Some interesting species of the genus Ascochyta

The paper presents eleven species of Ascochyta recently collected in central and southern part of Poland. Two of them, Ascochyta bondarceviana Melnik and Ascochyta equiseti (Desm.) Grove noted in Poland for the first time, are illustrated with microphotographs. In addition, nine other species are newly reported on their host plants species in the country. Short characteristics of the fungi species based on the collected specimens and the distribution maps of all fungi taxa are presented.


INTRODUCTION
The genus Ascochyta, one of the largest (over 1 400 names) and the most important genera of anamorphic fungi, was often examined since its description by Libert in 1830.As a result, many species were reallocated to other genera at the beginning of 20 th century, and some of them (e.g., Ascochytella Tassi and Ascochytula Died.) were later re-synonymized with Ascochyta (Buchanan 1987).The great interest in this genus stems from the fact that its members are the parasites of numerous cultivated and wild plants, causing diseases of economically important taxa (Melnik 2000).

MATERIAL AND METHODS
The analysed material has been collected mostly as a result of the systematic studies of plant parasitic micromycetes carried out in urbicoenoses of the Łódź city (Połeć 2010).The fresh specimens mounted in Lactophenol Picric acid Solution (Fluka) were examined using the microscopes Nikon Eclipse E200 and Nikon Eclipse 50i; measurements of the morphological structures were made also in tap water.Microphotographs of morphological structures of the species new for Polish mycobiota were taken with a Nikon DS-F1 digital camera.
The base for identification of host plants and fungi were the keys by Szafer, Kulczyński and Pawłowski (1986) and Rutkowski (2004), and taxonomic monographs by Melnik (2000) and Sałata (2002), respectively.The nomenclature of fungi taxa is given after Mułenko and Kozłowska (2008) while the nomenclature of hosts follows checklist by Mirek et al. (2002).
Available literature data were analysed and the distribution maps of all the species listed were prepared.The vouchers representing current collections are deposited in the Herbarium Universitatis Lodziensis (LOD) in the series of parasitic fungi labeled as PF.

RESULTS
As a result of the studies, eleven interesting species of the genus Ascochyta were identified, including two taxa new for Polish mycobiota, namely Ascochyta bon darceviana Melnik (on Ribes sp.) and A. equiseti (Desm.)Grove (on Equisetum arvense L.), both belonging to the subgenus Ascochyta.Nine other species are noted for the first time on host plant in Poland: Ascochyta daturae Sacc., A. doronici Allesch., A. euphrasiae Oudem., A. infuscans Ellis & Everh., A. lamiorum Sacc., A. leonuri Ellis & Dearn., A. sodalis Naumov, A. sonchi (Sacc.)Grove and A. verbascina Thüm.These are classified by Melnik (2000) in the Ascochyta subgenus Libertia Melnik, characterized by consistently single, central or sometimes displaced septum.The majority of the hosts are wild plants, three species are cultivated and one, Galinsoga parviflora Cav., is an alien and expansive element in European flora (DAISIE).
notes.The species has been recorded on dead and dying leaves and stems of Equisetum spp.from North America (USA) and many European countries (Melnik 2000;Farr et al. 2011).Although the species was expected by Sałata (2002), it has not been observed in Poland yet.
According to the data of Melnik (2000) pycnidia are up to 200.0 μm in diam.and conidia measure 7.0-12.0(-13.5)x 3.0-4.0,while according to the descriptions given ranunculoides L. in Bohukały near Bug river valley (Danilkiewicz 1990; Sałata 2002) (Fig. 3).Anemone sylvestris L. is a new host species for the fungus in Poland.
It is reported on Plantago intermedia Gilib.for the first time.However, as P. intermedia was previously included in Plantago major L. as subspecies intermedia (DC.)Arcang., thus some of the records of Ascochyta sodalis on P. major may, in fact, concern P. intermedia.

FINAL REMARKS
Although the genus Ascochyta has been monographed in Poland quite recently (Sałata 2002), 60 new species for Poland were reported within the following years (Mułenko, Kozłowska 2008;Wołczańska 2010).The recent finding of eleven interesting species of this genus, including two new for Poland, also proves that further investigations in natural and anthropogenic habitats are needed.
The taxonomy of Ascochyta species changes in time.According to Punithalingam (1988) 1-septate conidia are the norm for the genus Ascochyta.However, the occurrence of a small percentage of unicellular and 2-septate conidia is possible and it does not exclude the species from the genus.The subgenus Ascochyta is characterized with the admixture of 3-4-celled conidia (Melnik 2000).In the opinion of Boerema et al. (2004) mature conidia of true Ascochyta species are almost always septate and their conidiogenesis differs from the one observed in Phoma species.The conidia of Phoma taxa are always unicellular when released, but some of them can become two-or more-celled by secondary septation.
According to Boerema et al. (2004) many taxa referred to as Ascochyta species are, in fact, the members of Phoma genus.This concerns some of the species presented in the current report: Ascochyta leonuri (= A. nepetae) is a synonym of Phoma nepeticola (Melnik) Dorenb.& Gruyter as well as Ascochyta daturae and Ascochyta sonchi are the synonyms of Boeremia exigua var.exigua.In the checklist of Polish micromycetes these species are still numbered among the Ascochyta species (Mułenko, Kozłowska 2008).
To distinguish members of the genus Ascochyta from Phoma species with secondary conidial septation, the in vitro studies are needed (Boerema et al. 2004).Thus, the revision of the genus Ascochyta based on in vitro studies and molecular analyses is necessary.Our observations indicate that some of the species included currently to the genus Ascochyta may also belong to Phoma Fr. s.l.(e.g., Ascochyta infuscans and Ascochyta sodalis), as in their pycnidia there is a contribution of unicellular conidia of variable shape and size.