land 



1234 The Trees of Great Britain and Ire 



Q. nigra, two species which have often lobed leaves on young trees and on vigorous 

 barren branchlets of older trees. In these species the petioles are inconspicuous, 

 or merely i to 2 lines long. Q. imbricaria, which has long petioles, is readily 

 distinguished in all its forms and hybrids by the pubescent leaves. 



This oak was first described from a solitary tree ^ growing on the farm of John 

 Bartram, near Philadelphia, on the banks of the Schuylkill, where it was discovered 

 at some time previous to 1 750. What appears to be the same tree has since been 

 discovered at a considerable number of stations^ from New Jersey to Texas. 



Much discussion has arisen as to the relationship of Bartram's oak, and of the 

 individuals that have been found like it ; and Engelmann, who had not, however, 

 seen flowers or fruit, considered it to be a distinct species, and not a variety of 

 either Q. Phellos or Q. nigra, nor a hybrid of any of these oaks. The hybrid origin 

 of Q. heterophylla was, however, definitely settled by an experiment of Dr. D. T. 

 MacDougal.^ In October 1905 he collected seventy-five acorns from a tree growing 

 on Staten Island, which had foliage similar to that of Bartram's oak ; and fifty-five 

 seedlings were obtained, which exhibited foliage of three kinds. Some of the seed- 

 lings had lanceolate entire leaves like those of Q. Phellos ; others had broad lobed 

 leaves like those of Q. rubra, while the remainder were intermediate and resembled 

 the parent tree. In this case the parents may be assumed to be Q. Phellos and 

 Q. rubra ; * but in other cases, though one of the parents is almost certainly 

 Q. Phellos, the other, judging from the fruit, may be Q. coccinea or Q. velutina. 



This oak appears to be very rare in cultivation, the only specimen which we have 

 seen in England being the tree at Kew, mentioned above. Loudon says : " Said 

 to have been introduced, but we do not know where it is to be obtained." 

 Older trees, bearing this name, are usually Q. Leana. There is, however, a large 

 tree of Q. heterophylla at Les Barres,^ about 66 ft. by 9 ft., which bears fruit 

 regularly, but in small quantity, and is said to be very hardy. This tree was 

 planted' in 1822. Another tree at Verrieres,' probably of the same origin, but with 

 slightly different foliage, measures Ti ft. by 8 ft., and bears a tuft of mistletoe on 

 one of its large branches. /A. H.) 



1 Otto of Berlin, in Loudon, Card. Mag. xvii. 380 (1841), states that he saw Q. heterophylla, a tree 40 ft. high, growing 

 m Bartram's botanic garden at Philadelphia, which was founded ini;!;. 



,„ ,' otc?"^'^'^ ""'""^ °^ *^ occurrence of these trees is given by Arthur Hollick, in Bull. Torrey Bot. Club. xv. 

 303 (loos). 



3 Cf. Bot. Gaz. xliii. 49, figs. 2, 3 (1907). Mechan, in Card. Chron., 1866, p. 365, speaks of two seedlings from the 

 ongmd tree, one a perfect Q. Phellos, the other like Q. heterophylla. ^ ^ 3 f S 



6* % f^'^f "> S^''°"'3«^ toe. cil., who attempts to divide this form into three sub-varieties. 



Ct. i-ardg, Arb. Nat. des Barres, 299 (1906). 

 « Hortus Vilmorinianus, 55 (1906). A specimen branch procured by Elwes shows imperfect acorns. 



