Passing through California en route to Hawaii, I couldn’t resist delaying my departure – well, all right, any excuse would have done ! Yet this was an exceptionally good one. As soon as these two endangered orchids and I had been introduced, I just had to paint them. Both species can be found north of the San Francisco Bay, where their zones can overlap and they may still be found growing together amongst pines, other forests and slightly marshy habitats.- one orchid with its party atmosphere of wild joie de vivre, the other lower key yet very graceful. The naturally occurring white variety of Calypso bulbosa seems at home in damp, ferny territory. C. bulbosa can still be found at the southernmost part of its range on Mt.Tamalpais. Bulbosa refers to the corms at the base of plants. The genus Calypso was named after Homer’s sea nymph Calypso, meaning concealment, who delayed Odysseus on her island of Ogygia for seven years….
The pollinators painted here are a bee species and syphrid flies. Also included in the painting is the lovely butterfly Vanessa cardui – known by the name Painted Ladies. It is one of the most widely distributed species of butterfly, and can be found on all continents except Antarctica and Australia. Danaus plexippus ranges from N. and S. America and the Caribbean to Australia, New Zealand, the oceanic islands of the Pacific, Mauritius, and the Canary Islands.
Epipactis gigantea, whose local name is stream orchid, enjoys a wide distribution throughout western North America and elsewhere, and yet remains endangered in many places. E. gigantea can be confused with Epipactis helleborine, the similar yet only recently introduced European species which is, sadly, becoming somewhat rampant, almost invasive – though of course it is still a beautiful orchid. The elegant North American native painted here, Epipactis gigantea, though normally terrestrial, can be semi-epiphytic, growing in full sun or shade, drenched by ocean spray at sea level or clinging to steep mountainsides at nearly 3000 metres, even in deserts – as long as there’s a reliable root-level water source. But its favourite home is along stream banks. Periodic drought is currently the worst threat. Flowers can be seen from early March – September. Flies with eggs to lay somewhere nourishing are fatally attracted to this orchid’s promising aroma which resembles the honeydew smell given off by aphids. This “decoy” scent is a fooler as there will be no food for developing larvae. However, this strategy seems much more successful in terms of seed production than that of C. bulbosa. As a back up, E. gigantea can even self-pollinate [autogamy] through pollen falling onto the stigma.
Until fairly recently colonies of the exquisite Calypso bulbosa var occidentalis could be enjoyed flourishing in areas of high rainfall from sea level to 1800 metres – in mossy pockets amongst deciduous larch, tamarack, redwood forests and cedar swamps – without too much effort. This has now changed as C. bulbosa is at great risk from not only logging, and, being terrestrial, feral pigs, but also the orchid’s need for rotting bark and leaf litter means they can only grow for a few years in the same place, relying on successful pollination to set seed and colonize anew. An apparently rather inefficient pollination system only contributes to the problem.
C. bulbosa has an impressive array of inducements to attract young, gullible and naive bees – from strong perfume in newly opened flowers to extensions that look like nectar spurs but contain no nectar, to false “ hairs “ on the lip which could resemble pollen bearing anthers. Bombus queens and female Psithyrus – even hoverflies – are taken in. The poor bees are encouraged to hunt for the promised reward until, bodies bent at an uncomfortable angle, their only fur-less patch is forced into contact with the sticky viscidium. Bees, however, seem to be fast learners who rarely make the same mistake twice. Actual pollination and subsequent seeds set are therefore rather infrequent. But there are always new young bees ready to be fooled…….© Frances Livingstone 2018