4o8 RESEARCHES ON FUNGI 



former fungus appears to be adapted to carry on its functions at a 

 somewhat lower temperature than the latter. 



Evidence Proving the Existence of Luminous and Non-luminous 

 Forms of Panus stypticus. — The fruit-bodies of Panus sUjpticus 

 gathered in North America resemble morphologically those gathered 

 in Europe ; and, so far as their structure is concerned, there seems 

 to be no justification for regarding them as belonging to two dis- 

 tinct forms. Yet physiologically, as already stated in an earlier 

 Section, the North American fruit-bodies differ from the European, 

 for the North American fruit-bodies are luminous, whereas the Euro- 

 pean ones are not. Hence, following precedents in treating of the 

 taxonomy of the Rust Fungi, Bacteria, etc., I have divided the 

 species Panus stypticus into two physiological forms : P. stypt. 

 luminescens occurring in North America, and P. stypt. non-lumines- 

 cens occurring in England.^ 



The evidence which goes to show that the North American 

 strains of Panus stypticus are luminescent, whereas the European 

 strains are non-luminescent, is as follows. 



(1) The bioluminescence of Panus stypticus was first observed in 

 North America and has never been recorded in Europe. 



(2) In North America the bioluminescence of Panus stypticus 

 has been observed : [a) by Atkinson ^ in fruit-bodies presumably 

 collected near Cornell University, Ithaca (New York State) ; 

 (6) by Bisby ^ in fruit-bodies attached to a stump in a wood near 

 MinneapoHs (Minnesota) ; and (c) by myself in fruit-bodies collected 

 at Montreal (Quebec),'* Ottawa (Ontario), Toronto (Ontario), Ann 

 Arbor (Michigan), and St. Paul (Minnesota). ^ 



(3) In England the absence of bioluminescence in fruit-bodies of 

 Panus stypticus has been observed : {a) by myself, in 1910, in fruit- 

 bodies collected by W. B. Grove near Birmingham ; ^ [h) by Miss 



1 CJ. pp. 365-366. 



2 G. F. Atkinson, Studies of American Fungi, Mushrooms, edible, poisonovs, etc., 

 Ithaca, U.S.A., 1901, p. 136. 



3 Cf. p. 376. * CJ. p. 364. 



5 Cf. p. 384. The Ann Arbor and St. Paul fruit-bodies were tested twice, 

 once with collections made in 1921 and a second time with collections made in 

 1923. 



« Cf. p. 365. 



