Fink: Nature and Classification of Lichens 255 



group with as distinct ordinal and family characters as those 

 found in any other groups of plants. Classification is a means to 

 an end. The most useful ends of classification are: (i) Identi- 

 fication of species described and studied by various persons, 

 (2) association of morphological and physiological ideas con- 

 cerning various plants into useful units of thought. These ends 

 are most helpfully met for me, by maintaining lichens as an 

 independent group. I take it that the real crux lies in my last 

 point. There is of course no possible phylogenetic relation be- 

 tween Ascolichenes and Basidiolichenes. It becomes finally a 

 choice between the convenience to the student of emphasizing such 

 difference in origin or of emphasizing the many points of re- 

 semblance between all lichens. I prefer the latter. Morpholo- 

 gist, 1- 2 (i 2 ). 



Quotation 25 



Had we used strict logic, according to the usual procedure 

 elsewhere in systematic Botany, each independent component of 

 the lichen thallus — algae as well as fungi — would have its allotted 

 place near those organisms with which it appears most closely 

 related. But the needs of the lichen-taxonomist are not satisfied 

 in the least by this arrangement. Also the breaking down of 

 this biological group would be very unfavorable for those in- 

 vestigators who study this interesting group, the lichens, in their 

 anatomical, physiological or geographical relations. Because of 

 these considerations I answer your questions as follows : ( 1 ) Yes. 

 (2) The lichens should be maintained as a special, biological 

 class. To complete the fungus-system, the genera of the lichen- 

 fungi should, at least, be mentioned among the orders of the 

 fungi. Biologist, 2, 8, a- (i 2-8 ).* 



* Verfahrt man streng logisch, nach den sonst in der Systematik iibligen 

 Gepflogenheiten, so hat selbstverstandlich jede Komponente des Flechtenthallus 

 — Algae wie Pilz — ihren im System anzuweisenden Platz neben denjenigen 

 Organismen, mit denen sie am nachsten verwandt erscheint. Damit ist aber den 

 Bediirfnisen des Flechtensystematikers nicht im geringsten geniigt. Auch fur 

 die jenigen Forscher, welche die so interessante Gruppe der Flechten in anato- 

 mischer, physiologischer, geographischer Beziehung studieren, ware die Auf- 

 losung dieser biologischen Gruppe sehr unvorteilhaft. Auf Grund dieser 

 Erwagungen beantwortete ich Ihre Fragen folgendermassen : (i) Ja. (2) Die 

 Flechten sind als besondere biologische Klasse aufrecht zu erhalten. Zur 

 vervollstandigung des Pilzsystems sind die Gattungen der Flechtenpilze bei den 

 Ordnungen der Pilze wenigstens zu erwahnen. 



