OF THE EASTERN UNITED STATES 381 



two rows of cells wide and 4-7 cells high. The base of each balloon- 

 shaped gland stalk is surrounded by 16 somewhat elongated cells ar- 

 ranged in radial fashion. Simple unicellular trichomes also occur in 

 large numbers on this surface and along the margin. The base of each 

 is sclerified and elevated in papillar fashion above the epidermis. No 

 bowl-shaped glands occur on either surface of the leaf. The average 

 width of the lamina outside of the mid-rib is 168.96 n. 



Myrica Macfarlanei, Youngken. 



The microscopic characteristics of the leaf of this hybrid are inter- 

 mediate between those of its parents. For instance: — the upper epider- 

 mis is composed of cells whose vertical walls are more curvilinear than 

 M. cerifera, less curvilinear than M. Carolinensis. Their mean dimen- 

 sions in surface view are 26.7 yu x 16.89 ^u. Their outer walls are less 

 projecting than those of M. cerifera, more so than M. Carolinensis. 

 The cuticle is thinner than that of M. cerifera, thicker than that of M. 

 Carolinensis. The palisade region of the mesophyll is 3-4 layers wide 

 and so is intermeditate between this region in M. cerifera and M. Carolin- 

 ensis {vide supra). The lower epidermis consists of cells whose vertical 

 walls are more curvilinear than those of M. cerifera, less curviUnear 

 than those of M. Carolinensis. The mean dimensions of these cells 

 in surface view are 26.46 /x xl3.59 n which is likewise an intermediate 

 character. The stomata are fewer in number than on M. Carolinensis, 

 more numerous than on M. cerifera. The upper surface shows a scatter- 

 ing of orange-red bowl-shaped glands and golden-yellow balloon-shaped 

 glands, or sometimes the latter only. The lower epidermis shows 

 numerous orange-red bowl-shaped and golden-yellow balloon-shaped 

 glands, both of which are often fewer than on the similar epidermis of 

 M. cerifera. The tendency for the head of the bowl-shaped gland in 

 the hybrid to become saucer-shaped is very striking. Simple unicellular 

 trichomes and the sclerotic bases of these are common on both lower and 

 upper epidermis, but intermediate in number between those on the 

 leaves of the parents. Finally, the average thickness of the lamina 

 of the hybrid outside of the mid-rib is 201.6 /x while that of M. cerifera 

 is 268.8 /i and of M. Carolinensis, 168.96 fx. 



Myrica Gale, L 

 The upper epidermis is composed of a layer of polygonal cells with 

 rectilinear to very slightly curvilinear external walls. It shows here 

 and there stomata which are fewer than on the lower epidermis. The 



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