Platanthera aquilonis (Green Bog Orchid) - photos and description






Anther sacs spread apart at base and touch or nearly touch near their tip


General: Stout-stemmed orchid having a dense spike with many flowers.  Foliage yellow-green in colour. Plant glabrous.

This plant is very similar to Platanthera huronensis.

Flowers: Flowers grow in a loose to dense spike, flowers number 10-50 in a spike.  We measured a spike at 13 cm long. Flowers yellow-green with a long lower lip, the lateral petals and dorsal sepal forming a hood over the column, the lateral sepals are spreading. We measured a flower at 1 cm long, and lip at 5 mm long. Lower lip is blunt-tipped, entire. Flowers with no scent.

Leaves: Leaves are oval to oblanceolate, clasp the stem, alternate. We measured at 16 cm long and 4 cm wide (pressed flat).

Height: Listed in Budd's Flora to 60 cm, we measured plants to 39 cm tall.

Habitat: Bogs, and wet meadows, ditches, might be the most common orchid in the southern half of the province.

Abundance: Common.

Origin: Native.

Synonyms: Listed in some of the field guides we use as: Habenaria hyperborea.

Similar species: Very closely resembles Platanthera huronensis which is new to the province and to date been found in a few locations in Saskatchewan. To distinguish between the two species, you need to examine the flowers carefully with a loupe. The anther sacs of P. aquilonis converge / touch near their apex (as shown above), and are spread apart at their base. While those of P. huronensis are more or less parallel to one another and separate at their apex.

Other differences:

- P. huronensis is whitish-green in colour, P. aquilonis is yellowish-green in colour, side by side comparison below but note I don't think you can always count on seeing this much of a difference.

P. huronensis on the left, P. aquilonis on the right

- The flowers of P. huronensis are scented, in my experience this can be noticed only occasionally, the flowers of P. aquilonis in Saskatchewan are never scented,

- P. huronensis has occasional very robust specimens, P. aquilonis never has these very robust specimens.

- FNA lists longer flower lips and spurs in P. huronensis, which makes sense because it's a tetraploid. However there is overlap in these measurements between the two species:

  Lip:  P. huronensis 5-12 mm long;   P. aquilonis 2.5-6 mm long
  Spur: P. huronensis 4-12 mm long;   P. aquilonis 2-5 mm long.

   Genus Platanthera described in FNA.

- I have read websites describe small differences between the shapes of the base of the flower lips, and differences in the shape of each species flower spurs, but I haven't been able to see a consistent difference between the two plants regarding these characteristics.

When and where photographed: Photographed these plants June 24th and June 27th in saline, wet prairie near our home in Regina, Saskatchewan, and June 27th in a forest marsh in the Cypress Hills about 400 km southwest of our home in Regina, SK.