Aerial reproductive structures of vascular plants as a microhabitat for myxomycetes

Abstract

This study explored the occurrence and distribution of myxomycete species on the aerial reproductive structures of vascular plants. Eight species of vascular plants representing five families were sampled. The doubled rope climbing method was used to collect bark and cones from the canopy of Pinus echinata. Bark and aerial seed pods were gathered from Cercis canadensis, follicles and stems from Asclepias syriaca, dried composite inflorescences and stems from Echinacea angustifolia, E. pallida, and E. paradoxa var. paradoxa, and capsules and stems from Yucca glauca and Y. smalliana. Reproductive structures and bark/stems for 202 host plants were separated and cultured in 541 moist chambers, resulting in 118 collections yielding 32 myxomycete species representing 11 genera, seven families and five orders. There was no significant difference in pH values of the reproductive structures and bark/stems of the host plants, however legume pods of C. canadensis (6.9 ± 1.3) had higher pH than the bark (6.0 ± 1.1) and had a different composition of myxomycete species. Myxomycete orders have optimal pH ranges. Nonmetric multidimensional scaling, multiresponse permutation procedure and indicator species analysis showed a significant difference in species richness of reproductive structures and bark/stems. The bark of trees had greater mean species richness of myxomycetes than the reproductive structures, but the reproductive structures of herbaceous plants had greater mean species richness of myxomycetes than the stems. A new term, herbicolous myxomycetes, is proposed for a group of myxomycetes frequently associated with herbaceous, perennial, grassland plants. An undescribed species of Arcyria occurred only on cones of P. echinata.

• Asclepias syriaca
• Cercis canadensis
• Echinacea angustifolia
• E. pallida
• E. paradoxa var. paradoxa
• herbicolous myxomycetes
• pH
• Pinus echinata
• Yucca glauca
• Y. smalliana

This paper reflects the work of the first author on her master’s thesis, accepted by the University of Central Missouri Graduate School, May 2008. Sincere thanks to Lisa Schmidt for arranging and perfecting the color images for thisPUBLICation. Prof. Stephen W. Wilson reviewed the original thesis. Sydney E. Everhart, Bill Hickman and Angela R. Scarborough climbed P. echinata trees to help collect samples. Everhart reviewed thisPUBLICation. Kenneth L. Snell served as climbing instructor and patiently helped CMK, SEE and ARS gain confidence as climbers and in the reliability of the climbing equipment. We also acknowledge everyone who helped in the field by housing us and/or providing expertise on where to collect as well as granting permission to collect in state parks and conservation areas. These gracious individuals include Reid and Carolyn Franks, Frank and Merilyn Griffith, Wes Jackson (The Land Institute), Jeanie Hilten and Keith Langdon and Discover Life in America at Great Smoky Mountains National Park, Tim Smith at Missouri Department of Conservation, Paul Super at Appalachian Highlands Science Learning Center at Purchase Knob GSMNP, David Taylor of the U.S. Department of Agriculture in Daniel Boone National Forest and everyone at the Berea College school of Forestry. Photo credits: CMK Figs. 1b, h, k, l; HWK Figs. 1a, c, f, j; Christopher D. Crabtree Fig. 1i; Glenda Carmack Figs. 1d–e; Craig Freeman Fig. 1g. This project was financially supported by the National Science Foundation Division of Environmental Biology Award 0343447, Discover Life in America Award 2001–26 and 2002–17 and National Geographic Society Committee for Research and Exploration Award 7272-02.