[Latest update: October 31st, 2000]

Tricharia albostrigosa	Arthonia cyanea	Mazosia rotula
Chroodiscus coccineus	Trichothelium argenteum	Opegrapha viridistellata
Coccocarpia stellata	Badimia elixii	Echinoplaca atrofusca

These selected foliicolous lichen species demonstrate the great variety of forms and colours.
(Photographs by Robert Lücking)

[Numbers in brackets relate to relevant publications; underlined phrases without links indicate pages under construction].

 

Foliicolous lichens inhabit the surface of living leaves of vascular plants [SANTESSON, Symb. Bot. Ups. 12(1): 1-590 (1952)]. They are found in tropical rain forests but extent into subtropical or temperate zones whenever conditions are appropriate. Three categories can be distinguished: (1) Typically foliicolous lichens, predominantly found on leaves where they complete their entire life cycle; (2) ubiquitous lichens, abundant on leaves but also on other substrata; (3) facultatively foliicolous lichens, mainly growing on other substrata and only occasionally found on leaves, then usually with small thalli and without or with immature reproductive structures [64]. Typically foliicolous lichens are of particular interest, since they show special adaptations, often in convergence with foliicolous bryophytes [17]. Like saxicolous (rock-inhabiting) or corticolous (bark-inhabiting) taxa, the foliicolous lichens are an ecologically defined group and do not form a systematic entity. Typically foliicolous lichens are found throughout all lichenized Asco- and Basidiomycetes but are without exception crustose; the few foliose representatives commonly found on leaves are ubiquitous lichens.

The world monograph of SANTESSON [loc. cit.] is the primary reference for foliicolous lichen research. Before that, more than 800 taxa had been described by workers like Fée, Fries, Montagne, Nylander, Krempelhuber, Müller Argoviensis, Vainio, Zahlbruckner, Schilling, and Malme. Santesson accepted 235 taxa and reduced the remainder to synonymy. Due to the work of subsequent researchers, this number has meanwhile more than doubled [FARKAS & SIPMAN, Abstr. Bot. 21: 173-206 (1997)]. Supported by the German Academic Exchange Service (DAAD), the German Research Society (DFG) and the European Science Foundation (ESF), since 1987 our research projects contribute to the knowledge on foliicolous lichens in various fields:

• Taxonomy, including description of new species and genera [1, 7-8, 10-13, 18, 23-27, 29, 32, 34, 36, 38, 40-41, 43, 45, 47-50, 59-60, 62, 64-66, 68-72].

• Floristics, with emphasis in Central and South America [2, 5, 7-8, 12, 18, 20, 23-27, 31, 36, 40-41, 46, 50, 61, 63-66, 70-71, 73, 77, 80].

• Biogeography, comparing neotropical and paleotropical rainforest areas [27, 28, 42, 61, 73, 77, 80].

Ongoing international projects include cooperation with colleagues and institutions in various parts of the world, in particular from the United States, Guatemala, Costa Rica, Colombia, Venezuela, Ecuador, Peru, French Guiana, Brazil, Uruguay, Argentina, Spain, Great Britain, Sweden, The Netherlands, Belgium, Switzerland, Austria, Poland, Czech Republic, Japan, and Australia.

A first checklist summarizing the state-of-the-art in foliicolous lichen research was published by FARKAS & SIPMAN [Trop. Bryol. 7: 93-148 (1993)]. This checklist was updated four years later [FARKAS & SIPMAN, Abstr. Bot. 21: 173-206 (1997)]. When constructing this web-page, it was decided to design a modified checklist to be placed on the Internet for regular update. This Checklist of foliicolous lichens and their lichenicolous fungi is published in co-operation with E. Farkas (Vácrátót, Hungary), E. Sérusiaux (Liège, Belgium) and H. J. M. Sipman (Berlin). It follows a slightly different layout than the previous checklists, including all basionyms of foliicolous lichens ever described, as well as all synonyms used after SANTESSON [loc. cit.] and all currently accepted names of genera and species.

Besides foliicolous lichens, also checklist of lichenicolous fungi growing on them is also provided, in cooperation with P. Diederich (Luxemburg) and J. Etayo (Pamplona, Spain). Lichenicolous fungi use the phycobiont of the lichen on which they grow to obtain photosynthetic products. Because some genera, such as Arthonia or Opegrapha, also include lichenized species, research on lichenicolous fungi is traditionally connected to the study of their host lichens. Presently about 70 species of lichenicolous fungi on foliicolous lichens are known. The primary reference is the monograph of MATZER [Mycol. Papers 171: i-x, 1-202 (1996)].

The lichenicolous fungi Arthonia cryptotheciae (on Cryptothecia candida) and Opegrapha velata (on Gyalectidium filicinum):
Two examples of genera in which both foliicolous lichens and lichenicolous fungi are known.
(Photographs by Robert Lücking)

The checklist will in the future be accompanied by a world-based Key to genera and species of foliicolous lichens and their lichenicolous fungi, including typically foliicolous and ubiquitous taxa. Parallel to this, a Floristic checklist of foliicolous lichens and their lichenicolous fungi will be prepared, giving detailed information on the distribution of all taxa, as well as species lists for all countries. Regular notes and an updated list also will be published on Lichenes Foliicoli Exsiccati, an exsiccate dealing entirely with foliicolous lichens [7-8, 23-26, 43]. Following FARKAS & SIPMAN [loc. cit.], a complete Bibliography on foliicolous lichens and their lichenicolous fungi, i.e. a list of all literature references dealing with foliicolous lichens and their lichenicolous fungi, will also be presented.

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