134 Rhodora [JuLY 
predilection for living or dead trees, stumps and mossy logs, the plants 
of western America are certainly specifically inseparable from the 
endlessly variable P. vulgare of Europe. Their ranges on the two 
continents are so strikingly similar to those of Blechnum Spicant (L.) 
Sm. (western Eurasia, north Africa and the Atlantic Islands; southern 
Alaska to California) and Equisetum maximum Lam. (E. Telmateia 
Ehrh.) (western Eurasia, north Africa and the Atlantic Islands; 
British Columbia to southern California) that absolutely no violence 
is done the probabilities of truth by treating them as one species; 
and, until they are shown to have stronger characters than their 
supporters have yet pointed out, it would seem only the part of sound 
classification so to treat them. Diels has expressed almost this 
conclusion by saying, “ P. californicum Kaulf. (pacifisches Nord- 
amerika) kommt dem P. vulgare L. so nahe, dass es nur durch die 
(noch dazu nicht überall constante) Maschenbildung davon zu trennen 
ist" ;! Schur, describing the European P. vulgare, var. transsilvanicum 
made the note: “An P. vulgare, var. occidentale Hook”; Eaton, 
describing P. californicum, var. intermedium, practically admitted 
that he could not separate it from the European P. vulgare, var. 
serratum; Hooker & Baker gave up the attempt to keep P. falcatum 
distinet from European forms of P. vulgare; and Maxon, in publishing 
P. hesperium as a species, suggested the possibility “that the species 
here described is identical with the var. rotundatum [of P. vulgare] of 
Milde." 
Neither Blechnum Spicant nor Equisetum maximum extend east- 
ward far beyond the limits of Europe. It is, therefore, significant 
to note Hooker’s statement? of the Eurasian range of Polypodium 
vulgare: “Europe, to its extreme south; North Africa, Madeira, 
Canaries, and Azores . . . ; Siberia, the Amur, Manchuria, 
Japan (unknown in the tropical continent of Asia, or even in the 
Himalaya). From Erzeroum, Asiatic Turkey, I possess specimens. ” 
In other words, except from an indefinite "Siberia," the species 
was not known to Hooker from between Europe and adjacent Asia 
Minor and “the Amur, Manchuria, Japan." Ledebour, in Flora 
Rossica,‘ cites Siberian material only from the Ural (on the Russian 
1 Diels in Engler & Prantl, Pflanzenf. i. Ab. 4: 312 (1899). 
2 Schur, En. Pl. Transsilv. 830 (1866). 
3 Hook. Sp. Fil. iv. 205 (1862). 
4 Ledeb. Fl. Ross. iv. 508 (1853). 
