Species of the genus Phragmidium (Pucciniales) as parasites of brambles (Rubus: Rosaceae) in Ukraine

Four species of the genus Phragmidium that parasitize plants of the genus Rubus in Ukraine are reported. Of them, Phragmidium acuminatum has not been recorded for more than 90 years, since its last report in 1933. This species is a specialized parasite of the stone bramble (Rubus saxatilis), which according to modern views belongs to Rubus subg. Melanobatus. Three other species are widespread in Ukraine. Phragmidium rubi-idaei parasitizes raspberries (Rubus idaeus) of the subgenus Idaeobatus. Phragmidium bulbosum and P. violaceum infect representatives of Rubus subg. Rubus and can both parasitize plants of the same species. In Ukraine, both species were observed on Rubus caesius, R. candicans, R. canescens and R. hirtus. However, they clearly differ in morphological features: most teliospores of Phragmidium violaceum are 4-celled with an apical hemispherical papilla up to 5 µm high, while in P. bulbosum teliospores are mostly 4–8-celled with an apical cylindrical or conical papilla up to 12 µm high. The previously reported twisting of the upper part of the teliospore pedicel in species of the genus Phragmidium parasitizing species of the genus Rosa was also observed in P. bulbosum, P. rubi-idaei and P. violaceum. The article is illustrated with photomicrographs obtained using a scanning electron microscope.