2016 Native Orchid Conference field trips — Malaxis porphyrea and Platanthera limosa — 2016-07-31 through 2016-08-05

The third and fourth native orchid species that we were introduced to at the 2016 Native Orchid Conference symposium in Arizona are Malaxis porphyrea or Purple Malaxis orchid and Platanthera limosa or Thurber’s Bog orchid. They could not be any more different in appearance from each other, as you will soon discover.

Malaxis porphyrea: As is typical of most of our Malaxis species, it has a single, clasping leaf and a non-branching stem. The species name, porphyrea, is the Greek word, porphyra, the purple-fish or the dye that was made from it. The tiny purple flowers circle the flower stem from about halfway up the stem to the apex. There may be as many as 100 flowers per plant. The small size of the flowers, the tendency for the plant to sway in even the slightest breeze, and the 3-dimensional aspect of the inflorescence makes it quite challenging to photograph. Here is an image of one of the larger plants we found, coming in at about 12 inches (30 cm):

Malaxis porphyrea
Malaxis porphyrea

Platanthera limosa: This species is a tall one, similar to other green-flowered Platanthera orchids. The species name, limosa, is a Latin word for “muddy” — describing the type of habitat in which the plants can usually be found. The plants we saw were about 3-4 feet (1-1.2 meters) tall and were part of a dense population of plants growing on a muddy slope. The plants were quite robust, having as many as 200 flowers on each stem. Its nectar spur is relatively long in comparison with other green Platanthera species of similar size and shape. Here is an image of a portion of the inflorescence of one of the plants I was able to isolate from the group:

Platanthera limosa
Platanthera limosa

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The Malaxis porphyrea plants we found were growing in the shade of Pinus ponderosa or Ponderosa Pine and Picea engelmannii or Englemann Spruce in the sky islands of the Chiricahua Mountains in Cochise County, Arizona. Both of the large tree species are common at the 9,000-foot (2750-meter) altitude where the orchids thrive. The Malaxis porphyrea plants were seen growing in close association with another Malaxis orchid species, Malaxis abieticola or Arizona Adder’s-mouth orchid, which was mentioned in a previous blog post.

Our first encounter with this unusual orchid species was on one of the scheduled field trips, but it was abruptly ended by a drenching thunderstorm. When we descended the mountain and returned to our vehicle, we decided that we would return to that same location on the day after the symposium ended. Walter Ezell and I had planned a couple of extra days after the symposium in the case that we wanted to visit some different orchid locations on our own. Fortunately, the day started out clear and cool. As I mentioned in the previous blog post, it ended quite differently.

Some of the following images were taken in the rain, while others were taken on our second visit:

Malaxis porphyrea Malaxis porphyrea

A couple of things to note here. The plant on the above left was growing where it received more sunlight while the plant on the above right was growing in dense shade. Apparently, plants in receiving more sunlight produce a more crowded inflorescence. Also note the tiny wasp pollinator on the stem of the plant on the left. Here is a close-up version of that image. Check out the pollinium on the head of the wasp:

Malaxis porphyrea with a wasp pollinator

Following are full plant images of a couple of the several dozen plants we saw:

Malaxis porphyrea Malaxis porphyrea

Additional plant images of Malaxis porphyrea:

Malaxis porphyrea Malaxis porphyrea
Malaxis porphyrea Malaxis porphyrea

Malaxis porphyrea

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On our scheduled field trip to the Santa Catalina Mountains, in Pima County just north of Tucson, we ended up on Mount Lemmon at about 8,500 feet (2,600 meters) in elevation. The last site we visited was a habitat for Platanthera limosa or Thurber’s Bog orchid. We had to cut our visit short because of the unrelenting rain — typical, as we found out, for the monsoon season in southern Arizona. We couldn’t be too upset with the weather, because after all, it’s the monsoon rain that brings out the area’s native orchids.

I think that everyone involved, including the field trip planners, were surprised to find such a robust population of this orchid species. Here is a shot of the dense growth of these tall, green orchids:

Dense group of Platanthera limosa

The area of the densest plant growth was about 15 feet by 8 feet (4.5 meters by 2.4 meters), and it was full of blooming plants! I managed to isolate a few plants in order to get some close-up images:

Platanthera limosa Platanthera limosa

Upon closer inspection, it was apparent that a few of the plants had been in bloom for some time, because those were already forming seed capsules. Like several of the tall, green Platanthera species, this one may be self-pollinating, resulting in every flower forming a seed capsule. In the case of the self-pollinating Platanthera species, the pollen grains are slowly ejected from the anther sacs and fall down onto the stigma resulting in pollination. However, this species has been known to be pollinated by bees, moths, and butterflies — leading to the prospect of greater chances for successful pollination. In any case, here are two images of plants in the population that were forming seed capsules:

Platanthera limosa Platanthera limosa

What a great end to another successful Native Orchid Conference symposium. Although we were able to see several different orchid species, many of them rare and new to the attendees, a large part of the draw of the symposium is getting together with other like-minded orchid enthusiasts as well as seeing old friends and meeting new people. The programs presented during the symposium were top-notch, as we were treated to many fine photographic images and discussions of the current state of native orchid research and discovery. If you, dear reader, are interested in learning more about this organization (and I strongly suggest that you do so), please go to the NOC website. There, you will find information about the organization, a gallery of North American native orchids, as well as a membership application form. I hope to see you at a future NOC symposium.

-Jim

4 comments


  • John Fowler

    I’m glad you had such a successful and worthwhile trip.

    August 10, 2016
  • sonnia hill

    This is a beautiful Malaxis orchid. Love the color.

    That Platanthera limosa stand is impressive.

    August 10, 2016
  • Tom Mirenda

    Another outstanding post…..starting to feel very sad I wasn’t at this NOC meeting!

    August 10, 2016
  • Fantastic shots which I guess were not easy. But a triumph !

    August 10, 2016

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