Platanthera grandiflora
Platanthera chapmanii
greater purple fringe bog-orchid, greater purple fringe orchid
Chapman's 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.
1–3, spreading to ascending, abruptly or gradually reduced to bracts distally;
blade linear-lanceolate or lanceolate to lance-oblong, 15–26 × 1–3 cm.
lax to rather dense.
rather dense.
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, orange to pale dull yellow;
dorsal sepal entire or emarginate;
lateral sepals reflexed;
petals linear to obovate, apically fringed to merely lacerate-dentate;
lip porrect, ovate to ovate-orbiculate, without basal thickening, 5–10 × 4–9 mm, margins deeply filiform-fringed;
spur slenderly cylindric, 8–17 mm;
rostellum lobes directed downward, distally retrorse, digitate;
pollinaria with stalks recurved;
pollinia remaining enclosed in anther sacs;
viscidia orbiculate to suborbiculate;
ovary slender, 10–19 mm.
= 42.
Platanthera grandiflora
Platanthera chapmanii
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.)
as hybrid
The retrorse rostellum lobes of Platanthera chapmanii usually separate small-flowered plants of this species from P. cristata, which normally presents the viscidia forward on only slightly curved lobes. Additionally, the nearly circular mouth of the spur of P. chapmanii is in contrast to the triangular opening of P. cristata. Until recently P. chapmanii was confused with the hybrid of P. ciliaris and P. cristata, P. ×channellii Folsom, which is readily recognized by its angular rostellum lobes that are directed forward and outward, presenting the viscidia forward, as in its parents (J. P. Folsom 1984).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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