Flora of North America species comparison

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Platanthera peramoena

Platanthera limosa

purple fringeless orchid

Thurber's bog orchid
Habit Plants 35–105 cm. Plants 30–165 cm.
Leaves

2–5, spreading to ascending, scattered along stem, gradually reduced to bracts distally;

blade lanceolate, elliptic, oblong-elliptic, or oblance-oblong, 7–27 × 1.2–5 cm.

few to several, spreading-ascending on base of stem, gradually reduced to bracts upwards;

blade lanceolate, 9–28 × 1.2–3.5 cm.
Spikes

lax to dense.

dense to lax.
Flowers

resupinate, showy, rose-purple;

lateral sepals somewhat reflexed;

petals oblong-linear to spatulate, distally crenate to entire;

lip descending to somewhat porrect, deeply 3-lobed, without basal thickening, 11–20 × 12–23 mm, distal margins of lobes dentate-lacerate, rarely nearly entire, lateral lobes narrowly cuneate, middle lobe broadly cuneate-flabellate, emarginate to 2-fid;

spur clavate, 20–30 mm;

rostellum lobes directed forward, spreading, angular;

pollinaria straight to geniculate;

pollinia directed forward;

viscidia orbiculate;

ovary slender, 13–23 mm.

resupinate, inconspicuous, green;

lateral sepals reflexed to spreading;

petals lanceolate-, ovate-oblong-, or ovate-falcate, margins entire;

lip descending to reflexed, linear-oblong, linear-elliptic, or rhombic-ovate, usually with inconspicuous to scarcely discernable (possibly sometimes absent) median basal thickening, 2.5–8.5 × less than 1–3.5 mm, margins entire;

spur filiform, tapering toward apex, very rarely filiform-conic from slightly stout base, 8–25 mm;

rostellum lobes mostly parallel, closely spaced, directed downward, very small, rounded, obscure;

pollinaria straight;

pollinia remaining enclosed in anther sacs;

viscidia evidently elliptic-oblong;

ovary rather slender to stout, mostly 4.5–11 mm.

Platanthera peramoena

Platanthera limosa
Phenology Flowering (Jun–)Jul–Aug(–Oct). Flowering Jun–Aug.
Habitat Alluvial forests, wet wooded flats, stream banks, seeping slopes, marshes, moist prairies, old fields and pastures, ditches, thickets Open to lightly forested springy marshes, seeps, stream banks
Elevation 0–800 m (0–2600 ft) 1800–2500 m (– 4000 m, Central America) (5900–8200 ft (– 13100 ft, Central America))
Distribution
from FNA
AL; AR; DE; GA; IL; IN; KY; MD; MO; MS; NC; NJ; OH; PA; SC; TN; VA; WV
[WildflowerSearch map]
from FNA
AZ; NM; Mexico; Central America (to Guatemala)
[BONAP county map]
Discussion

Platanthera limosa is traditionally distinguished from other slender-spurred plants and from P. sparsiflora by the presence on the lip of a median thickening that culminates in a small basal process. Although diagnostic when present, this feature is often obscure, especially in live material, and seems to be lacking in some plants. Platanthera limosa is most consistently separated from other green-flowered species by the combination of very small, narrow column and slender spur much longer than the lip. These features are in contrast to the very large, broad columns of P. sparsiflora and P. zothecina and much shorter spurs of the P. hyperborea complex. The lips of most plants are elliptic to elliptic-oblong, unlike any other species except the Aleutian P. tipuloides, and such plants are readily determined by lip shape and spur characters. Within populations plants may vary greatly in flower size, spur shape and length, and the ratio of spur to lip length. Individual plants may vary markedly in size of the flowers and density of the inflorescence in different years. That situation warrants additional study, as it may obscure the presence of other taxa.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 26, p. 565. FNA vol. 26, p. 563.
Parent taxa Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera
Sibling taxa
P. aquilonis, P. blephariglottis, P. brevifolia, P. chapmanii, P. chorisiana, P. ciliaris, P. clavellata, P. convallariifolia, P. cristata, P. dilatata, P. flava, P. grandiflora, P. hookeri, P. huronensis, P. hyperborea, P. integra, P. integrilabia, P. lacera, P. leucophaea, P. limosa, P. macrophylla, P. nivea, P. obtusata, P. orbiculata, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
P. aquilonis, P. blephariglottis, P. brevifolia, P. chapmanii, P. chorisiana, P. ciliaris, P. clavellata, P. convallariifolia, P. cristata, P. dilatata, P. flava, P. grandiflora, P. hookeri, P. huronensis, P. hyperborea, P. integra, P. integrilabia, P. lacera, P. leucophaea, P. macrophylla, P. nivea, P. obtusata, P. orbiculata, P. peramoena, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
Synonyms Habenaria peramoena Habenaria limosa, Habenaria thurberi, Limnorchis arizonica
Name authority (A. Gray) A. Gray: Manual, 473. (1848) Lindley: Ann. Nat. Hist. 4: 381. (1840)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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