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greater roundleaf orchid, large round-leaf orchid, large-leaf bog-orchid

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

Habit Plants 23–63 cm. Plants 16–60 cm.
Leaves

2, in subequal basal pair lying on ground;

bracts (very rarely, 0–)1–6, scattered along stem;

blade broadly elliptic, orbiculate, or oblate, 7–24 × 5–19 cm.

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.

Spikes

lax.

lax to rather dense.

Flowers

resupinate, rather showy;

calyx mostly greenish white;

corolla mostly white;

lateral sepals reflexed to somewhat spreading;

petals lanceolate-falcate, margins entire;

lip descending to somewhat reflexed, linear-oblong to linear-lanceolate, without basal thickening, 10–23 × 1–2.5 mm, margins entire;

spur slenderly clavate, 28–46 mm;

rostellum lobes directed strongly forward, wide-spreading, angular;

pollinaria nearly straight, (4.6–)4.7–6.8 mm;

pollinia remaining enclosed in anther sacs;

viscidia orbiculate;

ovary slender to rather stout, mostly 16–29 mm.

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.

Platanthera macrophylla

Platanthera brevifolia

Phenology Flowering Jun–Aug. Flowering Jul–Sep.
Habitat Mesic to wet coniferous and deciduous forest Dry to moist open, usually coniferous, forest, sometimes seasonally moist banks of intermittent streams
Elevation mostly 0–1000 m (mostly 0–3300 ft) 2100–2750 m (6900–9000 ft)
Distribution
from FNA
CT; MA; ME; MI; MN; NH; NY; PA; VT; NB; NL; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
NM; Mexico
[WildflowerSearch map]
[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.)

Source FNA vol. 26. FNA vol. 26.
Parent taxa Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera Orchidaceae > subfam. Orchidoideae > tribe Orchideae > subtribe Orchidinae > Platanthera
Sibling 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. nivea, P. obtusata, P. orbiculata, P. peramoena, P. praeclara, P. psycodes, P. purpurascens, P. sparsiflora, P. stricta, P. tipuloides, P. zothecina
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
Synonyms Habenaria macrophylla, P. orbiculata var. macrophylla Habenaria brevifolia, Habenaria sparsiflora var. brevifolia, Limnorchis brevifolia, P. sparsiflora var. brevifolia
Name authority (Goldie) P. M. Brown: Wild Fl. Notes 3: 23. (1988) (Greene) Kraenzlin: Orchid. Gen. Sp. 1: 639. (1899)
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