Botanische Staatssammlung München, Menzinger Strasse 67, D-80638 München, Germany.
Stud Mycol. 2007;58:95-104. doi: 10.3114/sim.2007.58.04.
Cladosporium chlorocephalum (= C. paeoniae) is a common, widespread leaf-spotting hyphomycete of peony (Paeonia spp.), characterised by having dimorphic conidiophores. During the season, one stage of this fungus causes distinct, necrotic leaf-blotch symptoms on living leaves of Paeonia spp. In late autumn, winter or after overwintering, a second morphologically distinct conidiophore type occurs on dead, blackish, rotting stems. Conspecificity of the two morphs, previously proposed on the basis of observations in culture, was supported by DNA sequence data from the ITS and LSU gene regions, using cultures obtained from leaf-blotch symptoms on living leaves, as well as from dead stems of Paeonia spp. Sequence data were identical, indicating a single species with two morphs. On account of its distinct conidiogenous loci and conidial hila, as well as its sequence-based phylogenetic position separate from the Davidiella/Cladosporium clade, the peony fungus has to be excluded from Cladosporium s. str., but still belongs to the Davidiellaceae (Capnodiales). The leaf-blotching (cladosporioid) morph of this fungus morphologically resembles species of Fusicladium, but differs in having dimorphic fruiting, and is phylogenetically distant from the Venturiaceae. The macronematous (periconioid) morph resembles Metulocladosporiella (Chaetothyriales), but lacks rhizoid conidiophore hyphae, and has 0-5-septate conidia. Hence, C. chlorocephalum is assigned to the new genus Dichocladosporium.
头状壳二孢 (= 壳球孢属石楠叶点霉)是一种常见的、广泛分布的牡丹叶斑生丝孢真菌，其特征是具有二态分生孢子梗。在季节期间，这种真菌的一个阶段会在牡丹属植物的活叶上引起明显的坏死性叶斑症状。在深秋、冬季或越冬后，在死的、黑色、腐烂的茎上会出现第二个形态上明显不同的分生孢子梗类型。两种形态的同物异性，以前基于在培养物中的观察提出，得到了来自 ITS 和 LSU 基因区域的 DNA 序列数据的支持，使用来自活叶上的叶斑症状以及牡丹属植物的死茎获得的培养物。序列数据相同，表明这是一个具有两种形态的单一物种。由于其独特的分生孢子发生部位和分生孢子梗，以及其基于序列的系统发育位置与 Davidiella/Cladosporium 分支分开，牡丹真菌必须从 Cladosporium s. str. 中排除，但仍属于 Davidiellaceae (Capnodiales)。该真菌的叶斑（壳球孢属）形态在形态上类似于 Fusicladium 属的物种，但在二态生殖方面有所不同，并且在系统发育上与 Venturiaceae 相距甚远。长形的（围管孢型）形态类似于 Metulocladosporiella (Chaetothyriales)，但缺乏根状分生孢子梗菌丝，并且具有 0-5 个分隔的分生孢子。因此，头状壳二孢被分配到新属 Dichocladosporium。
