PART 1
PART 1
PART 1
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Afro-montagnard Centre-oriental: env. du km 42 de la route Bukavu-Walikale, alt. env. 2300 m,<br />
épiphylle sur Connarus longestipitatus, Lambinon 71/1178 (LG, holotype, not seen).<br />
Thelenella sp. Buck 18291A<br />
Although known only from a small collection from Puerto Rico, this species is included as it extends the<br />
limits of Thelenella. The ascospores are transversely 3-septate and the thallus is scanty but in other respects<br />
it seems to be a typical Thelenella. The ascospores although small overlap the lower end of the ranges of<br />
several muriform-spored species.<br />
PUERTO RICO. Distr. Ponce: Caribbean National Forest, Toro Negro Division, along Hwy. 143 at Km 20.5,<br />
ca. 100 m, on roadside pebble, 4 Nov 1990, Buck 18291A (NY).<br />
TRICHOTHELIALES<br />
TRICHOTHELIACEAE (Müll. Arg.) Bitter & Schilling<br />
Since my brush with this family in my student days I have tended to avoid it being aware of the problems<br />
involved with defining species. Recently it has received considerable attention. A family treatment for the<br />
Guianas (Aptroot & Sipman, Flora of the Guianas, Series E, fasc. 2, 1993), saxicolous Southern Hemisphere<br />
taxa (McCarthy, Biblioth. Lichenol. 52, 1992), Clathroporina (McCarthy, Lichenologist 27: 321-350. 1995) and<br />
a revision of the genera (Hafellner & Kalb, Biblioth. Lichenol. 57: 161-186. 1995).<br />
The first, the treatment for the Guianas, is rather unfortunate. For historical reasons and differing<br />
approaches by the two authors, this is the kind of publication that gives a bad name to mycological αtaxonomists<br />
struggling to deal with biodiversity before it is gone. It leaves us open to criticism (and denial of<br />
funding) by those employing more sophisticated techniques. Three "species" concepts for ascospore variation<br />
are used in the work without adequate warning or explanation. Following Santesson (1952) Sipman divided<br />
foliicolous Porina into very narrowly defined species. In contrast Aptroot used a very broad concept for the<br />
corticolous species, with what I would consider an unacceptably large amount of variation. A third treatment of<br />
ascospore variation is found in Trichothelium where a distinct morphotype is assigned to the varietal level. I<br />
think that as α-taxonomists we have an obligation to be consistent in our species concepts within a group or, if<br />
not, then to provide some "hard" evidence as to why not. The treatment is also flawed in more obvious ways,<br />
types of taxa described from the Guianas have not been studied and names have been used with little logic<br />
(see criticisms by McCarthy, 1995). Such an interesting and complex family deserves better than this hasty<br />
attempt.<br />
McCarthy has provided two good, well illustrated α-taxonomic revisions. As will be seen below I do not<br />
agree with him in all details (mostly in regard to recognition of North American populations which consistently<br />
differ from his broader concepts). Thus I find Aptroot's comment in his review of McCarthy (1992) (Bryologist<br />
97: 467. 1994) most amusing: "However, the species concept applied is rather narrow and some specimens<br />
seem to represent transitional forms." I suspect that McCarthy's approach may well represent the mean<br />
between the lumper and the splitter and therefore be the most useful to the general lichenologist trying to<br />
name a specimen.<br />
For those who dislike change, the paper by Hafellner and Kalb is most unfortunate, not only in itself, but<br />
worse it has encouraged me to go even further in rearranging the Trichotheliaceae. They used the<br />
pigmentation of the ascomatal wall to divide Porina s. lat. into Porina and Pseudosagedia. These groups have<br />
been long recognized with varying degrees of clarity but mostly nomenclatural problems have led to the<br />
retention of a broad Porina. Hafellner and Kalb have cut the Gordian Knot. Below I have taken a different<br />
approach that essentially raises to the generic level the major groups recognized by Santesson (1952), uniting<br />
the P. nitidula group (Pseudosagedia) with Trichothelium, removing the P. phyllogena group to Strigula and<br />
adding a redefined Clathroporina. Amazing as it seems, this does not require the description of any new<br />
genera.<br />
Looking first at the taxa with blackish ascomata containing the pigment Pseudosagedia-violet, found in<br />
both Pseudosagedia and Trichothelium, the question is "Are setose ascomata a generic character?". I do not<br />
believe so. Hafellner and Kalb admitted there is an intermediate species with "bumps" on the ascomata (I<br />
commend their honesty, I wouldn't have known). The tendency to develop ascomatal appendages in<br />
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