from the the July 12, 2009 Newsletter, issued from the Siskiyou Mountains west of Grants Pass, Oregon:
FLAT SPURRED PIPERIA
Last month I introduced you to the Western Lady's Tresses orchid, Spiranthes porrifolia, growing in dry soil here, especially at woods edges. Now those plants have vanished and a new, considerably more common orchid species is taking their place in similar habitats. At first glance the two species are very similar -- just a slender spike of tiny, greenish- white flowers -- but closer examination shows that the flowers are very different. You might enjoy comparing the Western Lady's Tresses seen earlier, still online at http://www.backyardnature.net/n/h/spiranth.htm with what's flowering now, shown above.

The new orchid often is called the Royal Rein or Flat-Spurred Orchid. It's PIPERIA TRANSVERSA*, distributed from British Columbia south through our area into California. Orchids in the genus Piperia are known as "rein orchids," and Flora of North America lists ten species, though none appear in Weakley's Flora of the Carolinas, which covers most of the US Southeast. Piperia seems to be a northern and western genus, and this is the first time I've run across it.

The Royal Rein Orchid keys out easily because its flowers bear long, straight, usually ± horizontal spurs, like those of larkspurs, nasturtiums and violets. In the picture you can see that the spur is much longer than the corolla itself. Other Piperias bear spurs but they're shorter and/or not horizontal.