Recently I published an article in the journal North American Fungi on the distribution and morphology of the foliose lichen Parmelia barrenoae (Hodkinson et al. 2010). One significant aspect of this paper is that it highlights the importance of good herbarium collections. Bill and Chicita Culberson traveled to Morocco in 1971, and to Calfornia in 1972; on both trips, they collected generally, and happened to pick up specimens of P. barrenoae without knowing it (since the species was not yet described). However, when I went into the DUKE herbarium to look for specimens, I found two continental records (for both Africa and North America) just sitting there!
The species was described from Spain a few years back (Divakar et al. 2005), but the emphasis of the originial paper was on the molecular phylogeny and the fact that this distinctive species was differentiated by having simple rhizines (as opposed to the squarrose rhizines seen in the closely-related Parmelia sulcata). An examination of the herbarium material from a broader geographic range allowed us to additionally highlight the fact that the species has distinct soralia that are erose, instead of the more erumpent soralia seen in Parmelia sulcata.
Figure 1. Parmelia barrenoae (A-E; all from Lendemer 19720) and comparison of rhizines with P. sulcata (F, from McGarrity s.n.). A, lobe morphology (scale = 2.0 mm). B, detail of lobe tip (scale = 0.5 mm). C, young soralium (scale = 0.5 mm). D, soralia (scale = 1.0 mm). E-F, comparison of rhizines in P. barrenoae (E) and P. sulcata (F) (scale = 0.2 and 0.5 mm respectively).
Several lichenologists (e.g., Trevor Goward and Ernie Brodo) had recognized this entity in western North America as a species not on the continental checklist (N.A. lichen checklist), but Ted Esslinger recognized it as P. barrenoae and James Lendemer generated the ITS rDNA sequence data confirming it. Additional ITS rDNA sequences from this species recently deposited in GenBank from Morocco and Turkey (previously deposited sequences were from Spain, and ours from California) give molecular barcode sequence data from throughout the species's known worldwide range. Now there is at least one ITS sequence (the more-or-less 'official' fungal barcode) from each of the continents from which the species has been reported, giving a good sampling of the sequence diversity found across its range.
For another nice set of photos of this species, check out these ones on MushroomObserver.com!
Divakar, P. K., M. C. Molina, H. T. Lumbsch, and A. Crespo. 2005. Parmelia barrenoae, a new lichen species related to Parmelia sulcata (Parmeliaceae) based on molecular and morphological data. Lichenologist 37: 37-46.
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After posting this, I was alerted to the following article in Spanish, which gives some additional discussion of morphology and ecology, with some nice micrographs:
Barreno, E., and M. A. Herrera-Campos. 2009. Parmelia barrenoae Divakar, MC. Molina & A. Crespo un liquen nuevo para la flora asturiana. Bol. Cien. Nat. R.I.D.E.A. 50: 333-341.
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