Twenty-third Orchid of the Season

This is the smallest of the Platanthera/Piperias that grow in our area, the plants usually 20-45 cm, with many flowers closely packed on the stems.  Piperia transversa, the Flat-spurred Piperia, has been reclassified as a Platanthera transversa, but I have not yet gotten used to the new names.  From a distance the flowers appear to be cream-colored, but close-up they are white and green and are readily distinguished from the other Piperias by the spur which is held at a ninety degree angle to the stem.  The bloom season for this species is slightly later than that of Platanthera elegans and slightly earlier than that of Platanthera elongata, but it is possible to find all three species in bloom at the same time, as I did when these photos were taken in the area of Deception Pass on Whidbey Island.  There were not, however, as many of them this year as previous years, probably on account of the hot dry summer.

Platanthera natual hybrid (?)

While looking for and photographing different Platanthera/Piperia species, I found this oddity which appears to be a natural hybrid between Platanthera transversa, the Flat-spurred Piperia, and Platanthera elegans, the Elegant Piperia, or instead of the latter species, Platanthera elongata, the Long-spurred Piperia.  If it is not a natural hybrid the only other possibility is that it is an odd, short-spurred form of Platanthera transversa.  All three of these species grow in the location I was visiting, though Platanthera elegans only on the other side of the hill where this was found.  The flowers are colored like the flowers of Platanthera transversa, but the spur is not the long, horizontal spur of that species.  The spur looks like that of Platanthera elegans or Platanthera elongata, both of which curve downward, but it is much shorter than the spur of Platanthera elongata.  The plant was growing with other plants of Platanthera transversa.  I've included photos of the three species found in the area for comparison.

July 25

(Whidbey Island)

Piperia transversa

Piperia elegans

Piperia elongata

Platanthera transversa

Washington has five species of Platanthera that weere formerly classified as Piperia, and this is the smallest of the five, not taller than 30 cm and with 2 cm flowers (including the long spur).  It is known as the Flat-spurred Piperia, not for the shape of the spur but because it is parallel to the flower stem.  It is supposed to be fragrant at night but I have never tested that.  When it blooms the leaves have usually withered away and so all one sees is the bare flower spike with its blooms.  It likes drier areas in full or part sun.

June 23

(Columbia River Gorge)

July 25

(Whidbey Island)

Washington's Five Piperias

Here in the Pacific Northwest and up into Canada there are five Piperia species, though two others have been reported periodically from Washington and Oregon, but without verification.  The Piperias have been separated from the genera Habenaria and Platanthera (more recently they have been recombined with Platanthera).  They share a tuber-like root, very slender spikes and flowers with similar-looking lips and petals.  The leaves of all these species almost always wither around the time of flowering, so that the flower spikes appear as leafless stems.  The two unverified species are Piperia leptopetala, the Lace Orchid, and Piperia michaelii, Michael's Piperia.  The five species known to grow in our area are as follows:

Platanthera (Piperia) unalascensis, the Alaskan Piperia.
This is the most common of the five Piperias and has the widest range, growing from Alaska south to California and east across southern Canada and the northern United States into the Great Lakes region.  It is also, in my opinion, the least attractive of the five species, with small green or greenish-yellow flowers.  It can grow in large clumps and to a height of over 80 cm, and the flowers, though numerous are less than 1 cm in size and have a tiny spur that is barely visible.

 

There is a dwarf form of this species, forma olympica, that grows only in one location in the Olympic Mountains (these last two pictures show this form).

Platanthera ephemerantha (Piperia candida), the Slender White Piperia.
Piperia candida has been recently separated from Piperia unalascensis and the flower color is the most obvious difference.  Its flowers are white instead of green, though there are also differences in the shape of the spur and in the fact that this species has a day-time though faint fragrance.  In plant size, flower count, bloom time and habitat it is is like the Alaskan Piperia, but in our experience is somewhat more rare than its green cousin.

Platanthera (Piperia) elegans, the Elegant Piperia.
The Elegant Piperia is rightly named and the most attractive of the five species.  The plants can be very large, over 80 cm with numerous, tightly packed flowers that are somewhat larger than those of the previous two species, but still smaller than 1 cm.  It, too, has a faint fragrance but a much longer spur, that is nearly 1 cm.  Is is quite easily identifiable and cannot really be mistaken for any of the other species.  The tall plants with their white, long-spurred flowers are distinctive

Platanthera (Piperia) elongata, the Long-spurred Piperia.
This and the following species are quite easily confused.  In plant size, number of flowers, size of flowers and length of spurs they are very similar.  The plants are 60 cm or less and they have numerous flowers more or less crowded on the stems.  This species, however, has flowers that are dark green with a spur that curves downward, often paralleling the stem.  The flowers, though small and less than 1 cm in size are quite attractive with their long, 1.5 cm spurs.

Platanthera (Piperia) transversa, the Flat-spurred Piperia.
The Flat-spurred Piperia is named not for the shape of of the spur but for its position, one of the distinguishing characteristics.  The flowers are the same size as Piperia elongata and the spurs the same length, but the spur is held horizontally and in some cases even curves upward a bit.  That and the white flowers with a green or yellowish green mid-vein to each of the segments separates this from the Long-spurred Piperia.

Flat-spurred Piperia and Giant Rattlesnake Orchis in Washington Park

On August 13th I made an excursion first to Washington Park on Fidalgo Island and then to Goose Rock on Whidbey Island.  Both places can be reached by auto and are less than 30 minutes' drive from each other.  On this occasion I went alone since my wife, who usually accompanies me was busy with other things.

I went to Washington Park to see the Flat-Spurred Piperia, Platanthera transversa, in bloom.  It is, or was, the best location I knew for this native species (I found many more of them at Goose Rock).  They grow in some abundance along one of the trails on the south side of the park in a dry, mossy area.

They are not large plants, and by the time the flowers are open the leaves are withered, so it is easy to miss them, but up close the flowers are intricate and beautiful.  We found them first because we saw their leaves while looking for Fairy Slippers in the same area earlier in the season.

The name, "Flat-Spurred Piperia," refers not to the shape of the spur, but to its position, which is one of the distinguishing features of the species.  The nearly transparent spur (the picture shows it with the nectar clearly visible), stands at a nearly horizontal position and at a ninety degree angle to the flower stalk.

I also found a quite a few of the Giant Rattlesnake Orchis, Goodyera oblongifolia and took a few pictures of the beautifully patterned leaves.  This species comes in two forms, a plain-leaved form and a form with silver veining, fma. reticulata.  The flowers are the same in both forms.