Apr. 1907] PROCEEDINGS s. I. ass'n x\rts axd scien'ces. 117 



had beg-un to receive the critical attention that has recently been given 

 to it. 



At that time the question of the hybrid origin of 0. heteropliylla was 

 yet open to discussion, but Mr. Davis and Dr. Arthur Hollick both 

 declared their conviction that it must be a hybrid with the willow oak, 

 Q. PhcIIos L., as one of the parents. The identity of the other parent 

 remained in doubt for some time, but Dr. Hollick finally concluded' 

 that it was the red oak, O. rubra L. {Bull. Torrey Bot. Club, vol. xv, 

 Dec. 1888, pp. 308, 309), and in this connection the following discus- 

 sion and conclusion by Dr. Mac Dougal, on pp. 50, 51, are both inter- 

 esting and gratifying: 



"About 75 acorns * * * were placed in the propagating houses of 

 the New York Botanical Garden, with the result that 55 plantlets were 

 available for study in December and January following. With the 

 formation of the earliest leaves it became evident that a wide diversity 

 of form of these organs and other qualities prevailed, as shown by the 

 photograph taken in April [fig. 2] . 



"In May 1906 all of the plantlets were transferred to the experimental 

 grounds, and as the development proceeded the diversity became still 

 more marked. At the close of the season it could be seen that this 

 group of plants included some which simulated Q. Phellos with its 

 lanceolate entire leaves, wdiile others were not separable from O. rubra, 

 the remainder being capable of arrangement in a series between these 

 two poles. An examination of the literature disclosed the fact that 

 the combined observations of the several botanists who have written 

 on the subject refer to plants bearing almost the entire range of leaves 

 noted in the cultures here described. In most of these accounts the 

 leaves are said to be much like those of Q. Phellos, while some obser- 

 vations include notices of others which were broad lobed and notched, 

 although most of these writers were extremely chary of identifying 

 any of the forms with those of Q. rubra. It is to be noted, however, 

 that as a result of the consideration of gross anatomical facts and dis- 

 tributional data. Dr. Hollick and other botanists had finally concurred 

 in the general conclusion that the tree was in all probability a hybrid 

 between the red oak and the willow oak. 



"With our present available information concerning the behavior of 

 hybrids this conclusion seems unavoidable * * * some of the individ- 

 uals include so many of the qualities of the red oak and willow oak 

 that the evidence is overwhelmingly in favor of the conclusion that the 

 origin of O. heierophylla is to be attributed to the hybridization of 

 these two forms." A. H. 



