46 Rhodora [March 



fully formed. It is certain that now and again new races do appear 

 suddenly. Many of them come reasonably true to seed ; and in this 

 fact lies an argument for the stability of the new forms. Neverthe- 

 less the period during which such matters have been subjects of 

 inquiry is not long. What the results of protracted breeding experi- 

 ments may be is as yet problematical. Granting that the newly 

 appearing, or as they are called mutational, characters have a certain 

 force as hereditary factors, it is yet to be ascertained whether the 

 races produced by mutation do not of themselves ultimately return to 

 the "normal," or original, type. If we conceive that the change of 

 outward characters which signifies the occurrence of a mutation is 

 the visible expression of an inversion or derangement of the constitu- 

 ents of the complex substance controlling the development of form, 

 and in reproduction serving as the vehicle of hereditary traits, then 

 it seems possible that after a time these constituents may regain their 

 previous, or normal, arrangement and in consequence the original 

 external characters be restored.' 



The tendency of Fagus sylvatica asplenifolia to revert in certain 

 parts is well known. De Vries speaks of frequent atavistic bud 

 variation."^ Carriere ^ figures a young shoot on one side of which all 

 the branches bore exclusively leaves of the specific form. A tree 

 growing at North Easton, Massachusetts, has manifested a still 

 further localized and restricted resumption of original characters. 

 Atavism has appeared not in one branch, or one bud, but in a part 

 of a leaf, in many instances. In most cases about one quarter to one 

 third of the lamina was thus affected, usually in the proximal part, 

 occasionally in the distal, on one side or other of the midrib. These 

 leaves were unsymmetrically developed, as will be seen from the 

 accompanying figure, through overgrowth of particular regions of the 

 blade. The unusual portions had entire or at most somewhat den- 

 tate margins. When the blades were applied to blades of the same 

 length taken from the species, so that bases, apices, and midribs 

 coincided as nearly as possible, the margins of the overgrown parts 



' Students of our native flora may render good service to science by reporting 

 and descriliing aberrant forms and by cultural experiments. Careful notes con- 

 tributed to botanical journals would be of much value. Careful and full records 

 of how the new or unusual forms behave in prolonged vegetative reproduction, 

 in ]3ropagation by seed after pollination by their own pollen and after cross-polli- 

 nation with the normal forms, are especially desired. 



^ De Vries, Die Mutationstheorie, i: 488. 



^Carriere, Production et Fixation des Varietes (Paris 1865), p. 49. 



