• Collema subnigrescens Degel.
Collema subnigrescens
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This conspicuous lichen of nutrient-enriched trees differs from C. nigrescens in its isidia-free thallus and broader spores (6-6.5ųm compared to 3-4.5ųm). C. furfuraceum is also similar, but has isidia. It is known from Counties Kerry, Galway and Clare, and more recently from the north-west. It is rare on blackthorn, hazel and oak. There is some debate as to whether some historical records of this species refer instead to the rarer C. nigrescens.

Key characteristics

  • Thallus without isidia; discs common; spores broader than in C. nigrescens
  • On nutrient-rich bark and rock, mostly in the oceanic woodlands of the west.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Collema subnigrescens Degel.. [In] LichenIreland. Accessed on 2018-08-16.