Puccinia convolvuli

A parasitic fungus developing on living leaves of Calystegia sepium or Convolvulus sepium, with all developmental stages on the same host (spermogonia, aecia, uredinia, telia, and basidia); the present study corresponds to the initial or aecial stage of the species, causing yellowish to reddish spots on the upper leaf surface, with aecia on the underside.

Aecia cup-shaped, 0.5 to 0.7 mm in diameter, with a raised, lacerate, whitish margin and yellowish interior, arranged in rings or circles in clusters of 10 to 15 specimens, reaching a cluster diameter of 3 to 5 mm.

Peridial wall of aecia formed by angular hyphae compressed together, polygonal to rhomboidal, 20 to 30 µm long, 15 to 25 µm wide, with a thick, striate outer wall, and an inner verrucose core with dense uniform warts.

Aeciospores subglobose, broadly ellipsoidal to slightly angular, fairly thin-walled (only 1 to 1.5 µm thick), yellowish under the microscope, 19 to 27 µm long, 16 to 21 µm wide, with bright yellowish to orange granular content inside.