Sentence:  In one forked leaf there is a distinct vein <WSD>dichotomy</WSD>, and the leaf boundary commences 1.5 mm above the <WSD>dichotomy</WSD>. 
Meaning of the word marked with <WSD> tags:  Division and subdivision; bifurcation, as of a stem of a plant or a vein of the body into two parts as it proceeds from its origin; often successive.