New records of Uromyces erythronii (Pucciniales) from Ukraine

Specimens of the rust fungus Uromyces erythronii were recorded on Erythronium dens-canis, a rare species listed in the Red Data Book of Ukraine, in April 2016 near Chemeryntsi village (Lviv Region, Ukraine) and in May 2016 near Zaluzhne village (Zhytomyr Region, Ukraine). An investigation of the Erythronium specimens deposited in the herbaria of vascular plants of Lviv Natural History Museum (LWS) and M.G. Kholodny Institute of Botany (KW) revealed four more samples of this fungus. A list of all localities in which U. erythronii was recorded in Ukraine is provided. The article is illustrated by micrographs obtained by scanning electron microscopy.


Introduction
The genus Erythronium L. comprises about 30 species of spring-flowering perennial plants distributed in temperate regions of the Northern Hemisphere.It was established that the genus is probably sister to Amana Honda and that Tulipa L. is sister to the clade of Erythronium and Amana (Clennett et al., 2012).Within Erythronium, there are three strongly supported geographically distinct clades occurring in Eurasia, western North America, and eastern North America (Allen et al., 2003;Clennett et al., 2012).Its centre of diversity lies in Oregon and northern California (Allen et al., 2003).The geographic distribution of the only European species E. dens-canis L. is highly disjunct.There are several fragmented areas, clearly separated from one another: north-eastern Portugal, northern Spain and the Pyrenees, the Massif Central and the western Alps, northern Italy, Hungary and the Balkans to northern Greece (Kleih, 2010).Isolated populations north of the Alps are located in the Czech Republic, Slovakia (Fischer et al., 2008), and Ukraine (Chervona knyha..., 2009).
Uromyces erythronii (DC.)Pass.parasitizes Eurasian species of Erythronium.In Japan and China it was also recorded on representatives of Amana (Hiratsuka et al., 1992;Teng, 1996), which is in concordance with the modern status of Amana as a genus separate from Tulipa and closely related to Erythronium.It should be noted that rusts of the genus Uromyces (Link) Unger do not occur on plants of the genus Tulipa.The earlier mentions of this fungus in Ukraine (Zerova et al., 1971;Tykhonenko, 1999)  Spermogonia on both sides of leaves, honeycoloured, solitary or mixed with the aecia, more or less conical.Aecia mostly hypophyllous, although they may appear on the petioles, in oblong or orbicular groups on yellow spots, generally quite conspicuous, peridium 0.3-0.4mm in diameter, at first covered by the epidermis but later cup-shaped with coarsely incised and outwardly turned margin (Figure, a).Peridial cells are of variable shape, generally pentagonal, rhomboid or almost square, outer wall almost smooth, inner is covered with warts.Aeciospores globose, polygonal or ellipsoidal, 20-30 × 15-24 μm, densely and finely verruculose (Figure, b, c), with a yellow-orange content.Telia on both sides of leaves in groups, rounded or elongated, 0.3-1 mm long, pulverulant (Figure , d The aim of this publication is to report new records of U. erythronii made in Ukraine in 2016 as well as those identified from the previously collected herbarium specimens of its host plant.

Materials and Methods
Specimens collected in the field were labelled and dried for further treatment.Aeciospores and teliospores mounted in water and/or lactic acid were investigated by light microscopy under Primo Star microscope and AxioVision 4.7 software, used as well for measurements of microstructures.For scanning electron microscopy samples were coated with an ultrathin coating of gold by ion beam sputtering unit JFC-1100.Images were obtained by scanning electron microscope JEOL JSM-6060 LA.Analysis of general distribution is based on the data from many bibliographic sources, and databases available through the Internet.
The specimens are deposited in the Mycological Herbarium of M.G.Kholodny Institute of Botany, National Academy of Sciences of Ukraine (KW) and in the herbarium of the Institute of Ecology of the Carpathians, National Academy of Sciences of Ukraine (LWKS).

Results and Discussion
The rust fungus Uromyces erythronii was recorded on Erythronium dens-canis, a rare species listed in the Red Data Book of Ukraine.Specimens were collected in April 2016 near Chemeryntsi village (Lviv Region, Ukraine) and in May 2016 near Zaluzhne village (Zhytomyr Region, Ukraine).Subsequent investigation of the Erythronium specimens stored in the herbaria of vascular plants of Lviv Natural History Museum (LWS) and M.G.Kholodny Institute of Botany (KW) revealed four more samples of this fungus.The synonymic names, description of spermogonial, aecial and telial stages, and data on distribution in Ukraine of this species are provided below.Original illustrations are followed by information on its morphology, general distribution and phenology.