Monday, August 17, 2015

Twenty-fifth Orchid of the Season and Others


Listera (now Neottia) banksiana, also known as Listera caurina, is one of our most common orchids.  known as the Northwestern Twayblade, we see it most often in open forests and along trailsides, and that was where we found these examples in Olympic National Park.  At first glance it looks like the much rarer Listera convallarioides, but is easily distinguished from that species by the blackish markings on the top of the lip.  It grows to 30 cm tall, though these plants were all smaller and carries up to fifteen insect-like flowers.  The friend from Canada who I was with when I photographed these found several plants with a third leaf, a much rarer form of the species, fma. trifolia.

Listera banksiana






Listera banksiana fma. trifolia



The same day we found the Listeras we also found Platanthera dilatata var. leucostachys and Platanthera stricta, the Tall White Northern Bog Orchis and the Slender Bog Orchis.  These were growing on wet banks and in wet ditches along the roadside, exactly where one would expect to find them.  Though we found hundreds of the Listeras, these were very few in number, due I am sure to the hot dry summer we've had.  These were still in good conditions but there were far fewer of them than previous years and we found none of the hybrid between the two species, Platanthera xestesii, Estes Rein Orchis, but that may have been due to overly enthusiastic mowing of the roadsides by the Park Service.

Platanthera dilatata var. leucostachys







Realized as I prepared this post that I never photographed Platanthera stricta.

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