Puccinia areolata, P. treleasiana, and P. gemellaon Marshmarigold ( Calthaspp.) in subalpine habitats in Northwestern United States.

[摘要] Marshmarigolds ( Calthaspp.) are members of the buttercup family (Ranunculaceae) and inhabit the Cascade and Rocky Mountains in western North America. Several rust species infectCalthaspecies, but onlyPuccinia areolata, Puccinia treleasiana , andPuccinia gemellahave been reported in the Pacific Northwest. Observations were made on rust incidence and severity onCalthaspp. in July through September between 2001 and 2013 in subalpine regions of Colorado, Idaho, Montana, Utah, Washington and Wyoming. Leaves, petioles and flower stalks with rust pustules were examined and the host species identified using morphological characteristics. Plants collected in ID, WA, and MT were identified asCaltha leptosepala  ssp.howelli(synCaltha biflora ) and plants in WY, CO, and UT were identified asCaltha leptosepalassp.leptosepala . Foci of infection were typically solitary leaves, individual plants or small clusters of infected plants although a 90% incidence of infected rust plants was observed in a 10 m diameter area with no visually distinct foci in WA in 2013.Puccinia areolatawas the only rust observed in Washington,Puccinia gemellawas observed in Idaho, andPuccinia treleasianawas observed in Montana and Wyoming. Collections made possible direct comparisons among the three rust species.

[学科分类] 植物学

[关键词] Caltha;Puccinia areolata;Puccinia treleasiana;Puccinia gemella;Uredinales;subalpine ecology;diseases of native plants