First report of Uromyces acuminatus on Honckenya peploides, the endangered seabeach sandwort.

Honckenya peploides (L.) Ehrh. (Caryophyllaceae), commonly known as seabeach sandwort, is a species of special concern in Connecticut (4). Nearly an entire population of H. peploides in New London County, CT was found to be severely infected by the aecial stage of a rust fungus in June of 2008. Representative plants in the population were infected with aecia on more than 50% of the leaves. Aecia were amphigenous, gregarious, cupulate, pulverulent, yellowish, and erumpent with a hyaline to whitish peridium having a lacerate, somewhat recurved margin. Peridial cells were rhomboidal, 26 to 31 × 25 to 29 μm, smooth to finely verrucose. Aeciospores were globose to ellipsoid, 23.5 to 29 × 20.5 to 22 μm, hyaline to pale yellowish with a verrucose surface and hyaline walls 1.5 to 2 μm thick. Morphological characters corresponded to a reference specimen (BPI 000105) of the aecial stage of Uromyces acuminatus Arthur from Nova Scotia, as well as published descriptions (1,2). Subsequently, telia of U. acuminatus were...