IRbobora 



JOURNAL OF 



THE NEW ENGLAND BOTANICAL CLUB 



Vol. 6 March, 1904 No. 63 



PARTIAL REVERSION IN LEAVES OF THE FERN- 

 LEAVED BEECH. 



R. G. Lea V ITT. 



The European beech, Fagus syJvatica, has produced a number of 

 varieties, of which several are in cultivation. These forms have 

 almost surely originated by sudden saltatory changes; that is, by muta- 

 tion. The varieties differ from the species in one or more characters 

 which — at least in several of the varieties — may be transmitted by 

 seed. The well-known purple beech is one of these ofTshoots from 

 the specific stock. The original tree was discovered in Germany 

 between the middle and the end of the eighteenth century, according 

 to some, and in Loudon's day was said to be still standing. Accord- 

 ing to Loudon all the purple beeches cultivated in Europe in his time 

 had been produced from this tree either by seed or by grafting. The 

 seedlings come up tolerably true. Other varieties are F. s. pendula, 

 F. s. cristata — the leaves small and tufted, the wood dark and curi- 

 ously grained — and i^ j-. asplenifoUa. The last named form, upon 

 which some observations are made below, according to De Vries 

 may be propagated by seed. It differs from the species in having 

 narrowly elliptical or lanceolate leaves, variously cut, while the leaves 

 of the species are, as a rule, broad and almost or quite entire. This 

 form has originated, with little doubt, by mutation from the older 

 type. Such "sports" are of special interest to students of evolution 

 for the light they may possibly throw upon evolutionary processes. 



One of the chief problems to be solved in working out the origin of 

 species is whether new races arise by the accumulation of slight vari- 

 ations, or whether the alterations are more violent and sudden, so 

 that new species are abruptly created with differentiating characters 



