SPERMOGONIA (s) 80 to 130 diam, occur in small conglomerations on both the upper and under leaf surface.
Peridium cup-shaped, 0.3-0.5 mm diam, with a yellowish, rugged edge.
Peridial cells with an outer wall, 6-8 µm thick, ornamented with fine warts and an inner wall, 3-5 µm thick, covered with larger warts.
AECIOSPORES (ae) subglobose, prolate to irregularly prolate, 18-30 x 15-24 µm.
Wall colourless or yellowish, 1-2 µm thick, densely covered with fine warts.
UREDINIA (u) mainly occur on the upper leaf surface, elliptical, up to 0.6(-1.0) mm long, dusty, orange yellow.
Wall yellowish, 1.5-2.0 µm thick, ornamented with spines spaced 2-3 µm apart.
Germ pores 8-11(-14), indistinct, irregularly distributed.
TELIA (t) on the under leaf surface, rarely on leaf sheaths, prolate, up to 1 mm long, black, frequently connected to form circular to elliptical conglomerations.
TELIOSPORES (te) clavate, cylindrical or elliptical, 35-70 x 14-23 µm.
Wall smooth, brown yellow, up to 2 µm thick when examined from a side, darker-coloured, with digitate processes of a different shape, up to 10 µm long at the top.
Germ pores indistinct.
Pedicel yellowish, thin-walled, persistent.
PLANT HOST AND DISTRIBUTION. Spermogonia and aecia of P. coronata occur on Rhamnus catharticus L. and Frangula alnus Mill. (Majewski 1979). Uredinia and telia form on Avena sativa L. and numerous other genera and species of the family Poaceae.
NOTES. Puccinia coronata causes crown rust of oats.
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.