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1984) SHEVIAK: SPIR.ANTHES 13
<br /> They are membranaceous in moistened material. but commonly show a limited
<br /> thickening in the center. Venation is predominantly parallel, but with a variable
<br /> elaboration of branched, divaricaling veins in the basal half. The expression of
<br /> each of these lip characters varies. but taken together, the combination of shape,
<br /> fleshiness, and venation clearly establishes a condition intermediate between the
<br /> lips of S. nlagnicampoi um and S. rmnaraoRmra.
<br /> Despite variation in individual characters, the aspect of the plant as a whole is
<br /> distinctive. The leafy, sometimes cespitose growth with long stems supporting
<br /> ascending, slender (lowers with variably free sepals is characteristic.
<br /> A Note on Rarity
<br /> Spiranthes diluvialis is presently known to have been collected at only ten sites,
<br /> and some of these support scarcely more than subpopulations. Of the stations
<br /> which can be located rather precisely, at least three seem no longer to support the
<br /> species. The modern station in Salt Lake City has been destroyed (Lois Arnow,
<br /> pers. comm.). I was unable to locate the species at the stations in Tooele and
<br /> Utah counties; the former is now heavily grazed and the habitat severely altered,
<br /> and the second seems to have been inundated by the recent rise in the level of
<br /> Utah Lake. The apparent rarity of the plant may arouse interest in possible
<br /> endangered or threatened status. Large areas of apparently suitable habitat occur,
<br /> however, and the species should be actively sought. Some literature reports of
<br /> Spiranrhes from relatively low elevations may refer to this species, but not all
<br /> vouchers have yet been located. Due to the complexity of the group, a significant
<br /> number of specimens may be misdetermined and the stations consequently un-
<br /> detected.
<br /> Ackno»ledgments
<br /> I wish to thank the curators and staffs of the herbaria that lent specimens for
<br /> this study, including ARIZ, BRY, COLO, CS, DAV, JEPS, MICH. MO. MSC,
<br /> NTS, NY, OGDF, UC, US, UT, WANF. I am indebted to a number of people
<br /> for the provision of invaluable information, photographs, drawings, and live
<br /> plants. Special thanks are due Stephen Blecher. Littleton, Colorado: Marie Anita
<br /> Burling.McNeal,Arizona;Dr.William Gambill,Denver Botanic Gardens: Lucian
<br /> Long. Colorado Springs, Colorado; Dr. Timothy McCabe, New York State Mu-
<br /> seum: Karen Miles. Golden. Colorado;James Pynynski. Bellevue. Nebraska; and
<br /> Dr. Thomas Todsen, Las Cruces, New Mexico. William Jennings, Boulder. Col-
<br /> orado, has provided a wealth of information and coordinated much of the flow
<br /> of information between East and West. Dr. Paul Catling. Agriculture Canada, has
<br /> conducted preliminary statistical analyses which contributed to the conclusions
<br /> presented here and has provided important ideas and criticisms during the study.
<br /> Dr. Norton Miller, New York State Museum, reviewed an early manuscript and
<br /> made valuable comments.
<br /> This studv has been supported in part through grants from the Denver Botanic
<br /> Gardens and the American Orchid Society Fund for Education and Research.
<br /> Additionally, many of the persons cited above incurred significant personal ex-
<br /> penses in providing assistance, and their contributions are deeply appreciated.
<br /> Literature Cited
<br /> Ames.O. 1905. A synopsis of the genus.SPtranthr,5 north of Mexico.Orchidaceae.fast. 1: 122-156.
<br /> Calling. P. NJ. 1980. Systematics of Spiraniltes L.C.Richard in northeastern North America. Ph.D.
<br /> Thesis. University of Toronto.
<br /> 1982. Breeding systems of northeastern North American Spvnnthes(Orchiciaceae).Canad.
<br /> J. Bot. 60: 3017-3039.
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