Platanthera grandiflora
Platanthera praeclara
greater purple fringe bog-orchid, greater purple fringe orchid
Great Plains white fringe orchid, western prairie fringe orchid
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.
several to many, ascending, scattered along stem, imperceptibly reduced to bracts distally;
blade lanceolate to ovate-lanceolate, to 26 × 5 cm.
lax to rather dense.
lax.
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, 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.
= 42.
= 42.
Platanthera grandiflora
Platanthera praeclara
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.)
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.)
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