Development and Vascular Organization of the Foliar Organs of Carya cordiformis

Abstract

The apical initials in the stem are associated in the form of an inverted cone. From the uppermost initials the dermatogen is derived; from those lower, the periblem; and from the 6-sided initial at the apex of the cone, the plerome is formed. Development of leaf primordia shows that vascularization begins in the leaf base and proceeds upward into the pinnae as they are formed, and downward into the stem. A 2nd set of procambial traces originating in the leaf base differentiate upwards and unite with the foliar strands; downward they differentiate as cauline traces which unite laterally with procambial traces of other leaves.