Uromyces appendiculatus var. crassitunicatus, var. nov. from Macroptilium atropurpureum

Abstract

Morphological studies on the rust fungi of Macroptilium, Phaseolus and Vigna show that three taxa can be distinguished. The Vigna rust, Uromyces vignae, is maintained as a species distinct from the bean rust, U. appendiculatus var. appendiculatus. A new variety, Uromyces appendiculatus (Pers.) Unger var. crassitunicatus J. Irwin, is described from Macroptilium atropurpureum. It differs from var. appendiculatus in having urediniospores with thicker side walls and more closely spaced echinulae. The teliospores are similar to those of var. appendiculatus, except that the side walls are thicker; the side walls are darker, with lineal rows of warts over the entire surface, and a conspicuous channel in the base; the hyaline apical thickening is thinner; and pedicels are more broadly attached.