A Phylogenetic Study of the Genus Cookeina

Abstract

<i>Cookeina</i>, with seven recognized species, is one of the commonly encountered genera of the Sarcoscyphaceae (Pezizales) in tropical and subtropical areas around the world. Morphologically the species are distinguished by combinations of several features including ascospore shape and surface relief, presence and origin of apothecial hairs and presence or absence of gelatinous material within the cortical layer of the excipular tissue. Color of the hymenium, attributed to carotenoid pigments, is particularly variable in some collections especially those referred to as <i>C. speciosa</i>. In this study phylogenetic analyses were carried out using rDNA ITS and rDNA LSU sequences. Forty-four collections were studied which included a broad sampling of color variants of <i>C. speciosa</i> from a field site in Venezuela. The genus was shown to be monophyletic with several well-supported lineages. These analyses generally support the established, morphologically distinguished taxa within a monophyletic genus <i>Cookeina</i>. Collections referred to as <i>C. speciosa</i> segregate within a clade in which hymenial color differences are associated with groups within the clade. <i>Cookeina sinensis</i> is sister to <i>C. tricholoma</i> but is distinct from it; <i>C. indica</i> fails to resolve with any of the major clades. The placement of <i>C. insititia</i> is ambiguous but it falls within <i>Cookeina</i> and thus is considered in the genus <i>Cookeina</i> rather than in a separate genus, <i>Boedijnopeziza</i>.