Saturday, August 28, 2010

Virginia Lichen Checklist

Back in 2004 I began assembling the first checklist of Virginia lichen taxa. The first draft of this work consisted of a literature review plus an inventory of Virginia specimens held by the DUKE Cryptogamic Herbarium (DUKE) and various herbaria with publicly-accessible databases. However, I decided not to publish any of that work, instead favoring an approach that would produce a list of expert-verified taxa for the state. I did this because I was in a unique position to correct some of the taxonomic problems that have arisen over the years, and a literature review with an herbarium inventory would only perpetuate previous errors.

Beginning in 2006, I worked primarily with Dr. Richard C. Harris ('Dick') of the New York Botanical Garden to assemble the lichen checklist for the state, and ensured that Dick verified at least one specimen for each taxon in the list. This resulted in the first checklist of Virginia lichens, lichenicolous fungi, and allied taxa, published last year in Evansia (Hodkinson et al. 2009). However, taxonomy is ever-evolving, and new species are constantly being discovered. To address this issue, I have designed a website that can be updated at any time to reflect changes in our understanding of the Virginia lichen flora:
Virginia’s physiographic provinces

The most recent addition to the list, from just this week, is the lichenicolous fungus Skyttea radiatilis (Tuck.) R.Sant., Etayo & Diederich, identified by James Lendemer. The species was described just within the past decade; it seemingly grows only on a single sterile crustose lichen species, and is probably not rare, even though it is seldom collected and identified. In order to understand why it is so seldom seen, one must simply ask: 'How many people are collecting and carefully examining sick-looking sterile crustose lichens?' (Hint: not many). Additions like this have brought the total number of verified taxa for the state to just over 600, and additional collecting work that I have recently done in the outer Coastal Plain of Virginia has revealed many more (keep an eye out for this work, to be published sometime next year).

I welcome any comments or corrections to the Virginia Lichen Checklist. Let us not forget that, since so much remains to be discovered about the diversity of lichenized fungi, regional inventories like this one are still crucial for the advancement of the field!



Hodkinson, B. P., R. C. Harris, and M. A. Case. 2009. A Checklist of Virginia Lichens. Evansia 26(2): 64-88.
Download publication (PDF file)

Hodkinson, B. P., R. C. Harris, and M. A. Case. 2010. A Checklist of Virginia Lichens. [updated: 25 August 2010].
View authors' updated checklist (website)

Hodkinson, B. P., and M. A. Case. 2008. A lichen survey of Williamsburg, Virginia. Banisteria 31: 24-30.
Download publication (PDF file)
Download supplement (Excel file)

Hodkinson, B. P. 2010. A First Assessment of Lichen Diversity for One of North America's 'Biodiversity Hotspots' in the Southern Appalachians of Virginia. Castanea 75(1): 126-133.
Download publication (PDF file)

Monday, August 16, 2010

Parmelia barrenoae

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!


Works Cited:

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.

Hodkinson, B. P., J. C. Lendemer, and T. L. Esslinger. 2010. Parmelia barrenoae, a macrolichen new to North America and Africa. North American Fungi 5(3): 1-5.
Download publication (PDF file)
View journal volume (website) 
View sequence data (NCBI website)

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.
Download publication (PDF file)