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greater purple fringe bog-orchid, greater purple fringe orchid

greater roundleaf orchid, large round-leaf orchid, large-leaf bog-orchid

Habit Plants 27–120 cm. Plants 23–63 cm.
Leaves

2–6, wide-spreading and recurved to somewhat ascending, scattered along stem, gradually reduced to bracts distally;

blade lanceolate, elliptic, oblong-elliptic, or oblong-obovate, 13–24 × 2.5–9 cm.

2, in subequal basal pair lying on ground;

bracts (very rarely, 0–)1–6, scattered along stem;

blade broadly elliptic, orbiculate, or oblate, 7–24 × 5–19 cm.

Spikes

lax to rather dense.

lax.

Flowers

resupinate, showy, lavender- to rose-purple, rarely white;

lateral sepals spreading to somewhat reflexed;

petals ovate, oblong, elliptic-oblong, or oblong-obovate, margins crenate to dentate-lacerate, sometimes nearly entire;

lip descending to somewhat porrect, deeply 3-lobed, without basal thickening, 10–25 × 14–26 mm, distal margins of lobes fringed, usually deeply, lateral lobes sometimes perpendicular to middle lobe, lateral lobes cuneate, often broadly so, middle lobe broadly cuneate-flabellate, often emarginate to 2-fid;

spur clavate, 15–35 mm;

rostellum lobes directed forward, spreading, angular;

pollinaria nearly straight;

pollinia remaining enclosed in anther sacs;

viscidia orbiculate;

ovary slender to stout, 12–25 mm.

resupinate, rather showy;

calyx mostly greenish white;

corolla mostly white;

lateral sepals reflexed to somewhat spreading;

petals lanceolate-falcate, margins entire;

lip descending to somewhat reflexed, linear-oblong to linear-lanceolate, without basal thickening, 10–23 × 1–2.5 mm, margins entire;

spur slenderly clavate, 28–46 mm;

rostellum lobes directed strongly forward, wide-spreading, angular;

pollinaria nearly straight, (4.6–)4.7–6.8 mm;

pollinia remaining enclosed in anther sacs;

viscidia orbiculate;

ovary slender to rather stout, mostly 16–29 mm.

2n

= 42.

Platanthera grandiflora

Platanthera macrophylla

Phenology Flowering Jun–Aug. Flowering Jun–Aug.
Habitat Alluvial and swamp forests, stream banks, seeping slopes, marshes, sphagnum bog forests, mesic wooded slopes, old fields Mesic to wet coniferous and deciduous forest
Elevation 0–1800 m (0–5900 ft) mostly 0–1000 m (mostly 0–3300 ft)
Distribution
from FNA
CT; MA; MD; ME; NC; NH; NJ; NY; OH; PA; RI; TN; VA; VT; WV; NB; NF; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; MA; ME; MI; MN; NH; NY; PA; VT; NB; NL; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Platanthera grandiflora is known to hybridize with P. lacera in the northeasternmost portion of its range, where the species bloom simultaneously. The name P. ×keenanii P. M. Brown has recently been proposed for these hybrids, but the complex synonymy of this group dictates that types be checked for possible priority. See the discussion under P. lacera. A few specimens also suggest very rare hybridization with P. psycodes (W. P. Stoutamire 1974).

Rare white-flowered plants may be separated from 23. Platanthera leucophaea by the orientation of the pollinia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 26, p. 565. FNA vol. 26.
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. hookeri, P. huronensis, P. hyperborea, P. integra, P. integrilabia, P. lacera, P. leucophaea, P. limosa, P. macrophylla, P. nivea, P. obtusata, P. orbiculata, P. peramoena, 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. limosa, P. nivea, P. obtusata, P. orbiculata, P. peramoena, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
Synonyms Orchis grandiflora, Habenaria fimbriata, Habenaria psycodes var. grandiflora Habenaria macrophylla, P. orbiculata var. macrophylla
Name authority (Bigelow) Lindley: Gen. Sp. Orchid. Pl., 294. (1835) (Goldie) P. M. Brown: Wild Fl. Notes 3: 23. (1988)
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