Morphological Characteristics

The lichenized ascomycetous genus Protoblastenia is characterized by orange to reddish coloured, more or less domed and biatorine apothecia. The spot reaction with K (potassium) results in an intensely, or rarely weakly, purplish red reaction. This is caused by anthraquinones, giving the apothecia their conspicuous colour. The development of the thallus ranges from endolithical to distinctly epilithical and continuous to areolate or even squamulose specifications. The asci are of the Porpidia-type with a diverging tubular amyloid structure in the apical wall. The elliptical to globular ascospores are always hyaline and aseptate, the paraphyses have swollen apices, and anastomoses and ramifications are present.

Distribution

Protoblastenia species mainly occur in temperate regions of the Northern Hemisphere on calciferous stones or on soil over calciferous rock. Their habitats range from dry, sunny rock faces to more or less wet or shaded locations. Found in the Alps, with approximately seven species, the genus reaches the highest species number in Middle Europe. A few specimens of Protoblastenia are recorded from the Southern Hemisphere in South America and the Antarctic Islands. However, it has to be checked whether these collections really include members of the genus.

Phylogeny

Protoblastenia species have been frequently collected due to their rather conspicuous appearance with intensely coloured apothecia. Even so, the infrageneric relationships are still very poorly understood because of a deficiency of taxonomically useful character differences between the species. Molecular analyses of the internal spacer region (ITS) of the ribosomal DNA could result in new insights into the phylogeny of the genus Protoblastenia. Sequences of the rDNA 18S region can help understanding the taxonomic position of the family Psoraceae within the Lecanorales.

References