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Key to terrestrial orchids: Key to Orchidaceae

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1 Leaves absent at flowering, or with a solitary leaf with a purplish undersurface withering at about the time of flowering.

Show caption*© Richard & Teresa Ware   2 Flowers with a spur.

3 Spur shortly obtuse, lip partially tubular; [s. FL]  Galeandra bicarinata

Show caption*© Richard & Teresa Ware     3 Spur long and slender, lip not partially tubular; widespread in our region, south in FL to ne. FL]  Tipularia discolor

Show caption*© Alan M. Cressler Show caption*© Richard & Teresa Ware   2 Flowers without a spur.

4 Flowers white, the lip, sepals, and petals all predominantly white.

5 Lip white with a single central green stripe; leaves often fugacious  Beloglottis costaricensis

5 Lip white, centrally yellow to greenish-white, occasionally with multiple green veins (as in S. praecox and S. sylvatica); leaves present, absent, or withering (fugacious) at flowering  Spiranthes

4 Flowers pink, greenish, yellowish, or purplish, the lip sometimes white or marked with white, the sepals and petals colored.

6 Lip strongly bearded.

7 Flower solitary; [Mountains of SC, NC, and VA northwards]  Arethusa bulbosa

7 Flowers not solitary (inflorescence a raceme); [Coastal Plain of SC southwards]  Eulophia graminea

6 Lip not bearded.

8 Lip with 2 fleshy keels near the base; pollinia 4; plants holomycotrophic (without chlorophyll) and never with leaves  Corallorhiza

8 Lip with 3-7 keels near the base or extending most of the length of the lip; pollinia 4 or 8; plants either holomycotrophic (without chlorophyll) and never with leaves, or with a plicate winter leaf withering shortly before flowering.

9 Plants with a plicate winter leaf withering shortly before flowering (the withered remnant usually detectable); veins of the petals and sepals not strikingly different in color than the intervein areas; lip with 3 ridges; pollinia 4  Aplectrum hyemale

9 Plants never with leaves, holomycotrophic (without chlorophyll); veins of the petals and sepals strikingly different in color than the intervein areas; lip with 5-7 ridges; pollinia 8  Hexalectris

1 Leaves present at flowering (Cleistesiopsis with a foliaceous bract at the summit of the stem).

10 Plants with evident, above-ground pseudobulbs, sometimes enclosed by sheaths.

11 Leaf bases tightly sheathing the stems, often petiolate.

12 Lip broadest near its base; inflorescence typically a spicate raceme (prematurely umbellate in M. spicata); leaves to 10 cm long  Malaxis

12 Lip broadest near its apex; inflorescence typically a more open or lax raceme; leaves to 30 cm long.

13 Leaves 3-7, membranaceous, plicate; anthers green  Diteilis nervosa

13 Leaves 2, thickish, conduplicate; anthers yellow  Liparis

11 Leaf bases not conspicuously clasping the stems (or if clasping, loosely so).

14 Flowers predominantly yellow, pseudobulbs > 8 (-100) cm long.

Show caption*© Roger L. Hammer Show caption*© Roger L. Hammer                               15 Flowers without brown spots; pseudobulbs typically 10-30 (-100) cm long  Cyrtopodium polyphyllum

Show caption*© Roger L. Hammer                               15 Flowers with brown spots; pseudobulbs typically 8-15 cm long  Oncidium ensatum

14 Flowers not predominantly yellow, pseudobulbs < 8 cm long.

Show caption*© Aidan Campos                                 16 Leaves not plicate, with conspicuous dark green mottling  Oeceoclades maculata

Show caption*© Matt, some rights reserved (CC BY-NC), uploaded by Matt                                 16 Leaves plicate, without conspicuous dark green mottling.

Show caption*© Alan M. Cressler                                   17 Lip conspicuously bearded (or if not bearded, conspicuously keeled and with brownish-maroon veins extending to margins of lip)  Eulophia

17 Lip not conspicuously bearded.

Show caption*© Matt, some rights reserved (CC BY-NC), uploaded by Matt                                     18 Perianth brown (white on lower surface); lip tubular  Phaius tancarvilleae

18 Perianth pink or purple; lip not tubular.

Show caption*© Alan Cressler: Bletia patula, near Arecibo Observatory, Municipio de Arecibo, Puerto Rico 2 by Alan Cressler                                        19 Lip with 5-7 conspicuous yellow-white keels  Bletia

Show caption*© Alan Cressler: Spathoglottis plicata, Riviere Glace Valley, Grand Anse Department, Haiti 1 by Alan Cressler                                        19 Lip without 5-7 conspicuous yellow-white keels  Spathoglottis plicata

10 Plants without above-ground pseudobulbs (either absent or subterranean).

20 Leaf solitary.

21 Leaf basal.

22 Flower with a spur.

23 Leaf long petiolate, lanceolate-elliptic; lateral sepals conspicuously spreading with long acuminate apices; [s. FL]  Eltroplectris calcarata

23 Leaf not long petiolate, orbicular; lateral sepals reflexed or slightly spreading without long acuminate apices, rather, typically blunt or rounded; [widespread; NC and TN northward]  Platanthera

22 Flower without a spur.

24 Flower solitary  Arethusa bulbosa

24 Flowers in a raceme or spike.

25 Flowers relatively large, primarily pink, purple, or white; flowers arranged in loosely arranged racemes

26 Lip below (resupinate); flowers white, often cleistogamous; lip white with purple margins, with keels  Basiphyllaea corallicola

26 Lip above (not resupinate); flowers purple or pink (rarely white), chasmogomous; lip with yellow fringes (beard)  Calopogon

25 Flowers relatively small, whitish; flowers arranged in densely (and sometimes also spirally) arranged spikes.

27 Dorsal sepal connivent with petals forming hood over column; lip sagittate-auriculate  Pelexia adnata

27 Dorsal sepals not forming connivent hood with petals, or if rarely so, then lip pandurate (as in S. romanzoffianum)  Spiranthes

21 Leaf cauline.

28 Flowers in spikes or racemes, 5-many, reddish, yellowish, or greenish.  Platanthera

28 Flower solitary (-4), pink (rarely nearly white); [subfamily Vanilloideae; tribe Pogonieae].

29 Sepals brown to purple, linear or narrowly oblanceolate, 3-6.5 cm long, about 5 mm wide; leaf coriaceous  Cleistesiopsis

29 Sepals pink (rarely white), elliptic or oblanceolate, 1.3-2.7 cm long, 3-11 mm wide; leaf herbaceous  Pogonia ophioglossoides

20 Leaves 2-many.

30 Lip inflated, pouch-like or slipper-like, 2-6 cm long  Cypripedium

30 Lip not inflated, or if so, then 0.3-1.1 cm long.

31 Leaves cauline.

32 Leaves plicate; lip saccate or arcuate

33 Lip arcuate, with purple-brown marginal speckles; leaf sheaths inflated-tubular  Govenia floridana

33 Lip saccate, without purple-brown marginal spots; leaf sheaths tight and not inflated-tubular.

34 Leaves typically many (3-14); 4-20 cm long; lip variously colored without conspicuous yellow disc; [widespread]  Epipactis

34 Leaves typically fewer (2-5); 4-4.5 cm long; lip primarily white with conspicuous yellow disc; [s. FL]  Tropidia polystachya

32 Leaves smooth, often creased at the midrib, but not plicate; lip not saccate.

35 Leaves whorled, terminating the stem; [subfamily Vanilloideae; tribe Pogonieae]  Isotria

35 Leaves alternate or opposite, not terminating the stem.

36 Leaves 2, opposite, near the middle of the stem  Neottia

36 Leaves (2-) 3-many, alternate, variously distributed on the stem.

37 Plant with aerial roots throughout stem; lip orange-red, deeply 3 to 4 lobed and marginally fimbriate; [subfamily Epidendroideae]  Epidendrum radicans

37 Plant without aerial roots throughout stem; lip variously colored, if orange then not deeply 3 to 4 lobed.

38 Lip without a spur; leaves 0.8-8.0 cm long.

39 Distal portion of lip not uniformly yellow; leaves ovate, 0.4-2.0 cm long  Triphora

39 Distal portion of lip uniformly yellow; leaves linear or narrowly lanceolate, 1-8 cm long  Zeuxine strateumatica

38 Lip with a spur; leaves linear, lanceolate, or narrowly elliptic, 5-40 cm long (at least the larger > 5 cm long, except in Aspidogyne, with lanceolate to ovate leaves 1.5-6.5 cm long).

40 Leaves 1.5-6.5 cm long, with inflated tubular sheaths; plants from creeping rhizomes  Aspidogyne querceticola

40 Leaves 5-40 cm long, sessile; plants from fleshy or fusiform roots.

41 Lip divided into 3 linear divisions, the divisions not further divided, fringed, or eroded  Habenaria

41 Lip not divided into 3 divisions, or divided into 3 divisions but the divisions not linear.

42 Spur saccate, 2-3 mm long, the orifice minute  Dactylorhiza viridis

42 Spur elongate and slender, 4-50 mm long, the orifice larger  Platanthera

31 Leaves basal (sometimes with bladeless sheaths upward on the stem).

43 Leaves plicate.

44 Lip oriented upward (not resupinate); flowers pink to white  Calopogon

44 Lip oriented downward (resupinate); flowers greenish, purplish-brown, maroon or yellowish.

45 Sepals ascending or apically reflexed, not converging  Eulophia

45 Sepals converging, not ascending or reflexed  Orthochilus ecristatus

43 Leaves smooth, often creased at the midrib, but not plicate.

46 Lip with a spur.

47 Leaves long petiolate, not basally sheathing stems; sepals longer (to 30 mm), narrowly lanceolate  Eltroplectris calcarata

47 Leaves not long petiolate, basally sheathing stems; sepals shorter, variously shaped

48 Flowers bicolored, the lip white, the sepals and petals pink; leaves 2  Galearis spectabilis

48 Flowers not bicolored, the lip, petals, and sepals similarly colored; leaves 2-5

49 Lip deeply divided into 3 linear segments; leaves 3-5  Habenaria

49 Lip entire; leaves 2  Platanthera

46 Lip without a spur.

50 Leaf blade or leaves ascending.

51 Inflorescence a raceme; lip with pink-purple coloration along margin; flowers larger, not tightly spiraling  Basiphyllaea corallicola

51 Inflorescence a spike; lip without pink/purple coloration along margin; flowers smaller, often spiraling or tightly assembled  Spiranthes

50 Leaf blades more-or-less horizontally oriented, flat against the ground or 1-2 cm above it.

52 Flowers orange-red (except rarely light green as in S. lanceolata forma albidaviridis)  Sacoila

52 Flowers never strongly orange-red, instead white, yellowish, greenish, or brown (including coppery).

53 Lip oriented upward (flowers not resupinate).

54 Lip with green spots  Cranichis muscosa

54 Lip without green spots (sometimes with green coloration but not green-spotted).

55 Large flowers distinctly pedicellate on racemes; lip short-caudate, 4.5-7 mm long; petals obliquely triangular  Ponthieva

55 Minute flowers sessile on spikes; lip apiculate, 1-2 mm long; petals narrowly obovate  Prescottia oligantha

53 Lip oriented downward (flowers resupinate).

56 Leaves with prominent white or pale green variegation on midrib and/or veins; [subtribe Goodyerinae]  Goodyera

56 Leaves without prominent variegation; [subtribe Spiranthinae].

57 Flowers brown or copper colored  Mesadenus lucayanus

57 Flowers white or green colored.

58 Lip and perianth segments each with a single central green stripe; leaves more or less fugacious  Beloglottis costaricensis

58 Lip and perianth without a central green stripe; occasionally with multiple green veins on the lip; leaf often persistent.

59 Flowers white, often also marked or veined with yellow or green; [widespread in our region]  Spiranthes

59 Flowers green, greenish-yellow, or bronze; [FL southwards]

60 Lip canaliculate (grooved longitudinally), without conspicuous yellow throat; flowers greenish-brown or coppery  Cyclopogon

60 Lip not grooved longitudinally, with conspicuous yellow throat; flowers greenish-white  Pelexia adnata