; pollinaria geniculate; pollinia directed forward (column appearing hooded), remaining enclosed in anther sacs; viscidia orbiculate; ovary slender, mostly 20–30 mm. |
2n | = 42, 63 (American, as Habenaria obtusata), 126 (Eurasian, as Habenaria obtusata). |
= 42. |
Platanthera obtusata |
Platanthera praeclara |
|
Phenology | Flowering Jun–Aug. | Flowering (May–)Jun–Aug. |
Habitat | Mesic to wet coniferous forest, forested fens, sphagnum bogs, stream banks, tundra, moist roadsides | Mesic to wet prairies |
Elevation | 0–3500 m (0–11500 ft) | 200–800(–1600 m) (700–2600(–5200 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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IA; KS; MN; MO; ND; NE; OK; SD; WY; MB
|
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.) |
Of conservation concern. In Platanthera praeclara the wide-spreading rostellum lobes separate the viscidia by 6–7.5 mm, whereas in P. leucophaea the short rostellum lobes are more nearly parallel, and the viscidia are separated only by about 1–3.5 mm. These differences are immediately obvious on living material, but the measurements are nearly always impossible in herbarium specimens. In Wyoming Platanthera praeclara is known from a single, much higher station outside the usual range. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26, p. 556. | FNA vol. 26, p. 566. |
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 | Habenaria leucophaea var. praeclara |
Name authority | (Banks ex Pursh) Lindley: Gen. Sp. Orchid. Pl., 284. (1835) | Sheviak & M. L. Bowles: Rhodora 88: 278, figs. 1a–d, 2–4. (1986) |
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