| TAXON: | Cladonia rangiformis Hoffm. (1796) |
| RECENT SYNONYMS: | – |
| FAMILY: | Cladoniaceae |
| GROWTH FORM: | Secondary thallus fruticose, heteromerous (podetiate); primary thallus crustose, heteromerous (squamulose) |
| SUBSTRATES: | Mineral soil |
| PHOTOBIONT: | Asterochloris alga |
| REPRODUCTION: | Pycnidia; apothecia rare |
| ASCUS: | If present, elongate-clavate; apex thickened, with K/I+ blue tholus and deep-blue gelatinous outer sheath; 8 spores |
| SPORES: | Conidia curved; ascospores if present ellipsoid |
| NOTABLE FEATURES: | Podetia corticate, hollow, dichotomously and openly branching; cortex mottled green and white, sometimes brown; apothecia if present brown, in corymbose clusters; primary thallus evanescent |
| CHEMICAL TESTS: | Thallus K+ yellow, Pd+ pale yellow or occasionally red, K/UV(dry)+ yellow (atranorin, rangiformic acid, ±fumarprotocetraric acid) |
| HABITAT: | Grassland, dunes, among coastal rocks and cliffs |
| DISTRIBUTION: | Widespread and common in Britain, especially along coast and in lowlands |
| CONSERVATION STATUS: | Least Concern |
| LICHENICOLOUS FUNGI: | Bachmanniomyces punctum, Didymocyrtis cladoniicola, Heterocephalacria bachmannii, Niesslia cladoniicola |
| IDENTIFICATION DIFFICULTY: | Green 1: Field identification possible |
| CONFUSION SPECIES: | Cladonia furcata |
FIELD NOTES
Cladonia rangiformis is one of the three most common ‘reindeer lichens’ in Britain, alongside C. furcata and C. portentosa. You’ll find it in grasslands, dunes and soil pockets on rock, where it tends to grow in tangly, thicket-like tufts. It typically appears distinctly mottled, with areoles of green algae contrasting with pale medulla in a pattern like ‘giraffe spots’ or ‘crazy paving’.
C. rangiformis is fairly easy to distinguish from its common cousins. C. portentosa lacks a cortex, branches trichotomously rather than dichotomously, and tends to look more uniformly paler. And though C. furcata is corticate and dichotomously branching, it branches more sparsely and narrowly, lending it a taller and more gracile look.
That said, it’s possible to confuse C. rangiformis and C. furcata. It’s often thought that C. rangiformis looks more mottled green and white, while C. furcata looks browner. But while this distinction holds in general, C. rangiformis can also take on a brownish tinge in sunnier situations, and C. furcata a mottled pattern in shadier ones.
If you’re unsure, spot-tests can help. C. rangiformis always reacts K+ yellow from atranorin, and only occasionally Pd+ red from fumarprotocetraric acid. By contrast, C. furcata only occasionally reacts K+ yellow, and always Pd+ red.
If you find your K-test hard to interpret, the K/UV(dry)+ yellow test for atranorin is more sensitive. Images of both tests are shown below. Note also that atranorin often gives a Pd+ pale-yellow signal, which isn’t usually mentioned in British flora.
Ultimately, though, spot-tests can’t always separate C. rangiformis and C. furcata, especially the very similar C. furcata subsp. subrangiformis. But they can help to confirm an identification you’ve reached on the basis of external appearance. The difference in branching — more richly and widely for C. rangiformis, and more sparsely and narrowly for typical morphs of C. furcata — is perhaps the most helpful characteristic.
LAB NOTES
Cladonia rangiformis can normally be identified without microscopy.
SPECIMENS
Cladonia rangiformis : England : VC25 East Suffolk : TM4077 : September 2024 : On mineral soil
Cladonia rangiformis : Scotland : VC101 Kintyre : NR6974 : August 2024 : On mineral soil
Cladonia rangiformis : England : VC14 East Sussex : TQ9418 : July 2024 : On mineral soil
Cladonia rangiformis : England : VC25 East Suffolk : TM4770 : May 2024 : On mineral soil
Cladonia rangiformis : England : VC25 East Suffolk : TM4770 : May 2024 : On mineral soil
