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Volume 81—2001

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New Locations of Cuscuta cuspidata Engelm. (Cuscutaceae) in Oklahoma

Richard G. Ruth

Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803

Thomas J. Tauer

Department of Biology, Coe College, Cedar Rapids, IA 52402

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The genus Cuscuta (common dodder) consists of achlorophyllous, holoparasitic flowering plants that bear haustoria and lack roots (1). Haustoria develop when the early vegetative form of Cuscuta establishes contact with a suitable host species. After establishing a parasitic relationship with its host, Cuscuta loses contact with the soil (2, 3). Some species of the genus are quite host-specific, whereas others have been known to grow more vigorously when grown in the presence of mixed host species (4-7).

Members of Cuscuta have a growing season that typically begins in May, when the seeds germinate and establish contact with a nearby host. If the parasite does not find a host within 10-15 d after germination, it withers and dies (2, 3). After Cuscuta successfully parasitizes a host plant, haustoria allow nutrient extraction and provide the food for vegetative growth, which can become quite extensive. Plants can begin to flower as early as June and produce mature seeds into November (1).

We report four new locations for Cuscuta cuspidata Engelm. in Oklahoma (Table 1). The site south of Cache is the first documented location of the species in Comanche County. Specimens were collected and preserved using standard plant pressing procedures, and deposited in the Cameron University Herbarium. They were dentified using a key by Waterfall (8) and their identification verified by Ronald J. Tyrl. These four new locations indicate that C. cuspidata is more widespread in the state than previously recorded. Thirty-nine other sites for the species appear in the Oklahoma Biological Survey/OK Natural Heritage database (9).



We thank Ronald J. Tyrl, for his help in confirming the identity of specimens collected from all four sites, and the two anonymous reviewers for their helpful comments and editing. Financial support was provided by the Beta Beta Beta Honor Society, Academic Research Center, and Mary Dixie Mullin Endowed Chair of Cameron University.


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1.   Diggs GM Jr, Lipscomb BL, OíKennon RJ. Illustrated flora of north central Texas. Fort Worth (TX): Botanical Research Institute of Texas; 1999.

2.   Prather LA. The biology of Cuscuta attenuata Waterfall [MS thesis]. Stillwater (OK): Oklahoma State University; 1990. 123 p. Available from: OSU Library.

3.   Prather LA, Tyrl RJ. The biology of

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Cuscuta attenuata Waterfall (Cuscu-taceae). Proc Okla Acad Sci 1993;73:7-13.

4.   Kelly CK, Horning K. Acquisition order and resource value in Cuscuta attenuata. Proc Natl Acad Sci 1999; 96:13219-13222.

5.   Gaertner EE. Studies of seed germination, seed identification, and host relationships in dodders, Cuscuta spp. Cornell Univ Mem 1950;294:1-56.

6.   Verdcourt B. Biological flora of the British Isles. Cuscuta L. J Ecol 1948;36:356-365.

7.   Yuncker TG. Revision of the North American and West Indian species of Cuscuta. Biol Monogr 1920;6:1-41.

8.   Waterfall UT. Keys to the flora of Oklahoma. 4th ed. Stillwater (OK): Published by author; 1969.

9.   Hoagland B. An electronic catalog and atlas of the flora of Oklahoma. Norman (OK): Oklahoma Biological Survey/Oklahoma Natural Heritage Program; July 2000.

Received: October 1, 2000; Accepted: April 5, 2001