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Published In: De Orchideis Europaeis Annotationes 20, 26, 35. 1817. (De Orchid. Eur.) Name publication detailView in Biodiversity Heritage Library

Project Name Data (Last Modified On 7/9/2009)
Acceptance : Accepted
Project Data     (Last Modified On 7/23/2009)


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13. Platanthera Rich. (rein orchis, fringed orchid)

Plants with the flowering stems from a fascicle of fleshy, sometimes tuberlike roots. Flowering stems glabrous, with racemes or spikes toward the tip. Leaves 1–9, green, alternate on the flowering stems (basal elsewhere) and grading into the bracts subtending the flowers, sessile, lanceolate to elliptic, glabrous. Sepals all similar, ovate to broadly elliptic in Missouri species, usually somewhat pouchlike, the upper sepal forming a shallow hood over the column. Lateral petals mostly arching upward and inward, overlapping under the upper sepal. Lip variously entire to lobed or fringed, spreading and somewhat downward arching, with a usually long (as long as or longer than the rest of the lip) spur produced from the base and positioned more or less parallel to the ovary or somewhat pendant. Column with 1 stamen, the anther with 2 pollen sacs separated by a thin or broad connective, each arm of which bears a viscidium (a sticky structure along the arm). Staminodes lacking. Capsules ascending, 5–25 mm long, elliptic in outline, strongly ribbed. Forty species, North America, Europe, Asia.

Platanthera is one of the largest of the several segregates of Habenaria, the largest native to North America. In the broad sense that is still accepted by a minority of botanists, Habenaria is a worldwide genus of nearly 700 species. In the strict sense, as accepted here, true Habenaria is a primarily tropical genus of about 600 species that is represented on the Coastal Plain of the southeastern United States by only 4 species. The main separations between these genera reside in details of floral morphology. See Coeloglossum for the treatment of another segregate of Habenaria that occurs in Missouri.


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1 Lip entire or minutely toothed or irregular, not fringed or lobed (2)
+ Lip fringed and/or lobed, sometimes also toothed (3)
2 (1) Spurs 7–12 mm long, strongly curved; lip usually with 3 well-defined teeth at the tip, rarely nearly entire, lacking a pair of teeth at the base 2 Platanthera clavellata
+ Spurs 5–6 mm long, not strongly curved; lip lacking 3 well-defined teeth at the tip, but with a pair of teeth at the base 3 Platanthera flava
3 (1) Lip deeply fringed, but not lobed; perianth orange 1 Platanthera ciliaris
+ Lip 3-lobed, sometimes also fringed; perianth not orange (4)
4 (3) Perianth pink to purple (5)
+ Perianth white, greenish white, or pale creamy-white (6)
5 (4) Margins of the lobes of the lip unevenly toothed or fringed less than a third the length of the lobe, the middle lobe sometimes with a short notch at the tip; viscidia of the 2 anther sacs 3.0–3.5 mm apart 6 Platanthera peramoena
+ Margins of the lobes of the lip deeply toothed to fringed, at least some of the divisions more than a third the length of the lobe; viscidia of the 2 anther sacs 1–2 mm apart 8 Platanthera psycodes
6 (4) Petals linear to narrowly oblanceolate, the tips pointed, entire or obscurely and minutely toothed; spur 8–17 mm long 4 Platanthera lacera
+ Petals broadly obovate to broadly spathulate, the tips broadly rounded to shallowly indented, sharply toothed or with a short fringe; spur 20–55 mm long (7)
7 (6) Sepals 7.0–8.5 mm long; column 3.5–4.5 mm long, the viscidia of the anther sacs 1.2–3.2 mm apart 5 Platanthera leucophaea
+ Sepals 11–13 mm long; column 5.5–7.5 mm long, the viscidia of the anther sacs 6.2–7.5 mm apart 7 Platanthera praeclara
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