334 



NATURE 



[June 26, 1919 



state, are intermediate in botanical characters between 

 an American and a European species in each case, 

 and are undoubtedly first-crosses. 



The origin and history of the London plane, 

 Platantis acerifolia, form the subject of a paper by 

 Prof. Henry which appeared in the Proceedings 

 of the Royal Irish Academy for April last. This tree 

 has all the peculiarities which are met with in a 

 first cross. It is intermediate in fruit and in leaves 

 between the supposed parents, the Oriental plane, 

 which is indigenous in Greece and Asia Minor, and 

 the Occidental plane, which grows in a wild state in 

 the forests of the eastern half of the United States. 

 Its vigour is exceptionally great, as is usual in hybrids 

 of the first generation ; and its seeds when sown 

 produce a mixed and varied crop of seedlings, in 

 which are variously combined the characters of the 

 two parents. Several supposed forms of the London 

 plane, which are not uncommonly cultivated, appear 



Fig. I. — Flatanus orientalis. From Thermopylae seed. 



to be chance seedlings of this tree, being hybrids of 

 the second generation. 



The London plane is extensively used for 

 planting in the streets of towns of Europe 

 and North America, as it has been found to 

 surpass all other trees in its powers of resistance to 

 drought, smoke, and other unfavourable conditions of 

 soil and atmosphere. In the cities of New England, 

 Ohio, Pennsylvania, etc., the London plane is much 

 more successful as a street tree than the Western 

 plane, notwithstanding the fact that the latter is the 

 finest and largest native broad-leaved tree in the 

 forests of these States. The selection as a street tree 

 of the London plane in preference to the native species 

 in the regions' where the latter flourishes depends on 

 the vigour inherent in the former tree on account of 

 its hybrid origin. 



The London plane, being undoubtedly a hybrid, 

 must have originated as a chance seedling in some 

 botanic garden where an Occidental plane and an 



NO. 2591, VOL. 103] 



Oriental plane happened to be growing close together. 

 Such a seedling, by the vigour of its growth and the 

 novelty, of its foliage, would attract attention arid be 

 propagated by an observant gardener. The ease with 

 which the London plane can be raised from cuttings 

 would much facilitate its propagation. Prof. Henry 

 shows that it possibly originated in the Oxford 

 Botanic Garden about 1670, though this surmise 

 cannot be definitely proved. 



The Occidental plane was introduced from America 

 into England by Tradescant in 1636, about a century 

 jater than the earliest record of the Oriental plane 

 in this country. By 1670 there would have been trees 

 of the American species old enough to bear pollen. 

 The connection with Oxford is as follows :— Jacob 

 Bobart, jun., who succeeded his father as curator of 

 the botanic garden at Oxford in 1680, left in MS. 

 "An Enumeration of Trees and Shrubs," in which 



Fig. 2.— Flatanus occidentalis . 



for the first time there is mention in any record of 

 the London plane. This MS. is, unfortunately, with- 

 out date, but a similar MS. has 1666 on the fly-leaf. 

 In the " Enumeration " the planes in cultivation are 

 distinguished as follows : — 



No. 475. Flatanus orientalis, pilulis amplioribus. 



No. 476. P. inter orientalem et occidentalem media. 



No. 477. P. occidentalis aut virginiensis. 



Corresponding with the diagnosis. No. 476, of the 

 London plane, as intermediate between the Oriental 

 and the Occidental species, there is a dried specimen, 

 undoubtedly P. acerifolia, in the Sherard Herbarium 

 at Oxford labelled " Platanus media." 



The first published description of the London plane 

 was by Plukenet in 1700 in his "Mantissa" (p. 153), 

 which reads as follows : — " Platanus orientalis et 

 occidentalis mediam faciem obtinens, Americanus, 

 globulis grandioribus, foliis splendentibus atris." 

 The type-specimen of this description is in the British 

 Museum, Herb. Sloane, No. loi, folio 112. In addi- 



