OF THE EASTERN UNITED STATES 375 



Comparative Morphology of the Leaves 



Gross Structure 

 Myrtca cerifera, L. 

 The leaves of this plant are simple, alternate, exstipulate, inserted in 

 a 2/5 spiral, pinnate-reticulate in venation, fragrant with a balsamic 

 resinous odor, coriaceous, evergreen and appearing toward the ends of 

 the branches which bear the flower buds of the following season about 

 the middle of May and persisting until the flower buds begin to open, 

 when they gradually fall, as the new leaf buds expand without assuming 

 a copper-red color. They are lanceolate-cuneate or oblong lanceolate, 

 (Plate 83, Fig. 6) varying from 30-100 mm. in length and 5-15 mm. in 

 width, often draw^n out toward both extremities, acute, mucronate, or 

 less often obtuse, or sharply notched at the apex, long cuneiform at the 

 base and decurrent on the short stout petiole. Their margin is thickened, 

 incurved beneath, very slightly eroded, entire or showing one to several 

 teeth in the anterior half or third. The upper surface of the lamina is 

 of a shining dark-green color and exhibits numerous crowded pits, some 

 of which contain orange-red and others golden-yellow glandular hairs. 

 Simple hairs are also present on the depressed midrib and along the mar- 

 gin in the young condition of the leaves, but disappear as the leaves be- 

 come older These are fewer than on M. Carolinensis or M. Macfarlanei, 

 leaves. The lower surface of the lamina is of a yellowish-green color 

 showing fewer simple hairs than M. Carolinensis in the young condition 

 of the leaves. The simple hairs are entirely absent or very rare on this 

 surface of older ones. Orange-red and golden-yellow glandular hairs 

 are very numerous as on upper epidermis. Both midrib and lateral 

 veins, as well as many branches of the lateral veins are very prominent, 

 the lateral veins being inserted on the midrib at an angle of 45-60°. 



Myrica Carolinensis, Miller 

 Leaves simple, alternate, exstipulate, inserted in a 2/5 spiral, pinnate- 

 reticulate in venation, fragrant, membranous, deciduous, beginning 

 to appear toward the ends of the branches which bear the flower buds 

 of the following season the latter part of April (the writer has observed 

 many leaves expanded at Clementon, N. J. on April 23, 1915) and in 

 full foliage by the first or second week in May. They remain green all 

 summer, assume a greenish-brown hue on an extensive scale in October 

 and November and usually have completely fallen by the middle of 



