PLATANUS 



PLATANUS 



2707 



palmately lobed leaves and small greenish flowers in 

 drooping heads, followed by similar heads of fruits 

 remaining on the branches during the winter. The 

 smooth light-colored often almost creamy white bark 

 of the branches and limbs, usually mottled by darker 

 blotches of the older bark, which peels off in large thin 



3061. Platanus racemosa. 

 (Xjfl 



plates, gives the tree a very characteristic appearance 

 in winter, while in summer the plane-tree, with its 

 large head of dense bright green foliage and with its 

 massive trunk is a beautiful and majestic shade tree. 

 The native P. occidentalis is hardy North and P. aceri- 

 folia and P. orientalis hardy as far north as Massa- 

 chusetts, while the southwestern and Mexican species 

 cannot be cultivated in the North. From time imme- 

 morial, the oriental plane, which was well known to the 

 ancient Greek writers, has been famous for the large 

 size it attains trunks of 30 feet in diameter and more 

 are reported to exist and has been planted as a shade 

 tree in western Asia and southern Europe, and today it 

 is still one of the favorite street trees throughout the 

 temperate regions of Europe. It has also been recog- 

 nized in this country as one of the best street trees, 

 even to be preferred to the native plane, which, unfor- 

 tunately, suffers from the attacks of a fungus, Gteo- 

 sporium nervisequum, while the oriental is not injured by 

 it. The plane-trees stand pruning even severe prun- 

 ing well. To what extent they are sometimes pruned 

 in European cities without losing their vitality is 

 shown in an interesting illustration in "Forest Leaves," 

 Vol. Ill, p. 97. They are also easily transplanted even as 

 larger trees. They grow best in a deep and rich moist 

 soil. Propagation is by seeds sown in spring and only 

 slightly covered with soil and kept moist and shaded; 

 also by cuttings of ripened wood and by greenwood 

 cuttings under glass in June taken with a heel, and some- 

 times by layers. Varieties are also sometimes grafted in 

 spring on seedlings of one of the species. The stellate 

 hairs of the young leaves when detached by the wind, 

 sometimes float in great quantities in the air and are 

 liable to cause irritation and sometimes inflammation 

 of the mucous membranes of the eye, nose, and mouth. 

 But as this is likely to occur only during a very limited 

 period late in spring it can hardly be considered as a 

 serious objection to the use of platanus as a street tree. 



A. Fr. -heads 3 or more, in pendulous racemes. 

 B. Lobes 5-7, dentate or lobed. 



orientalis, Linn. ORIENTAL, PLANE. Tree, to 80 ft., 

 with usually very broad and round head on a compara- 

 tively short trunk: bark of dull grayish or greenish 

 white color: stipules small, usually with entire margin: 

 Ivs. usually broadly cuneate at the base, deeply 5-7- 

 lobed, rarely 3-lobed, with the sinuses reaching almost 

 to or below the middle; lobes longer or much longer 

 than broad, coarsely toothed or entire, glabrous or 

 nearly so at maturity, 4-8 in. long: fr .-heads 2-4 on long, 

 drooping stalks, bristly, the nutlets narrowed at the 

 apex into a persistent style to 2 lines long. May. S. E. 

 Eu. to India. G.F. 4:91. G.C. III. 23:25, 27; 29:363. 

 Gn. 1, p. 550; 20, pp. 369, 371, 373. F.S.R. 2, pp. 75, 77. 

 F.E.24:69. G.W. 14, pp. 688, 689. Var. digitata, 

 Janko (P. umbraculifera, Hort., var. laciniata, Hort.). 

 Lvs. cuneate or truncate or cuneate at the base, deeply 

 5-lobed, with narrow, elongated, coarsely toothed lobes. 

 Gn. 1, pp. 572, 573; 20, p. 371. F.E. 18, p. 718, pi. 89. 

 Var. cuneata, Loud. (P. cuneata, Willd.) . Often shrubby : 

 Ivs. short-stalked, smaller, usually deeply 3-lobed and 

 cuneate, with narrow-toothed lobes. Gn. 1, p. 618; 

 20, p. 371. G.C. III. 29:363. The true oriental plane 

 is rare in cult., the tree usually planted under this name 

 being P. acerifolia. 



BB. Lobes S-o, usually entire. 



racemdsa, Nutt. (P. calif ornica, Benth.). Fig. 3061 

 (adapted from Pacific R. R. Report). Tree, to 100 or 

 120 ft., with a trunk often divided into several sts. : Ivs. 

 usually cordate or truncate, deeply 3-5-lobed, thick 

 and firm, deep green above, paler beneath and covered 

 with a pale tomentum, 6-10 in. diam.; lobes ovate- 

 lanceolate, entire or sometimes remotely, or sinuately 

 toothed: fr.-heads bristly or rather smooth, sessile, 2-7; 

 nutlets tomentose while young, becoming glabrous. S. 

 Calif, and Low. Calif. S.S. 7:328. 



AA. Fr.-heads 1 or 2, rarely 3. 



acerifolia, Willd. (P. orientalis var. acerifolia, Ait. 

 P. intermedia, P. integrifolia and P. macrophytta, Hort. 

 P.damascena, Dode). LONDON PLANE. Fig. 3062. Prob- 

 ably hybrid between P. orientalis and P. occidentalis and 

 intermediate between the two, sometimes resembling 



3062. Platanus acerifolia. ( x about 



more the one and sometimes more the other parent. Tree, 

 to 100 ft. : Ivs. 3-5-lobed, usually truncate or broadly cu- 

 neate at the base, the lobes broadly triangular, coarsely 

 toothed, the middle lobe as long or slightly longer than 

 broad : fr.-heads usually 2, rarely 3, bristly or sometimes 

 scarcely so. Of garden origin. G.C. III. 29:363. Gn. 1, 

 p. 588; 20, p. 371 and probably 1, p. 486, and 20, p. 370 

 (as P. occidentalis). F.E. 24:69 (as P. orientalis). Var. 



