Caloplaca herbidella

Caloplaca herbidella

Caloplaca herbidella

Description & Identification

Distinguished by abundant white-grey rod-like coralloid isidia (rarely sparse and granular) which cover and obscure much of the thin, elephant grey-coloured thallus. Apothecia are often not present, but when they are they can be abundant and of a wonderful bright rust to perargonium-red colour. They are 1-3 mm diam., rounded to flexuose and the margin is often barely visible and of a similar colour to the disc.  Chemical tests: Thallus and isidia K- (isidia tips sometimes K+ faint purple and thalli with a yellow tige may react); apothecia K+ purple.

Thallus with isidia but no apothecia. (Photo: K. van Herk)

Thallus with abundant apothecia. (Photo: Ray Woods)

Similar Species

Recently C. coralliza has been found to be British (Arup & Akelius 2009) with a single record from Levens Park, Cumbria. It occurs also on trees, is very rarely fertile and then with only a few apothecia. Most specimens have a distinct light beige to dark or orange-brown coloured thallus and isidia. The isidia tend to be formed more in discrete coral-like clusters though they may coalesce.  When this happens the crust of isidia frequently cracks into seperate islands or areoles. In C. herbidella such dense turves of isidia are rare and never crack. C. herbidella may also superficially resemble Caloplaca ferruginea, though the latter lacks isidia . Thalli without apothecia can resemble forms of some Porina species though they all tend to occur in shaded or sheltered situations and C. herbidella is a lichen of well-lit pasture woodland trees. Caloplaca chlorina has a darker grey thallus with a blue tinge, and occurs on rock rather than trees. Pertusaria coronata is K+ yellow, Pd+ orange.

Records from Wales
Location Grid Reference Last Rec'd Recorder SSSI

Brecknock: S. of Comin-Coch



R.G. Woods


Brecknock: Nr. Pencaer-helm SN98695415 2011 R.G. Woods No
Brecknock: Garth House SN941499 1997 R.G. Woods No
Brecknock: Llanwrthwl - Field near Caegarw. SN978624 2011 R.G. Woods No
Brecknock: Llanwrthwl - near Crynfryn SN978626 2009 R.G. Woods No
Carmarthen: Glan Bran Deer Park SN799378 1995 R.G. Woods No
Montgomery: Gregynog Great Wood SO079976 1990 R.G. Woods Yes
Radnor: Stanage Park  SO3371 2007 Welsh Lichen Group No
Radnor: nr. Newbridge-on-Wye SO020559 2009 S.P.Chambers No
Radnor, Tyn Coed, Disserth SO02895541 2010 RG Woods No


NBN Taxon Key