Puccinia buxi

On living leaves of boxwood (Buxus sempervirens), with pustule-like protuberances 1 to 2 mm in diameter, reddish brown to black, usually appearing on the underside of the leaf, producing yellowish-reddish spots on the upper surface. A species that completes its entire life cycle on the same host, lacking an aecial stage, with only the telial stage in which the teliospores produce metabasidia, which in turn produce basidiospores.

Mature telia black, with ellipsoidal to fusiform, two-celled teliospores with a strong constriction at the central septum, brown under the microscope, very thick-walled (wall thickness 2 to 4 µm), 60 to 95 µm long, 20 to 30 µm wide, with dense granular content of small yellowish-brown oil droplets inside, with a long hyaline pedicel up to 150 µm long and up to 3 µm wide.

Herbarium material available: JTP2209/24.