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Key to terrestrial orchids: Key to Orchidaceae

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.
  2
Flowers with a spur.

(c) Ware, Richard & Teresa - CC-BY-NC, permission granted to NCBG
    3
Spur long and slender, lip not partially tubular nor bearded; widespread in our region, south in FL to ne. FL]
 ⇒ Tipularia discolor

(c) Ware, Richard & Teresa - CC-BY-NC, permission granted to NCBG
    3
Spur shortly obtuse or short-conic (usually somewhat rounded at the tip), lip partially tubular or conspicuously bearded
      4
Lip bearded, with evident fringed keels; [non-native of variously disturbed or cultivated habitats, occasionally occurring in pine rocklands]
 ⇒ Eulophia graminea
      4
Lip not bearded, lacking keels entirely (sometimes with magenta coloring but these not raised); [native of rockland hammocks in s. FL]
 ⇒ Galeandra bicarinata
  2
Flowers without a spur (the lip sometimes saccate but not extending further below as would a spur).

(c) Ware, Richard & Teresa - CC-BY-NC, permission granted to NCBG
(c) Cressler, Alan M.
    5
Flowers white, the lip, sepals, and petals all predominantly white.
      6
Lip white with a single central green stripe; leaves often fugacious
 ⇒ Beloglottis costaricensis
      6
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
    5
Flowers pink, greenish, yellowish, or purplish, the lip sometimes white or marked with white, the sepals and petals colored.
      7
Lip strongly bearded.

(c) Cressler, Alan M.
        8
Flower solitary; [Mountains of SC, NC, and VA northwards]
 ⇒ Arethusa bulbosa

(c) Brinker, Samuel - CC-BY-NC, permission granted to NCBG
        8
Flowers not solitary (inflorescence a raceme); [Coastal Plain of SC southwards]
 ⇒ Eulophia graminea

(c) Ward, Scott G
      7
Lip not bearded.

(c) Cressler, Alan M.
        9
Lip with 2 fleshy keels near the base; pollinia 4; plants holomycotrophic (without chlorophyll) and never with leaves
 ⇒ Corallorhiza
        9
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.
          10
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
          10
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

(c) Cressler, Alan M.
1
Leaves present at flowering (Cleistesiopsis with a foliaceous bract at the summit of the stem).
  11
Plants with evident, above-ground pseudobulbs, sometimes enclosed by sheaths (these sometimes partially apparent in Malaxis, if so the leaves usually tightly clasping the stems).

(c) Montes de Oca, Joseph - CC-BY-NC, permission granted to NCBG
(c) Matt - CC-BY-NC, permission granted to NCBG
(c) Montes de Oca, Joseph - CC-BY-NC, permission granted to NCBG
    12
Leaf bases tightly sheathing the stems, often petiolate.

(c) Cressler, Alan M.
      13
Lip broadest near its base (proximal); flowers resupinate (for those species in our flora area; excluding M. spicata) inflorescence typically a spicate raceme (sometimes prematurely appearing apically umbellate in M. unifolia); leaves to 10 cm long
 ⇒ Malaxis

(c) Cressler, Alan M.
(c) acjci - CC-BY-SA
      13
Lip broadest near its apex (distal); inflorescence typically a more open or lax raceme; leaves to 30 cm long.

(c) Ward, Scott G
(c) Cressler, Alan M.
        14
Leaves 3-7, membranaceous, plicate; anthers green
 ⇒ Diteilis nervosa

(c) Riella, Fabrício Mil Homens - CC-BY
        14
Leaves 2, thickish, conduplicate; anthers yellow
 ⇒ Liparis

(c) Danielson, Erik
    12
Leaf bases not conspicuously clasping the stems (or if clasping, loosely so).
      15
Flowers predominantly yellow, pseudobulbs > 8 (-100) cm long.
        16
Flowers without brown spots; pseudobulbs typically 10-30 (-100) cm long
 ⇒ Cyrtopodium flavum

(c) Hammer, Roger L.
(c) Hammer, Roger L.
        16
Flowers with brown spots; pseudobulbs typically 8-15 cm long
 ⇒ Oncidium ensatum

(c) Hammer, Roger L.
      15
Flowers not predominantly yellow, pseudobulbs < 8 cm long.
        17
Leaves not plicate, with conspicuous dark green mottling
 ⇒ Oeceoclades maculata

(c) Campos, Aidan
        17
Leaves plicate, without conspicuous dark green mottling.

(c) Matt - CC-BY-NC, permission granted to NCBG
          18
Lip conspicuously bearded or bearing bumpy projections
 ⇒ Eulophia

(c) Cressler, Alan M.
          18
Lip not conspicuously bearded, but sometimes with 3-7 distinct keels.
             19
Perianth primarily brown or green (white on the backs of the sepals and petals OR the lip greenish-white with brown lateral venation); lip tubular (Phaius) or not (Eulophia).

(c) Matt - CC-BY-NC, permission granted to NCBG
               21
Lip with 5-7 conspicuous yellow or white keels, the keels sometimes distally undulate.

(c) Cressler, Alan M.
                 22
Inflorescence arising basally (directly from the pseudobulb and on separate stems from the leaf culms)
 ⇒ Bletia
                 22
Inflorescence arising terminally (with leaves below and on the same culm)
 ⇒ Bletilla striata
               21
Lip without 5-7 conspicuous yellow-white keels
 ⇒ Spathoglottis plicata

(c) Cressler, Alan M.
  11
Plants without above-ground pseudobulbs (either absent or subterranean).
    23
Leaf solitary.
        25
Flower with a spur.

(c) Ward, Scott G
          26
Leaf long petiolate, lanceolate-elliptic; lateral sepals conspicuously spreading with long acuminate apices; [s. FL]
 ⇒ Eltroplectris calcarata

(c) Campos, Aidan
(c) Ward, Scott G
          26
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

(c) Cressler, Alan M.
© Floyd A. Griffith
        25
Flower without a spur.
          27
Flower solitary
 ⇒ Arethusa bulbosa

(c) Brinker, Samuel - CC-BY-NC, permission granted to NCBG
             28
Flowers relatively large, primarily pink, purple, or white; flowers arranged in loosely arranged racemes
               29
Lip below (resupinate); flowers white, often cleistogamous; lip white with purple margins, with keels
 ⇒ Basiphyllaea corallicola
               29
Lip above (not resupinate); flowers purple or pink (rarely white), chasmogomous; lip with yellow fringes (beard)
 ⇒ Calopogon

(c) Griffith, Floyd A.
             28
Flowers relatively small, whitish; flowers arranged in densely (and sometimes also spirally) arranged spikes.
               30
Dorsal sepals not forming connivent hood with petals, or if rarely so, then lip pandurate (as in S. romanzoffianum)
 ⇒ Spiranthes
        31
Flowers in spikes or racemes, 5-many, reddish, yellowish, or greenish.
 ⇒ Platanthera
        31
Flower solitary (-4), pink (rarely nearly white); [subfamily Vanilloideae; tribe Pogonieae].
          32
Sepals brown to purple, linear or narrowly oblanceolate, 3-6.5 cm long, about 5 mm wide; leaf coriaceous
 ⇒ Cleistesiopsis
          32
Sepals pink (rarely white), elliptic or oblanceolate, 1.3-2.7 cm long, 3-11 mm wide; leaf herbaceous
 ⇒ Pogonia ophioglossoides
    23
Leaves 2-many.
      33
Lip inflated, pouch-like or slipper-like, 2-6 cm long
 ⇒ Cypripedium
      33
Lip not inflated, or if so, then 0.3-1.1 cm long.
             36
Lip saccate, without purple-brown marginal spots; leaf sheaths tight and not inflated-tubular.
               37
Leaves typically many (3-14); 4-20 cm long; lip variously colored without conspicuous yellow disc; [widespread]
 ⇒ Epipactis
               37
Leaves typically fewer (2-5); 4-4.5 cm long; lip primarily white with conspicuous yellow disc; [s. FL]
 ⇒ Tropidia polystachya
          35
Leaves smooth, often creased at the midrib, but not plicate; lip not saccate.
             38
Leaves whorled, terminating the stem; [subfamily Vanilloideae; tribe Pogonieae]
 ⇒ Isotria
             38
Leaves alternate or opposite, not terminating the stem.
               39
Leaves 2, opposite, near the middle of the stem
 ⇒ Neottia
               39
Leaves (2-) 3-many, alternate, variously distributed on the stem.
                 40
Plant with aerial roots throughout stem; lip orange-red, deeply 3 to 4 lobed and marginally fimbriate; [subfamily Epidendroideae]
 ⇒ Epidendrum radicans
                 40
Plant without aerial roots throughout stem; lip variously colored, if orange then not deeply 3 to 4 lobed.
                   41
Lip without a spur; leaves 0.8-8.0 cm long.
                     42
Distal portion of lip not uniformly yellow; leaves ovate, 0.4-2.0 cm long
 ⇒ Triphora

(c) Gibson, Andrew Lane - CC-BY-NC, permission granted to NCBG
                     42
Distal portion of lip uniformly yellow; leaves linear or narrowly lanceolate, 1-8 cm long
 ⇒ Zeuxine strateumatica

(c) Marcum, Paul
                   41
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).
                     43
Leaves 5-40 cm long, sessile; plants from fleshy or fusiform roots.
                       44
Lip divided into 3 linear divisions, the divisions not further divided, fringed, or eroded
 ⇒ Habenaria
                       44
Lip not divided into 3 divisions, or divided into 3 divisions but the divisions not linear.
                          45
Spur elongate and slender, 4-50 mm long, the orifice larger
 ⇒ Platanthera
        34
Leaves basal (sometimes with bladeless sheaths upward on the stem).
             47
Lip oriented upward (not resupinate); flowers pink to white
 ⇒ Calopogon

(c) Griffith, Floyd A.
             47
Lip oriented downward (resupinate); flowers greenish, purplish-brown, maroon or yellowish.

(c) Cressler, Alan M.
               48
Sepals ascending or apically reflexed, not converging
 ⇒ Eulophia

(c) Cressler, Alan M.
          46
Leaves smooth, often creased at the midrib, but not plicate.
               50
Leaves long petiolate, not basally sheathing stems; sepals longer (to 30 mm), narrowly lanceolate
 ⇒ Eltroplectris calcarata
               50
Leaves not long petiolate, basally sheathing stems; sepals shorter, variously shaped
                 51
Flowers bicolored, the lip white, the sepals and petals pink; leaves 2
 ⇒ Galearis spectabilis
                 51
Flowers not bicolored, the lip, petals, and sepals similarly colored; leaves 2-5
                   52
Lip deeply divided into 3 linear segments; leaves 3-5
 ⇒ Habenaria
                 54
Inflorescence a raceme; lip with pink-purple coloration along margin; flowers larger, not tightly spiraling
 ⇒ Basiphyllaea corallicola
                 54
Inflorescence a spike; lip without pink/purple coloration along margin; flowers smaller, often spiraling or tightly assembled
 ⇒ Spiranthes
               53
Leaf blades more-or-less horizontally oriented, flat against the ground or 1-2 cm above it.
                 55
Flowers orange-red (except rarely light green as in S. lanceolata forma albidaviridis)
 ⇒ Sacoila
                 55
Flowers never strongly orange-red, instead white, yellowish, greenish, or brown (including coppery).
                   56
Lip oriented upward (flowers not resupinate).

(c) Ware, Richard & Teresa - CC-BY-NC, permission granted to NCBG
                     57
Lip without green spots (sometimes with green coloration but not green-spotted).
                       58
Large flowers distinctly pedicellate on racemes; lip short-caudate, 4.5-7 mm long; petals obliquely triangular
 ⇒ Ponthieva

(c) Cressler, Alan M.
                       58
Minute flowers sessile on spikes; lip apiculate, 1-2 mm long; petals narrowly obovate
 ⇒ Prescottia oligantha

(c) Hammer, Roger L.
                   56
Lip oriented downward (flowers resupinate).

(c) Ward, Scott G
                     59
Leaves with prominent white or pale green variegation on midrib and/or veins; [subtribe Goodyerinae]
 ⇒ Goodyera
                     59
Leaves without prominent variegation; [subtribe Spiranthinae].
                       60
Flowers white or green colored.
                          61
Lip and perianth segments each with a single central green stripe; leaves more or less fugacious
 ⇒ Beloglottis costaricensis
                          61
Lip and perianth without a central green stripe; occasionally with multiple green veins on the lip; leaf often persistent.
                            62
Flowers white, often also marked or veined with yellow or green; [widespread in our region]
 ⇒ Spiranthes
                            62
Flowers green, greenish-yellow, or bronze; [FL southwards]
                              63
Lip canaliculate (grooved longitudinally), without conspicuous yellow throat; flowers greenish-brown or coppery
 ⇒ Cyclopogon
                              63
Lip not grooved longitudinally, with conspicuous yellow throat; flowers greenish-white
 ⇒ Pelexia adnata