Flora of North America species comparison

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Platanthera brevifolia

Platanthera

platanthera de hoja corta, short-leaf bog-orchid, shortflower bog orchid

bog-orchid, fringe orchid, piperia, rein-orchid
Habit Plants 16–60 cm. Herbs, perennial, erect to somewhat decumbent, rather succulent.
Roots

fasciculate, both slender and tuberous, fleshy;

if tuberous, then lance-fusiform.
Stems

leafy or leafless, terete;

Leaves 1–several, strictly basal or gradually reduced to bracts toward inflorescence, conduplicate, ascending to spreading, bases sheathing stem.
Leaves

few, ascending-sheathing, little more than bracts, scarcely reduced distally;

bracts often lacking;

blade ovate to elliptic-ovate, 2.5–6 × 0.7–2 cm.

Inflorescences

solitary, terminal, lax to dense spikes.
Spikes

lax to rather dense.

Flowers

resupinate, not showy, green to yellowish green;

lateral sepals reflexed or sometimes spreading;

petals ovate- to lance-falcate, margins entire;

lip descending or reflexed, linear to linear-oblong or linear-lanceolate, 6–10(–14) mm, margins entire, often with series of low parallel ridges on adaxial surface;

spur cylindric or tapering toward apex, 9–20 mm, apex usually rather acute;

rostellum lobes somewhat divergent, directed forward, rounded-subangular, rather prominent;

pollinaria straight;

pollinia remaining enclosed in anther sacs;

viscidia orbiculate to broadly elliptic-oblong;

ovary rather slender to stout, mostly 6–12 mm.

few to many, usually resupinate (not resupinate in P. nivea), sometimes showy;

petals entire to fringed or emarginate;

lip lobed, 3-partite, spurred at base, margins entire to fringed;

pollinaria 2;

pollinia 2;

viscidia free;

stigma entire.
Fruits

capsules, ellipsoid to cylindric.

Platanthera brevifolia

Platanthera
Phenology Flowering Jul–Sep.
Habitat Dry to moist open, usually coniferous, forest, sometimes seasonally moist banks of intermittent streams
Elevation 2100–2750 m (6900–9000 ft)
Distribution
from FNA
NM; Mexico
[WildflowerSearch map]
[BONAP county map]
from USDA
Primarily north temperate (a few tropical)
[BONAP county map]
Discussion

The greatly reduced herbage of Platanthera brevifolia is distinctive. Robust plants may lack developed leaves altogether, with merely a few reduced bracts at the base of the stem and an inflorescence comprising nearly the entire height of the plant. A strong mycotrophic mode is suggested by the occurrence in some colonies of truly albino plants without pigmentation.

Platanthera brevifolia largely replaces P. sparsiflora in Mexico and is very distinctive at its northern limit in the United States. Although P. sparsiflora is exceedingly variable in floral dimensions, in habit, and in the number, size, and placement of leaves, the pattern seen in P. brevifolia seems to lie outside this range of variation. With a generally longer spur and very different ecologic requirements, it is here treated at the specific level. Nonetheless, P. brevifolia is reported to intergrade with P. sparsiflora in Mexico (R. McVaugh and W. R. Anderson. 1974+, vol. 16, pp. 254–256), yet the latter species probably does not range there beyond a possible occurrence in Baja California (M. A. Soto 1988). 

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species ca. 200 (32 species in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Lip lobed, fringed, eroded, lacerate, or emarginate.
→ 2
1. Lip entire, at most abruptly dilated toward base (in some robust Alaskan material of P. dilatata var. albiflora basal dilation of lip is elaborated forward, taking form of lateral lobules).
→ 15
2. Lip deeply and subequally 3-lobed (lateral lobes each in area equaling approximately 1/2 middle lobe, often much more).
→ 3
2. Lip not deeply, subequally 3-lobed, merely auriculate, fringed, eroded, lacerate, or emarginate, or apically shallowly 3-lobed.
→ 8
3. Petals linear-oblong to oblong-spatulate, usually entire; lip greenish white.
P. lacera
3. Petals oblong-obovate to flabellate, lacerate toward apex; lip pure white or pink-magenta to lavender.
→ 4
4. Lobes of lip dentate to dentate-lacerate, not fringed; rostellum lobes spreading.
P. peramoena
4. Lobes of lip fringed; rostellum lobes spreading or parallel.
→ 5
5. Flowers pink-magenta to lavender, rarely white; pollinia erect; pollinaria nearly straight; column appearing truncate in lateral view.
→ 6
5. Flowers white; pollinia directed forward; pollinaria geniculate; column appearing hooded in lateral view.
→ 7
6. Rostellum lobes spreading, angular in lateral view.
P. grandiflora
6. Rostellum lobes parallel, rounded in lateral view.
P. psycodes
7. Rostellum lobes spreading, angular in lateral view.
P. praeclara
7. Rostellum lobes parallel, rounded in lateral view.
P. leucophaea
8. Lip basally auriculate, or apically emarginate or shallowly lobed.
→ 9
8. Lip fringed or eroded.
→ 10
9. Lip with basal pair of auricules flanking prominent tubercle on adaxial surface, apex obtuse to emarginate.
P. flava
9. Lip without basal pair of auricles or tubercle, apex shallowly 3-lobed.
P. clavellata
10. Lip not conspicuously fringed, merely eroded to lacerate.
→ 11
10. Lip conspicuously fringed.
→ 12
11. Flowers white; lip 10–15 mm.
P. integrilabia
11. Flowers yellow to orange; lip less than 6 mm.
P. integra
12. Rostellum lobes triangular, apices directed forward (column appearing acute in lateral view).
→ 13
12. Rostellum lobes slender, directed downward toward apices (column appearing truncate in lateral view), straight to distally retrorse.
→ 14
13. Flowers white.
P. blephariglottis
13. Flowers orange.
P. ciliaris
14. Spur 8–17 mm, its mouth nearly circular; rostellum lobes strongly retrorsely curved toward apices; viscidia presented downward and approximately parallel to lip.
P. chapmanii
14. Spur 4–10 mm, its mouth triangular or keyhole-shaped; rostellum lobes scarcely to strongly curved; viscidia presented forward, nearly perpendicular to approximately parallel to lip.
P. cristata
15. Leaves 1–2; scape naked or with 1(–2, very rarely) bracts.
→ 16
15. Leaves (1–)3–several; scape with gradually reduced bracts distially.
→ 21
16. Spur saccate to stoutly cylindric; lip broadly elliptic-suborbiculate to obovate, concave.
P. chorisiana
16. Spur slender; lip linear to rhombic-lanceolate, ± flat.
→ 17
17. Leaf 1, or if 2 alternate and widely spaced on stem, erect-spreading.
→ 18
17. Leaves 2 in basal pair, wide-spreading, commonly lying on ground.
→ 19
18. Lip linear to linear-rhombic-lanceolate (lanceolate in subsp. oligantha); spur tapering from broad base, ± as long as lip; widespread.
P. obtusata
18. Lip elliptic to elliptic-oblong or elliptic-lanceolate; spur cylindric to clavate, ± 2 times as long as lip; w Aleutian Islands.
P. tipuloides
19. Scape naked; lip directed forward, lanceolate; spur tapering to apex from broad base.
P. hookeri
19. Scape with 1 or more bracts; lip pendent, linear to linear-oblong; spur clavate.
→ 20
20. Spur less than 28 mm; pollinaria less than 4.6 mm.
P. orbiculata
20. Spur equal to or greater than 28 mm; pollinaria equal to or greater than 4.6 mm.
P. macrophylla
21. Lip uppermost (flowers not resupinate); flowers white.
P. nivea
21. Lip lowermost (flowers resupinate); flowers white, green, or yellowish.
→ 22
22. Viscidia linear to linear-oblong; flowers white; lip usually with suborbiculate to orbiculate basal dilation.
P. dilatata
22. Viscidia oblong to orbiculate; flowers greenish, yellowish, or white; lip linear to linear-rhombic, elliptic, or lanceolate, base undilated or with obscure to orbiculate basal dilation.
→ 23
23. Column comparatively large, occupying ca. 2/3 hood formed by dorsal sepal and petals; rostellum lobes widely spaced, diverging, and together with stigma and connective forming hemispheric chamber; lip linear to linear-oblong or linear-lanceolate, or narrowly elliptic, base undilated.
→ 24
23. Column comparatively small, occupying less than 1/2 hood formed by dorsal sepal and petals; rostellum lobes parallel, diverging, or converging, but scarcely elevated, at most separated by narrow slit, not forming hemispheric chamber; lip linear to linear-lanceolate, rhombic-linear, rhombic-lanceolate, or elliptic, base undilated or with obscure to orbiculate basal dilation.
→ 26
24. Leaves reduced; blades rigidly erect, loosely sheathing stem, scarcely spreading beyond width of inflorescence, sometimes absent; dry to mesic forest.
P. brevifolia
24. Leaves well developed; blades prominent, spreading well beyond sheathing bases and width of inflorescence; wet-mesic to wet sites.
→ 25
25. Spur 6–14 mm, 0.7–1.6 times length of lip; lip with prominent basal median ridge; leaves ascending or wide-spreading, scattered along stem.
P. sparsiflora
25. Spur 12–17 mm, 1.3–2.6 times length of lip; lip without prominent median ridge, but often with series of obscure parallel ridges; leaves wide-spreading, usually limited to proximal portion of stem.
P. zothecina
26. Anther low, appearing to lie atop stigma; anther sacs widely diverging from apices scarcely separated by obscure connective; flowers autogamous; pollinia rotated forward, commonly free of anther sacs and/or fragmenting into loose masses that trail downward onto stigma; spur clavate, mostly slightly shorter than lip; lip rhombic-lanceolate, yellowish to yellowish green.
P. aquilonis
26. Anther high, rising above stigma; anther sacs more nearly parallel, converging, or diverging from apices separated by evident connective; flowers not autogamous (except evidently autogamous in P. hyperborea; see also note under P. huronensis); pollinia remaining within anther sacs; spur scrotiform or saccate to slenderly clavate or filiform, much shorter to much longer than lip; lip linear, elliptic, or broadly lanceolate, or with abrupt basal dilation, white to green or yellowish.
→ 27
27. Spur 8–25 mm, much longer than lip, filiform; lip usually with small median basal thickening, linear-oblong to linear-elliptic, rarely rhombic-ovate.
P. limosa
27. Spur 2–12 mm, much shorter to slightly longer than lip, saccate or scrotiform to capitate, clavate, or slenderly cylindric; lip linear-rhombic, linear-lanceolate, or rhombic-lanceolate, or with pronounced orbiculate to suborbiculate basal dilation.
→ 28
28. Pollinaria and rostellum lobes parallel to converging toward orbiculate viscidia; spur scrotiform or saccate to spatuloid-capitate or strongly clavate, much shorter than lip.
P. stricta
28. Pollinaria and rostellum lobes diverging toward oblong or sometimes (in P. purpurascens) orbiculate viscidia; spur slenderly cylindric to strongly clavate, saccate, or scrotiform, slightly longer to much shorter than lip.
→ 29
29. Lip oblong or rarely lanceolate, dull yellowish; rostellum lobes usually projecting forward, separated by narrow slit; leaves clustered toward base of stem.
P. sparsiflora
29. Lip broadest at base, lanceolate, ovate, or linear, or with pronounced basal dilation, white, greenish or yellowish; rostellum lobes low, not projecting forward; column without evident slit; leaves scattered along stem.
→ 30
30. Lip pure white, usually with pronounced suborbiculate to orbiculate basal dilation or rarely shallowly 3-lobed; spur clavate to slightly capitate, somewhat to very much shorter than lip.
P. dilatata
30. Lip greenish or yellowish, mostly lanceolate, ovate, or linear, sometimes obscurely or prominently dilated at base; spur slenderly cylindric to strongly clavate, saccate, or scrotiform, shorter than to slightly longer than lip.
→ 31
31. Spur saccate or scrotiform to clavate-inflated (widest at apex), ca. 1/2 length of lip; lip yellowish green to dull yellowish or intensely bluish green, sometimes marked with red, linear-lanceolate to prominently rounded-dilated at base; musty scented.
P. purpurascens
31. Spur slenderly cylindric to slenderly clavate or clavate, not inflated, merely obtuse to subacute, shorter to slighter longer than lip; lip whitish green to perhaps yellowish green in P. hyperborea; sweet scented.
→ 32
32. Lip linear-rhombic, with straight sides, not at all rounded-dilated at base; spur ca. 2/3 to slightly shorter than lip; Aleutian Islands, adjacent Alaska.
P. convallariifolia
32. Lip lanceolate to ovate, usually obscurely to prominently rounded-dilated at base; spur slightly shorter to slightly longer than lip.
→ 33
33. Lip lanceolate, usually obscurely rounded-dilated at base, whitish green; spur slenderly clavate to slenderly cylindric; flowers not autogamous; pollinia retained within anther sacs (but see note); viscidia oblong; widespread.
P. huronensis
33. Lip ovate, rarely lanceolate, abruptly and broadly dilated at base, apparently yellowish green; spur markedly clavate; flowers autogamous; pollinia rotating forward and downward from anther sacs or fragmenting and pollen masses trailing onto stigma; viscidia linear to linear-oblong; Greenland.
P. hyperborea
Source FNA vol. 26. FNA vol. 26, p. 551. Author: Charles J. Sheviak.
Parent taxa Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae
Sibling taxa
P. aquilonis, P. blephariglottis, P. chapmanii, P. chorisiana, P. ciliaris, P. clavellata, P. convallariifolia, P. cristata, P. dilatata, P. flava, P. grandiflora, P. hookeri, P. huronensis, P. hyperborea, P. integra, P. integrilabia, P. lacera, P. leucophaea, P. limosa, P. macrophylla, P. nivea, P. obtusata, P. orbiculata, P. peramoena, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
Subordinate taxa
P. aquilonis, P. blephariglottis, P. brevifolia, P. chapmanii, P. chorisiana, P. ciliaris, P. clavellata, P. convallariifolia, P. cristata, P. dilatata, P. flava, P. grandiflora, P. hookeri, P. huronensis, P. hyperborea, P. integra, P. integrilabia, P. lacera, P. leucophaea, P. limosa, P. macrophylla, P. nivea, P. obtusata, P. orbiculata, P. peramoena, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
Synonyms Habenaria brevifolia, Habenaria sparsiflora var. brevifolia, Limnorchis brevifolia, P. sparsiflora var. brevifolia
Name authority (Greene) Kraenzlin: Orchid. Gen. Sp. 1: 639. (1899) Richard: De Orchid. Eur., 20, 26, 35. (1817)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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