Thursday, May 18: one more trip to Rachel Carson Conservation Park to find and photograph the elusive large twayblade. Thanks to detailed directions from a friend, I found a nice group of the plants, about half of which were in bloom.

Also know as purple twayblade, brown wide-lip orchid, and mauve sleekwort, Liparis liliifolia is one of our native orchids. The two large basal leaves stand a few inches tall, while the flowering stem (a raceme) stands up to about a foot tall and produces as many as thirty flowers.

The lowest flowers open first. A colony of large twayblade will bloom for about two to three weeks.

All orchid flowers have three sepals and three petals, although in some species these parts are so highly modified they may not be recognizable as such. In large twayblade, the lowest petal is modified into a wide labellum (lip); the two lateral petals are very narrow and droop down inconspicuously.

You can see the two lower sepals through the labellum, which is so thin it’s actually translucent.

Large twayblade can be found in the Mid-West, Mid-Atlantic, New England, and northernmost parts of the South. It’s threatened in Massachusetts and Vermont, and endangered in Connecticut, New York, and Rhode Island. In Maryland it’s listed as S2S3/state rare.

Look for it in rich, moist woodlands. It should still be blooming in the Maryland piedmont. The purple/brown colors of the petals and pedicels make for good camouflage against the leaf litter, but the distinctive pair of basal leaves stands out.

“Tway” is an obsolete word meaning “two”.