PART 1

MELANOMMATALES s. lat.
PYRENULACEAE Rabenh.
Since my treatment of Pyrenulaceae in eastern North America (Mem. New York Bot. Gard. 49: 74-107.
1989) and the preliminary treatment in "Some Florida Lichens", Aptroot has published a treatment of the
"peripheral" genera of Pyrenulaceae and Requienellaceae (Biblioth. Lichenol. 44: 1-178. 1991). Unfortunately
this work is flawed by numerous careless errors and poor observation. An extensive critique of the
morphological characters and cladistic results was published by Eriksson (Lichenologist 25: 307-311. 1993).
(From the point of view of a cladistic-know-nothing, Aptroot's errors, especially incorrect generic and familial
placements, would seem to make many of Eriksson's comments on the cladistic trees rather irrelevant.) In
spite of these problems much of the skeleton is sound and should not be discarded. Further, as a result of reexamining
some of the material studied by Aptroot, I have modified some of my ideas regarding the familial
placement of some of these genera. I had believed that the taxa with short, coarse, essentially unbranched
physes should be referred to the Requienellaceae. Restudy of hamathecial and ascal characters in Pyrenula
have led me to think that these are differences of degree and not kind. Requienella has a unique ascus type
with a "tholus" staining with various dyes (Boise, 1986). The taxa previously thought to belong to the
Requienellaceae also have rod-shaped microconidia, shorter than the filiform, often curved microconidia of the
Pyrenulaceae but, again, it seems to be a matter of degree. Requienellaceae sensu Aptroot seem to be nonlichen-forming.
I surmise this may be an adaptation to xeric habitats similar to Polymeridium in the
Trypetheliaceae. As a consequence I am restricting the Requienellaceae to Requienella, transferring the
other genera placed in the family by Aptroot to the Pyrenulaceae along with the resurrected genera,
Acrocordiella and Mycopyrenula. Another possibility, of course, would be to erect another family to
accommodate Distopyrenis, Granulopyrenis, Lachrymospora and Pyrenographa and possibly Acrocordiella
and Parapyrenis. The uniformly rod-shaped microconidia of the first four (not filiform as in Pyrenulaceae s.
str.) make this a tempting solution (microconidia not known for the last two). Perhaps adding to the confusion,
there are a wide variety of ascomatal types, pyrenuloid, parathelioid, pyrenastroid and possibly even
mycoporoid, none of which seems to align with ascospore type. There are so few specimens known it seems
best to more or less maintain the status quo pending more material and, perhaps, even molecular studies
which would seem useful in dealing with what seems to be a highly reduced group.
In 1989 when I abandoned ascomatal orientation and arrangement as generic characters, I did not
mention the case where many ascomata with apical ostioles are included within a pseudostroma filled with
pigment and/or oxalate(?) crystals. This type is very common in the Trypetheliaceae but very rare in the
Pyrenulaceae. To repair the previous omission two such taxa are included below although neither is reported
from Florida, P. concastroma and P. wrightii.
KEY TO GENERA OF PYRENULACEAE AND REQUIENELLACEAE
1. Ascomata perithecioid............................................................................................................................... 2
2. Ascospores some shade of brown, mostly thick walled........................................................................ 3
3. Ascospores 4-celled to muriform; physes long and slender
(except in Acrocordiella and Mycopyrenula which have 4-celled
ascospores and are non-lichenized) ................................................................................................ 4
4. Lichenized; thallus usually conspicuous........................................................................................ 5
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