UREDINIA (u) on both leaf surfaces, but usually more abundant on the upper leaf surface, small, elliptical, first covered with epidermis, later opened, yellowish, dusty, usually placed in long strips between leaf veins.
UREDINIOSPORES (us) widely elliptical to egg-shaped, 22-30 x 19-25 µm.
Wall colourless, rarely yellowish, up to 1.5 µm thick, covered with small spines spaced 1.5-2.5 µm apart.
Germ pores 9-19, indistinct, distributed on the whole spore surface.
TELIA (t) on the under leaf surface, rarely on the upper, small, roundish or prolate, up to 0.5 mm long, covered with epidermis, black, frequently connected with some neighbouring ones.
TELIOSPORES (te) irregularly clavate or cylindrical, asymmetrically flattened or sharpened at the top, slightly narrowed at the lateral wall, 30-45(-70) x 15-23 µm.
Wall smooth, yellowish in the lower teliospore part, thin, becoming brown and thicker, up to 3-6 µm, towards the top.
Germ pores indistinct.
Pedicel yellowish, with a brown, thickened up to 2-5 µm wall at spore base, persistent.
PLANT HOST AND DISTRIBUTION. Uredinia and telia of P. striiformis occur on many plant species of different genera of the family Poaceae (Majewski 1979).
NOTES. Puccinia striiformis is the causal agent of yellow rust of wheat, barley, and rye (Agrios 1988).
Agrios G. N. 1988. Plant pathology, 3rd edition, Academic Press, INC. San Diego, New York, Berkeley, Boston, London, Sydney, Tokyo, Toronto.
Majewski T. 1979. Grzyby (Mycota) XI. Podstawczaki (Basidiomycetes), Rdzawnikowce (Uredinales) II. Warszawa-Kraków, 462 pp.