Notes: A single isolate from house dust collected in New Zealand [DTO 305-E8] morphologically fits the concept of the recently described species C. austrohemisphaericum which was isolated from black mould on the surface of a fruit in New Zealand. Therefore, it is herein treated as an additional isolate of that species although all four known isolates sit on quite long branches in a well-supported clade (Fig. 3, clade 9) and may each represent a cryptic species. For now we refrain from introducing further novel species for these morphologically similar isolates until additional isolates are available to formalise species concepts for these lineages.

This species is undoubtedly a widespread saprobic hyphomycete commonly isolated from indoor environments. Morphologically it is comparable with C. cladosporioides (Fig. 1, clade 66) but C. delicatulum (Fig. 1, clade 44) differs from the latter species in having 0−1-septate intercalary conidia and secondary ramoconidia, only a few conidia in the terminal unbranched part of conidial chains, shorter often slightly geniculate conidiophores and shorter secondary ramoconidia. Cladosporium westerdijkiae (Fig. 1, clade 43) is the closest relative in the tree but can be distinguished from C. delicatulum by usually aseptate and somewhat longer ramoconidia and secondary ramoconidia.

Notes: Bensch et al. (2010, 2012) already discussed the phylogenetic variability within the subclades of C. perangustum (Fig. 1, clade 4, previously also including clades 2 and 3) but based on the quite conserved morphology refrained from splitting this species based on the sampling available at that stage. However, Sandoval-Denis et al. (2016) introduced two additional species, C. angulosum (Fig. 1, clade 2) and C. xanthochromaticum (Fig. 1, clade 3) for two of the subclades of C. perangustum.

Notes: Cladosporium pseudocladosporioides (Fig. 1, clade 56) is a common, widespread saprobic hyphomycete phylogenetically and morphologically very close to C. cladosporioides (Fig. 1, clade 66) but clearly distinct by forming a separate lineage in phylogenetic analyses (also see Bensch et al. 2010) and by having shorter and somewhat narrower, 0−1(−2)-septate secondary ramoconidia, narrower conidiogenous loci and hila, and hyphae sometimes forming ropes. However, the distinction between the two species only based on morphology is difficult and not always possible with certainty, which is additionally complicated by the internal genetic structure of the C. pseudocladosporioides clade, suggesting that it possibly represents a complex containing cryptic species (observed in both the act and tef1 alignments in Bensch et al. 2010). Uncertain strains should simply be referred to as C. cladosporioides s. lat. (complex). Cladosporium paracladosporioides (Fig. 1, lineage 13) is also similar but differs in having wider 0−3-septate secondary ramoconidia, wider conidiogenous loci and hila and is phylogenetically distinct (see Bensch et al. 2010).

Notes: Cladosporium uwebraunianum (Fig. 1, clade 52) is closely related to C. australiense (Fig. 1, clade 51), but morphologically they are clearly differentiated. The former species is characterised by shorter conidiophores (up to 95(–135) µm), longer conidiogenous cells (17–50(–65) µm) and conidia formed in long branched chains with up to 10(–13) conidia in the terminal unbranched part of the chain. In contrast, C. australiense exhibits very long, seta-like conidiophores (48–285 µm long) with shorter conidiogenous cells (6–15(–40) µm) and conidial chains with only 2–4(–5) conidia in the terminal part of the chain (Bensch et al. 2010). Cladosporium funiculosum (Fig. 1, clade 55) is morphologically very similar in also forming quite long conidial chains with 8(–14) conidia in the unbranched terminal part, but the chains are often dichotomously branched and the conidiophores narrower (2–3 µm).

Notes: This new species (Fig. 1, clade 34) is formerly known as C. cladosporioides Lineage 2 sensu Bensch et al. (2010). Bensch et al. (2010) hesitated in naming this phylogenetically distinct lineage since it is morphologically almost indistinguishable from C. cladosporioides s. str. Morphologically, C. vicinum is the closest of the three phylogenetically distinct lineages to C. cladosporioides s. str. (Fig. 1, clade 66) but differs in more frequently forming septate conidia (usually aseptate in C. cladosporioides s. str. vs 0–1(–3)-septate in C. vicinum). Cladosporium europaeum (formerly C. cladosporioides Lineage 1 sensu Bensch et al. (2010); Fig. 1, clade 35) is the closest phylogenetic relative of C. vicinum (see species notes under C. europaeum for sequence similarities) but produces somewhat shorter conidiogenous cells, secondary conidia and ramoconidia. Cladosporium westerdijkiae (formerly C. cladosporioides Lineage 4 sensu Bensch et al. (2010); Fig. 1, clade 43) introduced below differs from C. vicinum in having shorter intercalary conidia and secondary ramoconidia which are usually aseptate.