Platanthera blephariglottis
Platanthera orbiculata
white fringe orchid, white-fringe bog-orchid
large round-leaf orchid, large round-leaf rein orchid, lesser roundleaf orchid, round-leaf bog-orchid, round-leaf orchid
2–several, spreading to ascending, scattered along stem, rather abruptly to gradually reduced distally;
blade linear-lanceolate, ovate-lanceolate, elliptic-lanceolate, 5–35 × 1–5 cm.
2, in subequal basal pair lying on ground;
bracts (very rarely, 0–)1–6, scattered along stem;
blade broadly elliptic to orbiculate or oblate, 5–21 × 3–22 cm.
dense to rather lax.
lax to dense.
resupinate, showy, white;
lateral sepals reflexed;
petals linear to oblanceolate, apex fringed to nearly entire;
lip reflexed to porrect, without basal thickening, ovate-oblong to oblong-elliptic, rarely quadrangular-suborbiculate, margin fringed;
spur essentially cylindric, slender;
rostellum lobes curving forward, slightly spreading, angular-elongate;
pollinaria with stalks curved forward;
pollinia remaining enclosed in anther sacs;
viscidia elliptic-suborbiculate to orbiculate;
ovary slender, 10–28 mm.
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, 7–17 × 1–2.5 mm, margins entire;
spur slenderly clavate, 14–27 mm;
rostellum lobes directed strongly forward, wide-spreading, angular;
pollinaria nearly straight, 3–4.5(–4.8, very rarely) mm;
pollinia remaining enclosed in anther sacs;
viscidia orbiculate;
ovary slender to rather stout, mostly 10–26 mm.
= 42.
Platanthera blephariglottis
Platanthera orbiculata
Varieties 2 (2 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The key will permit determination of most specimens of Platanthera orbiculata and P. macrophylla. More precise discrimination of ambiguous specimens is possible by use of the formula from A. H. Reddoch and J. M. Reddoch (1993): spur length + (2 × pollinarium length), which for P. orbiculata is less than 38 and for P. macrophylla is equal to or greater than 38.
Considerable variation in size and shape of leaves occurs, and although to some extent regional in nature, intergradation is complete; recognition of infraspecific taxa is unwarranted. A few collections from isolated areas on the Pacific Coast of Canada are noteworthy, however. Those are small, few-flowered plants with rather narrow leaves borne alternately or suboppositely toward the base of the stem, as in some Asiatic species. They are in some respects very similar to Platanthera freynii Kränzlin, an Asiatic species distinguished primarily by its abruptly narrowed petals, in contrast to the generally broader, but variable, petals in North American plants. These western plants warrant further study to establish their identity and to elucidate relationships between North American and Asiatic species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Spur less than 26 mm, to 1.25 times length of ovary. | var. blephariglottis |
1. Spur at least 30 mm, commonly about 2 times length of ovary. | var. conspicua |
- Local floras:
BC, 
WA - Local Web sites:
Flora NW, 
Go Botany, 
IL Wildflowers, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
