decurrent

adjective

(L. decurrere: to run down) Extending downwards beyond the point of insertion, e.g. of a lamina extending downwards to form a flange along the petiole; applied usually to leaves in which the blade is apparently prolonged downward as two wings along the petiole or along the stem; with basal leaf margins extending down the stem past the leaf insertion as ridges or narrow wings; e.g., Coleochaetium, Morinia, Scapania, Plagiothecium.