The genera Aecidium, Uredo and Puccinia of Persoon

According to the International Code of Botanical Nomenclature, Art. 23, the nomenclature of the Uredinales, Ustilaginales and Gasteromycetes begins with Persoon’s “Synopsis Methodica Fungorum”, published in 1801. His descriptions, however, are partly not very explicit and as, according to the Code, Art. 69, rust names are valid solely in so far as they refer to “spores giving rise to basidia”, i.e. the teleuto-stage, the present author found it desirable to examine Persoon’s collection of rusts preserved in the Rijksherbarium, Leiden. Through the courtesy of Dr. R. A. Maas Geesteranus, Mycologist of the Rijksherbarium, all specimens of the genera Aecidium, Uredo and Puccinia were lent to the Botanical Museum of the University of Oslo, where the author got the opportunity of examining them. The collection contained 792 numbers, comprising 221 species of rusts, 19 species of smuts, and 14 species of other fungus groups. A complete list of determinations is filed in the Rijksherbarium. The main aim was to find suitable lectotypes for Persoon’s taxa of 1801, among specimens containing teleuto. And owing to the type method now being established (Code, Art. 18) it seems natural to consider a Uredo name valid if the type contains teleuto, even if this stage has not been mentioned in the author’s description of the species in question (cp. D. P. Rogers, Mycologia, 45 pp. 250—251, 1948, and D. B. O. Savile, Canadian Journ. Bot., 3 p. 490, 1955). This view makes Persoon’s names Uredo betae and U. viciae-fabae valid. However, most of the specimens had clearly been collected after 1801 and were consequently unsuitable as material for lectotypes. This younger material contains many species that are not mentioned in Syn. Meth. Fung. and consequently not treated in the present publication. For the taxa established by Persoon in 1801 have particularly been taken into consideration those specimens that in Persoon’s handwriting are solely furnished with the same name (or sometimes with a somewhat differing one) as in Syn. Meth. Fung. and without author name, or sometimes with Persoon’s own. Most of the other specimens of the same taxa are also labeled solely or partially by Persoon, but have not been taken into consideration as material for lectotypes because the names do not correspond with those in Syn. Meth. Fung., or are obviously younger than 1801 (e. g. if published by De Candolle, Link, or other contemporary authors). Many of these specimens Persoon had received from other botanists, particularly Chaillet, Balbis, and Mougeot. Only one specimen presumably older than 1801 is mentioned as having been received from another person, viz. Smith (presumably J. E. Smith in England); it is labeled Uredo linearis β. Polypodii and contains Hyalopsora polypodii (Diet.) Magn.