Gymnosporangium spp., ornamentation of lateral walls of peridial cells of aecia. a. G. clavariiforme; b. G. sabinae; c. G. confusum; d. G. tremelloides; e. G. cornutum. In a and b with roundish papilla-like warts of different size; in c, d and e with elongate ridges of different size and density, but rather coarse in d; (a–e from Klebahn 1914: 646, 666, d as G. ariae-tremelloides, e as G. (aucupariae-)juniperinum).