376 Rydberg : Notes on Rosaceae 



type of Quinquefolium Tourn. the type of Potentilla L. The plant 

 figured by Tournefort is Potentilla reptans L. Tournefort had 

 adopted the name Quinquefolium from Caspar Bauhin.* The 

 latter referred directly to the Pentaphyllon (irevTafyvWov) of Dios- 

 corides and Theophrastus and Pliny's Quinquefolium, all evidently 

 the official plant Potentilla reptans. The plate in Dioscorides 

 (Codex Vindobonensis, of which there is a photographic fac- 

 simile copy in the library of the New York Botanical Garden) 

 may very well represent P. reptans, or at least a species of Poten- 

 tilla with digitately 5-foliolate leaves, 5 petals, and decumbent 

 stem, rooting at the nodes. 



A few botanists are inclined to regard the first species men- 

 tioned as the type of the genus. The first species of Potentilla 

 is P. fruticosa L., but this was not a part of Tournefort's Quin- 

 quefolium. The first Tournefortian species of that genus, cited 

 by Linnaeus, is P. recta, and the first Linnaean species given in 

 Tournefort's Institutiones, is P. alba; but neither of these agrees 

 with Tournefort's plate, nor can they be traced back to the old 

 Greek and Latin writers, from whom Tournefort adopted the name 

 Quinquefolium. There is therefore no species which can dispute 

 the right of P. reptans as being regarded as the type of Potentilla, 

 except P. Anserina, and the latter can do so only if we admit a 

 pre-Linnaean starting point of our nomenclature. 



The type of Tormentilla L. t is T. erecta L., or Potentilla Tor- 

 mentilla, a 4-merous species of the same group as P. reptans. 



The type of Quinquefolia (Tourn.) Adans. % and of Pentaphyl- 

 lum Gaertn.,§ is of course also P. reptans. The proposing of 

 another genus Callionia Greene || was, of course, altogether super- 

 fluous, for its type. Potentilla canadensis L., is so closely related 

 to P. reptans that no scientist would seriously think of placing 

 them in different genera. In proposing Callionia, the author 

 says: "If Argentina be separated from Potentilla, it is by habit 

 and inflorescence alone and from this there seems to follow neces- 

 sarily the conceding of equal rank to what I shall call Callionia." 



*Pinax 325. 

 tSp. PI. 500. 1753- 

 JFam. PI. 2: 295. 1763. 

 *.Fruct. 1: 349- 1788. 

 |ILeaflets 1: 238. 1906. 



