• Polyblastia albida Arnold
Polyblastia albida
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(Map updated: 11 August 2009)

Like some members of Verrucaria, for example, V. baldensis, this species forms ‘burrows’ or pits in limestone. The lichen hunter is compelled to dig them out with the edge of a razor blade and squash the contents between a cover slip placed on a microscope slide. The thallus is barely visible as a stain. The spherical discs (perithecia) immersed in the rock have their tops freed from the side of the pit by a narrow crack (hand lens). The disc is not reinforced above by a thick outer layer (involucrellum). The spores are muriform and colourless 25-50 x 12-25ųm, 8/ascus). On hard, well-lit limestone, or damp walls. Northern and western Ireland.

Key characteristics

  • Dots the surface of hard limestone with pits so must be dug out
  • Spores muriform, with 10-36 cells present.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Polyblastia albida Arnold. [In] LichenIreland. Accessed on 2020-01-21.