Cronartiaceae - Photographs of members of this family of heteroecious rusts which have two alternating hosts, typically a pine and a flowering plant. Rust - Information from Wikipedia on the Uredinales, plant parasites which mainly cause foliar infections. Puccinia graminis - Microscopic image. Puccinia graminis - Microscopic image. Puccinia graminis - Microscopic image. Puccinia graminis - Microscopic image. Puccinia graminis - Microscopic image of this species on a Berberis leaf. Gymnosporangium juniperi-virginianae - An illustrated article by Tom Volk on this rust fungus which is parasitic on the eastern red cedar and the apple tree, alternating between these two hosts. Puccinia - Two magnified images of the fruiting bodies of Puccinia species which grow as parasites on foliage. Phleogena faginea - Several enlarged photographs of these minute fungi. Coleosporium tussilaginis (a rust fungus) - Photographs of this species, some enlarged, growing on the underside of leaves and magnified images of the uredospores. Puccinia antirrhini (Snapdragon Rust) - Several photographs of this species which infects antirrhinums, and microscopic images of the uredospores. Cumminsiella mirabilissima - Many photographs, some enlarged or magnified, of this rust fungus. Pucciniaceae - Photographs of several species of Puccinia, Uromyces pisi-sativi and Uromyces dactylidis. Milesina dieteliana - Photographs of this rust fungus which infects ferns, and magnified images of the uredospores. Gymnosporangium juniperi-virginianae - Spermogonia of this species that causes cedar-apple rust on the upper side of an apple leaf and aecia of the fungus on the lower side. Puccinia coronata - Image of teliospores. Gymnosporangium clavipes - Information on this pathogen which alternates between two host species, and photograph of it erupting from infected cedar tissue after rain. Miyagia pseudosphaeria - Microscopic image showing the cross section of a uredinium. Phakopsora pachyrhizi - Microscopic image showing an appressorium arising from a germinating urediniospore. Puccinia graminis - Image showing the two-celled teliospores of this species which causes stem rust of wheat. Puccinia melanocephala - Image of the urediniospores.