Adjunct Curator

Mycology / Lichenized Fungi, Department of Botany, The Field Museum

A happy lichen collector...

What are lichens?

Lichenized fungi, or lichens, are fungi with a specialized mode of nutrition: they form a species-specific symbiosis with certain kings of algae, mostly green algae (Chlorophyta and related groups) and so-called blue green algae (Cyanophyta), which in fact are related to bacteria but exhibit the same life style as eukariotic algae.

Yes, this is a lichen! It is called Chroodiscus.

My Lichen Biography In Short...

I became interested in tropical lichens when I first spent a year studying tropical biology at the University of Costa Rica. In subsequent years I specialized in lichens growing on living leaves of vascular plants, the so-called foliicolous lichens, a characteristic element of tropical rainforests. Besides clarifying their taxonomy and systematics, emphasis was laid on their world and regional distribution patterns, as well as their ecology, including habitat and microhabitat preferences, such as altitudinal zonation and phorophyte relations. I also established a set of environmental index values at the species level, which can be used to estimate parameters such as relative light intensity based on the foliicolous lichens present at a microsite or on a leaf, or the degree of disturbance of a particular area of rainforest. Furthermore, foliicolous lichens are used as model organisms to study the mechanisms that maintain high diversity of ecologically equivalent, coexisting species. Other studies relate to the interactions between foliicolous lichens and other organisms in the phyllosphere, in particular lichen-feeding invertebrates and lichenicolous fungi.

Current Research Projects

I have now extended my research interest towards corticolous microlichens in the tropics, a group of lichens that is highly diverse in tropical rainforest canopies but whose taxonomic knowledge is quite rudimentary, and whose importance for tropical rainforest ecosystems is virtually unknown. Research projects that are presently under way include (1) phylogenetic studies of the lichen families Asterothyriaceae, Gomphillaceae, and Ectolechiaceae, including phenotype and genotype data, (2) a monograph on foliicolous lichens for the series Flora Neotropica (ca. 500 species), (3) an assessment of lichen biodiversity in Costa Rica (coordinated by Dr Harrie Sipman, Germany), (4) an approach to the foliicolous and corticolous microlichen flora of Mexico (joint project with Dr Maria de los Angeles Herrera Campos, UNAM), (5) a preliminary compilation of neotropical corticolous microlichen diversity, and (6) an illustrated lichen flora of the State of Illinois (collaboration with Gerould Wilhelm). Information on these and other research projects, as well as many nice lichen pictures, are available online from THE FOLIICOLOUS LICHEN HOMEPAGE