cataphyll

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun botany A leaf, sometimes abortive, sometimes persistent, that does not develop into a photosynthetic structure, but instead fulfills protective or storage functions. Examples include cotyledons, bud-scales, glochids, rhizome-scales, and bulb-scales.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a reduced or scarcely developed leaf at the start of a plant's life (i.e., cotyledons) or in the early stages of leaf development