1894.] 



NATURAL SCIENCES OF PHILADELPHIA. 



165 



usually represented of a uniform tint of green, but the real artist 

 will tell us that there is seldom lacking a shade of brown or purple 

 in some portions of leaves and branches that are in the highest con- 

 ditions of vigor. The stronger growing shoots of the well-known 

 Pyrns japonica are always of a bright rosy brown, only in those 

 shoots growing in the interior of the plant, in partial shade, is the 

 brown tint wanting. lu the blood-leaved beech, the interior half- 

 starved leaves have little of the brown, and the more vigorous the 

 exposed branches are, the deeper is the shade. Blood- leaved trees 

 themselves are, on the whole, more vigorous than the normal green- 

 leaved forms frona which, in the language of the nurseryman, they 

 originally "sported." There is little doubt that in some unknown 

 way, a vigorous vital power is accountable for the blood-leaved char- 

 acter in these cases. 



A remarkable variation in the blood-leaved form of the common 

 white birch has recently occurred. Some twelve years ago, a small 

 plant was received from France. Some half a dozen were raised 

 from it by grafting on a closely allied species, Betula jjopulifolla. 

 From the ends of some of the lowermost branches in two of these 

 trees branchlets with the ordinary foliage of Betula alba have ap- 

 peared. The dark "red" or purplish brown color of the leaves 

 pervades the l)ark as well. In the reversion instanced not only the 

 leaves but the branches have 

 assumed the normal green. It 

 is interesting to note that the 

 reversion is not completed at 

 once. The dark color first 

 seems wanting in limited por- 

 tions of the bark as the growth 

 proceeds. At times the green 

 part widens, then again lessens 

 in length and width. In one 

 case the dark portion extends 

 as a hair line for four inches 

 upwardly before it finally dis- 

 appears. In one case half the 

 leaf is purple, the other half 

 green. There is no gradual shading oif of the green and the l)rown. 



