Verrucariaceae Thelidium decipiens Growth type crustose Chemical results negative Frequent on calcareous rocks, limestone and mortar. Immersed creamy-white or brownish thallus with scattered perithecia sunken in pits and usually surrounded by a narrow crack. The ostiole is inconspicuous. Spores 0-1 septate, (19-)25-33(-41) × (9-)11-14(-19) µm. Microscope photographs below. Similar: Thelidium papulare and T. incavatum. Spores 3(-5)-septate

Microscope photographs



Thelidium decipiens
Shapwick and Puddletown, Dorset. March 2014, May 2017