SPERMOGONIA in small conglomerations on the upper and under leaf surfaces, 75-115 µm diam.
Peridium cup-shaped, 0.2-0.5 mm diam, with a yellowish edge.
Peridial cells loosely connected, rounded when seen in a transverse section, with an outer wall slightly thickened, up to 6-8 µm, ornamented with fine dots, and an inner wall, 1-1.5 µm thick, covered with small warts.
AECIOSPORES globose, irregularly ellipsoid, slightly angular, 16-23 x 15-20 µm.
Wall colourless, thin, densely covered with very fine warts, rarely with larger warts and falling off tubercles, up to 3 µm diam.
UREDINIA (u) occur on the under leaf surface, angular or irregularly prolate, surrounded with remnants of rent epidermis, yellow brown, dusty, up to 1.0 mm diam. On the upper leaf surface, directly above the uredinia, first purple, later dark violet, small spots appear.
UREDINIOSPORES (ue) globose to longitudinally ellipsoidal and clavate, tapering towards the base, 25-40 x 15-23 µm, with a more or less distinct pedicel.
Wall yellow brown, 2-3 µm thick, densely ornamented with warts spaced ca. 1 µm apart.
Germ pores (gp) 4, equatorial, with large, flattened papillae (pl).
TELIA do not form in Poland.
TELIOSPORES (te) form singly in uredinia, ellipsoidal, 1-2-celled, rounded at both tips, constricted at the transverse septum, 28-33 x 21-26 µm.
Wall yellow brown, up to 3 µm thick in the upper spore part, tapering towards the spore base, evenly covered with small warts spaced ca. 2 µm apart.
Germ pores 2 in each cell, usually located oppositely, rarely only one top pore present in the upper spore cell, all without a distinct papilla.
Pedicel (p) colourless, straight or curved, up to 165 µm long.
PLANT HOST AND DISTRIBUTION. In Europe, spermogonia, aecia, uredinia, and telia of C. mirabilissima occur on Mahonia aquifolium (Push) Nutt. In North America, all the structures are also produced on some other plant species of the genus Mahonia Nutt. (Majewski 1979).
NOTES. Cumminsiella mirabilissima is the only species of the genus so far found in Poland.
The fungus can be damaging to nursery plants (Smith et al. 1988).
Majewski T. 1979. Grzyby (Mycota) XI. Podstawczaki (Basidiomycetes), Rdzawnikowce (Uredinales) II. Warszawa-Kraków, 462 pp.
Smith I. M., Dunez J., Lelliott R. A., Phillips D. H., Archer S. A. 1988. European handbook of plant diseases. Blackwell Scientific Publications.