BOTANICAI. RESEARCH — MACDOUGAIv. I3I 



In a consideration of the subject of origin of new species many forms are 

 encountered in nature which exemplify quahties of two other species either 

 in a mosaic or an apparent intermediate grade in the ordinary taxonomic 

 sense. Such forms are usually taken to be hybrids, although nothing but the 

 actual resynthesis of the form by crossing the supposed parent or its culture 

 to show resolutions in successive generation may yield any actual evidence 

 upon the subject. 



An oak tree of this character growing on the farm of Mr. John Bartram 

 on the banks of the Schuylkill, some time previous to 1750, attracted atten- 

 tion as being of this hybrid character, and was named "Bartram's oak." 

 In recent years similar forms have been found in a wide range of localities, 

 the northernmost being Staten Island. The extended consideration of the 

 subject by systematists seemed to lend favor to the supposition that it was 

 a hybrid between Qnercus rubra (the red oak) and Q. phellos (the willow 

 oak). A number of acorns were procured from one of the trees on Staten 

 Island in October, 1905, and sprouted in the cultures in the New York 

 Botanical Garden. The resulting progeny, embracing nearly a hundred 

 plantlets, constituted the second generation of the hybrid and included a 

 series of forms which comprised individuals, some of which in this young 

 stage simulated the red oak, others the willow oak, while the remainder 

 showed various combinations of the parental characters. The origin and 

 nature of this form was thus definitely established, and it is without doubt a 

 hybrid product of the two oaks named. In conjunction with this work a 

 comprehensive description of methods of testing the constitution of supposed 

 hybrids has been formulated, and a list of reported hybrids incorporated in a 

 paper now in press. 



Hybridizations between Oenothera lamarckiana and O. rubrinervis, one of 

 its mutant derivatives, resulted in a progeny which in the first generation 

 split into the two immediate parents with no intermediates. 



Induction and Inheritance of Fasciations in Stems, by Miss A. A. Knox. — 

 Miss Knox, while assisting in the care of the cultures for the study of 

 heredity carried on by Dr. D. T. MacDougal in 1905 and 1906 at the New 

 York Botanical Garden, made an independent investigation of the causes, and 

 transmissibility from generation to generation of the banding or fasciation of 

 stems in evening-primroses. It was found in this work that the malformations 

 in question were due to injury in all cases examined. The injuries are caused 

 by larvae which hatch and feed on the growing tips, attacking the cells while 

 still in a meristematic condition. In most plants which are attacked the 

 growing region is destroyed or its vitality impaired, or the surrounding 

 leaves alone are consumed, the cells of the apex not reached, when no fasci- 

 ations result. Certain swarms of larvae by boring into the heart of the tip, 

 inflict delicate wounds which may induce fasciation. The occurrence of the 

 phenomena is dependent on three factors — the individual manipulation of 



