Jones Cycladenia

At the time of its listing as a threatened species, Jones cycladenia (Cycladenia humilis var. jonesii) occurred in four known areas in the Canyonlands region of southwestern Utah and northern Arizona. The populations were disjunct, occurring at least 100 miles apart. It was estimated that 7,500 individual plants existed, but since many of the shoots belong to the same plant, this estimate may be too high. Jones cycladenia has exacting soil requirements, growing only on the gypsiferous, saline soils of the Cutler, Summerville, and Chinle formations. It occurs in plant communities of mixed desert scrub, juniper, or wild buckwheat and Mormon tea at elevations from 1340 to 1830 m (4390 to 6000 ft).

Description

Jones cycladenia is a long-lived, perennial herb that grows four to six inches tall. Its hairless stems are covered with a white, waxy coating, and its leaves are bright-green, rounded, and somewhat succulent. Pink, woolly-haired flowers, shaped like trumpets, bloom between mid-April and early June. The fruits are brown follicles, which are dry fruits that open along one side at maturity. Although Jones cycladenia can reproduce by seed, it does not produce many fruits or seeds, and its pollinators have either disappeared, appear only episodically, or may be migratory. Therefore, Jones cycladenia primarily grows clonal shoots from its rhizomes (horizontal, underground stems).

The U.S. Fish and Wildlife Service has listed Jones cycladenia as a threatened species since May 5, 1986. In Utah, it is listed as imperiled, and in Arizona, it is listed as critically imperiled.

Jones cycladenia is threatened by off-road vehicles, exploration for oil, gas, and minerals, and livestock grazing. In addition, because it may be a relict from the Tertiary period, Jones cycladenia may be poorly adapted to the present climate and is threatened by future climate change. The ecosystem where the plant grows is thought to be fragile, easily degraded, and slow to recover. No critical habitat was designated for this species, because of the fear that naming the location of the plants would attract collectors.

Related species

The genus Cycladenia consists of only one species, Cycladenia humilis, which has three varieties. The other two varieties occur in California (var. humilis and var. venusta). Cycladenia’s closest relative is thought to be Mandevilla, a neotropical genus.

References

NatureServe. 2009. Cycladenia humilis var. jonesii. NatureServe Explorer: An online encyclopedia of life. Version 7.1. NatureServe, Arlington, Virginia. Available at http://www.natureserve.org/ explorer/ (accessed 21 May 2010).

U.S. Fish and Wildlife Service. 1986. Rule to determine Cycladenia humilis var. jonesii (Jones cycladenia) to be a threatened species with critical habitat. Federal Register 51(86): 16526-16530.

U.S. Fish and Wildlife Service. 2008. Recovery outline for the Jones cycladenia (Cycladenia humilis var. jonesii). Available at http://ecos.fws.gov/docs/recovery_ plan/Jones%20cycladenia_123008.pdf (accessed 21 May 2010).

Prepared by Kelly Reeves, Southern Colorado Plateau Network Inventory and Monitoring Program, 2010.

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