Solorina
Solorina Ach., 1808
| Common name | Chocolate Chip Lichens |
|---|---|
| Field Characters | Foliose, squamulose to almost crustose tripartite or bipartite cyanolichens. Thalli varying from large rounded foliose lichens to lobes reduced to granules and cephalodia around apothecia. Upper cortex greyish-green to greyish-blue. For tripartite species, Nostoc may form a layer within the thallus, or it may form cephalodia that are hidden inside the lobe or found external to and on the lower surface of the lobe. Lower surface lacking a cortex, vaguely veined, tomentose, and with clustered simple to branched rhizines. Apothecia embedded centrally, depressed to bulging from the upper lobe surface, like round, brown melted chocolate chips. |
| Similar species & genera |
Peltigera: similar outwardly including the lack of the lower cortex, however Peltigera have apothecia that develop at the tips of lobes, not in central depressions. |
| Ecology | Terricolous, typically on calcareous soil, sometimes over moss or soil over rock. In Alberta most species are restricted to the mountains, but one can be found on mineral soil sporadically in forested regions across the province. |
| Chemistry | In Alberta, one species has an orange pigment, solorinic acid in the medulla, while no substances have been detected in other species. |
| Molecular support |
Recent phylogenetic analyses found Solorina to be polyphyletic (Zheng et al. 2025). The species with orange pigments were retained within Solorina s.s., while other sequenced species were placed within a new genus, Pseudosolorina. As with many taxonomic shifts that do not affect the species’ concepts, at this time we retain the historical genus classification. |
| Links |
Species recorded in Alberta: 5
- S. bispora Nyl. (ACIMS)
- S. crocea (L.) Ach. (ACIMS)
- S. octospora (Arnold) Arnold (ACIMS)
- S. saccata (L.) Ach. (ACIMS)
- S. spongiosa (Ach.) Anzi (ACIMS)
DICHOTOMOUS KEY – Modified from Goward 1994 and Vitikainen 2012
1a. Medulla bright orange; over acid or base-rich soil in snowy localities; alpine and subalpine…...Solorina crocea
1b. Medulla white; over base-rich soil; distribution various….. 2
2a. Thallus more or less well developed, at maturity generally more than 1.0 cm wide; upper surface never pruinose, usually continuous; apothecia weakly to sometimes deeply sunken….. 3
2b. Thallus often poorly developed, often less than 1.0 cm wide at maturity; upper surface often white-pruinose, cracked when mature; apothecia deeply sunken….. 4
3a. Upper surface predominantly pale green; thallus usually more or less rounded in outline, not lobate; spores 4 per ascus; spores 32-50 (-75) x 18-30 µm, ornamented reticulately; montane, subalpine and alpine…. Solorina saccata
3b. Upper surface predominantly brown; thallus lobate, lobes short or elongate (i.e., thallus not rounded in outline); spores 8 per ascus; spores 35-40 (-75) x 14-21 µm, ornamented with triangular structures; alpine…. Solorina octospora
4a. Thallus minute, often consisting primarily of granular cephalodia that form a supporting “cushion” around apothecia; spores 4 per ascus…..Solorina spongiosa
4b. Thallus larger, conspicuous; apothecia not associated with cephalodia; spores 2 per ascus…..Solorina bispora
RENR Students: Know Solorina crocea– be able to key this species out or recognize it (it is also covered in Brodo et al. 2001 and Goward et al. 1994).
Resources
Brodo, I. M. 2016. Keys to the lichens of North America. Revised and Expanded. Yale University Press, in collaboration with the Canadian Museum of Nature.
Brodo, I. M., S. D. Sharnoff, and S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven and London.
Goward, T., B. McCune, and D. Meidinger. 1994. The Lichens of British Columbia: Illustrated Keys. Part 1 – Foliose and Squamulose Species. Province of British Columbia Ministry of Forests Research Program, Victoria.
Vitikainen, O. 2012. Nordic Lichen Flora. Nordic Lichen Society, Göteborg.
Zheng, T., L. Wang, M. Ai, Y. Gan, R. Fan, Y. Zhang, F. R. Worthy, J. Jin, W. Meng, S. Zhang & X. Wang. 2025. Taxonomic revision of Solorina (Peltigeraceae, Ascomycota), reveals a new genus and three new species. Journal of Fungi 11: 169. https://doi.org/10.3390/jof11030169
