Platanthera obtusata |
Platanthera hyperborea |
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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 |
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Habit | Plants 5.5–35 cm. | Plants 7–35 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, ascending to arcuate-spreading, scattered along stem or clustered at base, sometimes in basal rosette, gradually reduced to bracts distally; blade elliptic-oblong to ovate-oblong or linear-lanceolate, 3–14 × 0.4–4 cm. |
Spikes | lax. |
lax to very dense. |
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 but sometimes conspicuous, yellowish or perhaps whitish green; lateral sepals spreading to slightly reflexed; petals ovate-falcate, margins entire; lip descending, usually ovate with abruptly dilated base or occasionally lanceolate with less prominent dilation, without basal thickening, 4–5.5(–6) × (1.5–)2–2.5 mm; spur clavate, somewhat tapering toward obtuse apex, 4–6 mm; rostellum lobes divergent, directed downward, very small, obscure, rounded; pollinaria straight; pollinia often protruding from anther sacs, commonly fragmenting and pollen masses trailing onto stigma; viscidia linear to linear-oblong; ovary rather slender to stout, mostly 6–10 mm. |
2n | = 42, 63 (American, as Habenaria obtusata), 126 (Eurasian, as Habenaria obtusata). |
= 84. |
Platanthera obtusata |
Platanthera hyperborea |
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Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Mesic to wet coniferous forest, forested fens, sphagnum bogs, stream banks, tundra, moist roadsides | Wet tundra, stream banks |
Elevation | 0–3500 m (0–11500 ft) | 0 m (0 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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Greenland; Iceland |
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.) |
The relationship between Platanthera hyperborea and P. huronensis is unclear. Typical Icelandic material differs from P. huronensis in its shorter, broader, more extremely dilated, and evidently often yellowish lip; shorter, more strongly clavate spur; and narrower viscidia. The plants furthermore appear to be autogamous. Most Greenland material appears to be entirely comparable to these Icelandic plants. In both areas, however, considerable variation occurs, and some plants suggest P. huronensis. Whether this variation reflects the occurrence in these areas of two taxa or is within P. hyperborea is unknown. Platanthera hyperborea refers to a bewildering complex that has defied satisfactory treatment. The number and delimitation of species, indeed, the nature of species, in the group is unclear. The system proposed here utilizes more characters than past attempts and it is to be hoped it is an improvement over its predecessors, but it is far from definitive. Hybridization is frequently invoked as an explanation for much of the variation encountered in the group, and some of the possible crossings have been given names. Until species can be properly delimited, however, it is premature to recognize putative hybrids with formal epithets. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26, p. 556. | FNA vol. 26, p. 559. |
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 | Orchis hyperborea, Habenaria hyperborea, Limnorchis hyperborea |
Name authority | (Banks ex Pursh) Lindley: Gen. Sp. Orchid. Pl., 284. (1835) | (Linnaeus) Lindley: Gen. Sp. Orchid. Pl., 287. (1835) |
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