OF THE EASTERN UNITED STATES 387 



tirely covered over by that substance. Apex of mature fruits, aceri- 

 ferous. Two-hundred fruits which the writer gathered at Palermo, 

 N. J. November 7, 1914 weighed 2.86 gms. Fruits of one season past 

 alone adhere to the axes of the catkins. 



M. Carolinensis, Miller 

 Fruits larger than those of M. cerifera, spherical , tomentose hairy 

 in their young condition, covered over early, as those of M. cerifera by a 

 thick exudation of wax, traversed at maturity by a portion of the per- 

 sistent hairs and having a diameter of 3. 5-4. 5mm. Apex of mature 

 fruits, ceriferous. Two hundred fruits which the writer gathered at 

 Palermo, N. J. November 7, 1914 weighed 9.27 Gms. The fruits of 

 two seasons past adhere to the persistent catkin axes. 



M. Macfarlanei, Youngken 



Fruits intermediate in size, apex, weight and duration between those 

 of M. cerifera and M. Carolinensis, having a diameter of 3-4 mm. Apex 

 of mature fruits pitted. Two hundred fruits which the writer gathered 

 at Palermo, N. J. November 7, 1914 weighed 6.7 Gms. The fruits 

 of one season past and several of the previous season adhere to the per- 

 sistent catkin axes. 



Careful study has been made by the writer of stages in the develop- 

 ment of the fruits of the above types. These will be described as one 

 category seeing that they closely agree with each other. 



In early June the maturing wall of each ovary has already developed 

 a series of striking and complex glandular hairs of the nature of tubercular 

 emergences. Each is a knob-like expansion of the fruit wall into which 

 a copious prolongation of subjacent mesocarp tissue has spread but 

 further, from an abundant and densely anastomosing complex of vascular 

 bundles that ramify through the outer half of the maturing mesocarp, 

 fine vascular diverticula composed of 2 or 3 spiral tracheae along with 

 delicate elongated sieve-like elements pass through the stalk of the 

 emergences and end in a slight swelling in its middle. The epidermis 

 at this time is comparatively shallow and thin walled, while from the 

 junction of the epidermis with the base of each emergence, elongated 

 unicellular hairs spring, which form a basket like system, round and upon 

 which copious wax exudations subsequently become aggregated. 



At this time the mesophyll is divisible into two recognizable zones, 

 viz.: an outer irregular and large celled region consisting of about 12-13 



