leaf trace

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A strand of vascular tissue that extends between the vascular bundle of a stem and a leaf.

from The Century Dictionary.

• noun A foliar trace. See trace.

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

• noun botany An extension of vascular tissue from a plant's stem into a nearby leaf, resulting in a leaf gap in the plant's stele.