Pucciniastrum goodyerae  

A rust on leaves of the orchid Goodyera repens (“creeping lady's-tresses”), visible as orange pustules on both sides of leaves.

Uredosori amphigenous, scattered or crowded in small groups, subepidermal, minute, round, 0.1-0.3 mm. across, orange-yellow, then pale yellow, long-covered by the epidermis, peridia hemispherical, delicate, firm, dehiscent by an apical pore, peridial cells small, isodiametrically to irregularly polygonal, 7.5-15 µm across, lateral ones radially elongate, walls of the peridial cells thin, smooth, colourless or subhyaline, ostiolar cells rather large, 32-43 µm high, finely echinulate above; uredospores ovoid, 23-34 x 16-20 µm, wall finely echinulate, uniformly thick, 1.5-2 µm thick, colourless, contents pale yellow. Spermogonia, aecidia and teliosori unknown.

Description adapted from Wilson, M., & Henderson, D. M. (1966). British rust fungi.

Map of known distribution in Great Britain and Ireland.