PART 1
PART 1
PART 1
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multiseptate in Trichothelium. Ascomatal setae are confined to Segestria and Trichothelium. Clathroporina<br />
also differs in having more organized isidia, the ostiolar area is often black and there are no foliicolous<br />
species.<br />
The recognition of these four genera, Clathroporina, Porina, Segestria and Trichothelium, is somewhat<br />
analogous to generic segregation in Parmelia, distinctive in aspect (characters of the association) but ±<br />
uniform in characters of the asci and ascospores. I feel that the genera thus constituted have considerable<br />
predictive value regarding probable ascospore type, ecology and distribution. There seem to be four basic<br />
thallus/ascomata paradigms with rather continuous ascospore variation within each. This can be seen in the<br />
specific keys below where ascomata play only a small role. I simply do not understand the ascospore<br />
variation in the Trichotheliaceae. As pointed out by Aptroot and Sipman, it seems to encompass a different<br />
order of magnitude from that which mycologists are accustomed. In fact I consider this one of the distinctive<br />
features defining Trichotheliaceae. However, no one, myself included, has put the time and effort in to<br />
analyzing the situation. This leaves a situation where "species" are intuitively defined and one person's<br />
speculation is a good as another's. I consider my treatment below speculative at best and subject to<br />
considerable correction.<br />
Most of the species treated by McCarthy (1995) remain in Clathroporina under the new circumscription.<br />
Porina tahitensis (Räsänen) McCarthy and Clathroporina nuculastrum Müll. Arg. belong in Porina as defined<br />
here.<br />
Caribbean Porina firmula Müll. Arg. and P. subfirmula Riddle have very odd, placodioid thalli and may be<br />
considered for generic recognition. Two other species that may be referable to Segestria but are anomalous<br />
because of the pale pinkish ascomata and long, multiseptate ascospores and occur in eastern North America<br />
are an isidiate taxon reported from Long Island, New York reported by Brodo as Porina nucula (Porina sp. 4 in<br />
thesis), and a non-isidiate one from New Hampshire (Porina sp. 2 in thesis). I have not had time to reexamine<br />
the material, especially with regard to generic disposition, and as they are both very rare, I have<br />
decided to omit them here.<br />
KEY TO GENERA<br />
1. Ascomata usually small, essentially naked, with at most a thin covering of thallus<br />
(occasionally immersed in substrate); ascomata and thallus lacking oxalate<br />
crystals; ascomatal wall either some shade of red (Porina-yellow, Sagedia-red) or<br />
brown to blackish, often with blue or violet tones (Pseudosagedia-violet); some<br />
species with setose ascomata; muriform ascospores very rare; considerable<br />
diversity on leaves; distribution, except for foliicolous species, amphitropical .......................................... 2<br />
2. Ascomata blackish; wall often with blue or violet tints, without orange or<br />
red tints, KOH+ purplish or KOH-(Pseudosagedia-violet); with a very<br />
strong tendency for muitiseptate, elongate (even filiform) ascospores;<br />
setose species not uncommon........................................................................................ Trichothelium<br />
2. Ascomata reddish, sometimes darkening to black, lacking blue or violet<br />
tints, KOH+ more intensely orange or red (Porina-yellow); ascospores<br />
short, mostly 3-7-septate; setose species rare .......................................................................Segestria<br />
1. Ascomata usually rather large, surrounded by well developed thalline wart or<br />
immersed in thallus; wart and thallus containing oxalate crystals; ascomatal wall<br />
some shade of yellow or red (Porina-yellow); ascomata not setose; muriform<br />
ascospores not uncommon; few species on leaves; distribution essentially<br />
tropical and subtropical ............................................................................................................................. 3<br />
3. Black hypothallus lacking; thallus firmly attached to substrate, poorly<br />
organized, often verrucose; ascomata superficial, often somewhat constricted<br />
at base; few muriform-spored species; some follicolous species known; mainly<br />
species of open, drier? forest or scrub habitats, perhaps mainly subtropical ...............................Porina<br />
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