Washington's native orchids - Washington Native Orchid Society

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Garfield Grant Grays Harbor Island Jefferson King Kitsap Kittitas Klickitat Lewis Lincoln Mason Okanogan Pacific Pend Oreille n n n n n n n n n n n n n n n n n n n n n n 25 n n n n n n n n n n 9 n n n n n n n n n n n n n n n n n n n n n n n n 30 n n n n n n n n n n n n n n n n n n 18 n n n n n n n n n n n n n n n 17 n n n n n n n n 10 n n n n n n n 9 n n n n n n n n n n n 14 n n n 4 n 1 n n n n n n n n n n n n n 18 n n n n n n n n n n n n n n n n n n n n n n n 26 n n 2 n n n n n 5 n n n n n n n n n n n n n n n n n n n n n 24 n n n n n n n n n n n n n n n n n n 18 n n n n n n n n n n n n n n n n n n 19 n n 2 n n n n n n n n n n n n n n n n n n n n n n 20 n n n n n n n n 8 n 1 n n n n n n 6 n n n n n n n n n n n n n n n n n n n n n 22 n n n n n n n n n n 12 n n 2 n n n n n n n n n n n n n n n n n n n n n n n 28 n n n 4 n n n n n n n n n 9 n n n n 4 n n n n n n n n n n n n n n n n n n n n n n 26 n 2 n n n n n n 7 n n n n n n n n n n n n n n n n n n n n n n 26 5 1 9 9 7 21 6 15 23 9 1 7 22 8 18 18 16 17 20 12 13 14 14 3 11 21 7 17 Pierce WINTER 2008 www.MasterGardenerOnline.com • MASTERGARDENER • PAGE 39 San Juan Skagit Skamania Snohomish Spokane Stevens Thurston Wahkiakum Walla Walla Whatcom Whitman Yakima Total Counties
Why does this phenomenon occur in so many terrestrial orchid species, including many Washington State natives? The answer is probably associated with the deep forest environments in which these species are found (Leake, 1994). Low light levels, combined with thick litter layers, To view more photos of these native species, visit the various excellent Web sites listed on opposite page. are ideal conditions for fungal growth but difficult for small plants with p h o t o s y n t h e t i c r e q u i r e m e n t s . Mycoheterotrophy enables orchids to survive indefinitely in the shade by reducing or abandoning photosynthesis, and instead harnessing diverse fungal species to supply needed resources. As a group, terrestrial orchids do not transplant well and are difficult to grow from seed. These difficulties arise from the intricate relationship between the orchid and its possible fungal and plant partners, as well as the narrowly specific environmental conditions many orchids require. This is especially true of mycoheterotrophic species. Artificial growing conditions can rarely duplicate those in nature, and the additional use of fertilizers and fungicides can harm mycorrhizal fungi and doom orchid survival. Obviously, a diverse and healthy fungal community is an absolute requirement for terrestrial orchids to thrive. Future of terrestrial orchids? Orchids often have complex relationships with specific pollinators: if the pollinators disappear, then so does that orchid population’s ability to set seed. There is no question that ecosystem destruction and pesticide overuse threaten these and many other species. However, the tenacity of terrestrial orchid populations has been largely overlooked. Koopowitz (2001) states, “If anything should happen to the natural pollinators, the affected orchids are also doomed.” This is not quite accurate, as successful pollination is not a requirement for vegetative survival. And, apparently, established terrestrial orchid populations can survive a very long time. There was a fascinating study of a population of pink lady’s slipper orchids (Cyprepedium acaule) in Virginia. For many years, researchers had been documenting the life history of this temperate, terrestrial orchid population. This species relies on bee pollinators to sexually reproduce, and early in the study, the Virginia population showed signs of reproductive failure as few bees ventured into the shaded deciduous forest where the study was being conducted. During the study, however, the forest was attacked by gypsy moths and severely defoliated. The increase in sunlight reaching the forest floor had multiple effects on C. acaule, including stimulation of seed germination, improved pollination from increased bumblebee activity, and increased fruit production (Gill, 1996). Incredibly, further historical investigation of this population revealed that in all likelihood it has existed for centuries and could be considered functionally immortal. Forest disturbances, such as fire, insect defoliation, and clearing by settlers, all benefit this orchid species and others that require some exposure to full sun to thrive. Thus, this population had existed in “suspended animation,” waiting for appropriate environmental conditions to resume flowering and setting seed. Native terrestrials Following is a quick synopsis of our local species. 1 Many of the white-flowering species are pollinated by nocturnal insects, and their fragrances are more intense in the evening. (See table on pages 38-39 for county locations.) • Calypso bulbosa var. occidentalis (Western fairy slipper). Named for the beautiful sea nymph who captured Odysseus in Greek mythology, likewise the calypso orchid captivates us with its striking pink color and resemblance to a tiny shoe. Calypso orchids are widepspread throughout Washington State, nestled in dark forests with deep humus layers. Like several other deep forest orchids, the species is mycoheterotrophic. 2 • Cephalanthera austiniae (phantom orchid). As its name suggests, this pure white plant 3 emerges from the humus like a tiny ghost on dark forest floors. Chlorophyll is completely absent in this mycoheterotrophic species, which receives all of its nutrition from its fungal partner. • Corallorhiza maculata, including varieties maculata, occidentalis, and ozettensis (summer coralroot). For our purposes, it’s easiest to consider this species as a single unit, as there is disagreement as to whether the reported varieties are distinct subpopulations or merely representative of a morphologically diverse species. This widely distributed, mycoheterotrophic species occurs in deep woods with rich humus, often growing in large clusters. Summer 1 This list is constantly changing; in the short period of time between when I began researching this subject and reviewing the final draft, three other orchids were designated as Washington State natives. They are Cypripedium x columbianum, thought to be a cross between C. montanum and C. parviflorum; Platanthera x correllii, thought to be a cross between P. hyperborea and P. stricta; and P. gracilis, the lax-flowered green orchid. No official county information is available as of this writing—but it may be by the time you read this article. PAGE 40 • MASTERGARDENER • www.MasterGardenerOnline.com WINTER 2008 1 Melissa Rathbun-Holstein Melissa Rathbun-Holstein Melissa Rathbun-Holstein
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Page 7: • Piperia species are found throu

Washington's native orchids - Washington Native Orchid Society

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