Eudarluca Speg., Revta Mus. La Plata 15: 22 (1908)

Hyperparasitic associated with rust species (but not necessarily parasitic) on various hosts. Sexual state: Ascomata scattered, solitary to gregarious, immersed to semi-immersed under pseudoclypeus, uni to multi-loculate, subglobose to irregular in shape, glabrous, dark brown to black, ostiole central, with minute papilla. Peridium thin-walled, composed of brown to dark brown, flattened, pseudoparenchymatous cells, arranged in a textura angularis. Hamathecium composed of numerous, filamentous, distinctly septate, frequently anastomosing, broadly cellular
pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate, cylindrical, short pedicellate, apically rounded, with well-developed ocular chamber. Ascospores phragmosporous, overlapping 2-seriate, fusiform or oblong with rounded ends, pale brown, septate, smooth-walled. Asexual state: see notes.
Type species: Eudarluca australis
Phylogenetic study: None

Notes: Eudarluca was introduced by Spegazzini (1908) and typified by Eu. australis which is associated with a rust on leaves of Canna. Eriksson (1966) treated Eu. australis as a synonym of Eudarluca caricis (Fr.) O.E. Erikss. Eudarluca caricis has been reported from various hosts, mostly in its presumed asexual state, Sphaerellopsis (Yuan et al. 1998; Nischwitz et al. 2005; Zhang et al. 2012). The asexual and sexual state connection between Eudarluca caricis and Sphaerellopsis filum was derived from ascospores growing on Puccinia extensicola-oenotherae (Mont.) Arthur on Carex sp. in Pennsylvania, USA (Keener 1951) and confirmed by Yuan et al. (1998). Yuan et al. (1998) grew ascospores of Eudarluca caricis on PDA and derived Sphaerellopsis conidia and conidiomata after 12 days. Zhang et al. (2012) compared the ITS sequence of Eudarluca caricis strain MullMK in GenBank with Leptosphaeria species and mentioned that Eudarluca should be treated in Leptosphaeriaceae due to comparable sequences and also morphological characters. However, both the generic type of Eudarluca and Sphaerellopsis have never
been linked (Wijayawardene et al. 2014b).

 Molecular studies on Eudarluca are limited to species variation and are based on Sphaerellopsis strains (Nischwitz et al. 2005; Bayon et al. 2006; Zhang et al. 2012). The ITS gene phylogenetic analysis showed that Eudarluca ciricis (strains MosID6 and MullMK) cluster in Leptosphaeriaceae. However, the generic type of Sphaerellopsis has found on Quercus, while the type of Eudarluca is from Canna. These two generic types have not been linked by molecular data.We suggest that caution should be followed when treating these taxa, as Eu. australis is immersed in the Canna leaves and although associated with the rust fungi (Sphaerellopsis) on Canna, it does not seem to grow on the rust.

In this study, we tentatively place Eudarluca in Phaeosphaeriaceae based on its morphological characters which
are typical of Phaeosphaeria as the peridium is thin-walled, and composed of pseudoparenchymatous cells, asci are cylindrical, subsessile to short pedicellate and ascospores are fusiform and phragmosporous. Fresh collections of Eu. australis are needed for epitypification and molecular study. Sphaerellopsis may belong in Leptosphaeriaceae where it is tentatively assigned.