• Thelotrema isidioides (Borrer) R.Sant.
Thelotrema isidioides
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(Map updated: 11 August 2009)

Known only from County Cork and extraordinarily rare being a true native of the juniper forests of the Azores, this lichen forms small patches of grey-brown or yellowish crust on rock, the K+ orange, Pd+ orange thallus forming a series of ridges and depressions like a beaded pattern hammered into an antique snuffbox by a silversmith. The spherical discs (0.20.3mm diam.) are partially sunken with only the black tips (ostiole) visible. The brown, muriform spores are usually eight/ascus with 11 or less transverse septa.

Key characteristics

  • Thallus a brown to yellowish, low, sharply beaded crust with the discs almost sunken into the blistered areoles, K+ orange, Pd+ orange
  • Spores muriform, in eights, usually 79 transverse septa.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Thelotrema isidioides (Borrer) R.Sant.. [In] LichenIreland. Accessed on 2020-05-26.