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Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta (Taylor) Ertz & Tehler

Synonyms:

Sclerophytonomyces circumscriptus Sparrius & P. James

Peterjamesia circumscripta (Taylor) D. Hawksw.



Family: ROCCELLACEAE

Habitat: Xeric supralittoral  zone

Description

   Thallus more or less circular, 1 to 5 cm in diameter, very often forming mosaics, moderately thick, 0.2-0.25 mm, finely powdery with calcium oxalate crystals, rimose to crackle and forming areoles of 1 -2 mm with jagged edges, pale grayish if very fertile, otherwise white-greyish, dirty white a little yellowish, gray-yellowish but becoming orange or orange-yellow if altered or scraped by the presence of the photobiont which is a Trentepohlia, prothallus most often very clear with slightly lacerated, blackish edges. Apothecia up to 0.1 mm in diameter, buried in the thallus and appearing as small black dots, flat, black disc, powdered with whitish. Spores very elongated, brownish when mature, (4) 5 (7) septate, 17-25 x 5-6 µm. C-, K-, KC+ pale yellowish, P+ yellow-orange. Common species of rocky coasts coming under the overhangs of dry siliceous rocks sheltered from rain and direct light.

N.B. Very variable species depending on exposure to light (there are probably several taxa) with an Enterographa appearance sometimes associated with Ingaderia sorediata, (formerly considered as a variety!) but the two species do not have the same colours together: Roccellographa (Peterjamesia) circumscripta has a general greyish-whitish-yellowish colours and Ingaderia sorediata has a general pale grayish colours, slightly bluish in its soredia.
 
We can distinguish :
 
Roccellographa circumscripta forme de l'ombre. The “classic” form occurring in poorly lit and humid places with “chain” apothecia.
 
Roccellographa circumscripta Cf. forme exposée au soleil. With a thick, yellowish-gray thallus with lorel-like apothecia that grows on well-lit dry rocks (perhaps a different taxon?).
 
_ Can form mosaics with itself or with Ingaderia sorediata.
 
_ Sometimes associated with Sparria endlicheri, in less sunny places but Cliostomum tenerum, Ingaderia vandenboomii (Llimonaea sorediata), Dirina massiliensis f. sorediata can also come nearby in slightly brighter places.
 
Reichlingia dendritica (Arthonia atlantica) is a fairly similar species which in the field is K+ yellow and P+ pale yellow or pale red and not yellow-orange and which does not leave an orange stain when scratched.




Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta & Ingaderia sorediata Ponte du Van 2
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta & Ingaderia sorediata Pointe du Van 1
Alain GERAULT

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe du Van 3
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta & Ingaderia sorediata Pointe de Pen-Hir 1
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe de Pen-Hir 2
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe de Pen Hir 3
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe de Pen Hir 4
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe de Primel 1
Bernard BOUFFINIER

Roccellographa circumscripta (Taylor) Ertz & Tehler

Roccellographa circumscripta Pointe de Primel 2
Bernard BOUFFINIER



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