nervule

noun

1. A minor, nonsupporting vein in a leaf of a plant; a branch vein of a nervure (supporting vein) or of another nervule.

   “D. reticulata (Blum l.c.) leaves 3-nerved, besides the 2 marginal nervules, ovate-oblong, acuminated, rounded at the base, or somewhat cordate, reticulated beneath and covered with ochraceous dots; panicles terminal; calyx almost quite entire; anthers fixed by the back, furnished with somewhat rhomboid, inappendiculate connectives.”

2. A minor vein in a wing of an insect.

   “A close examination of the wing will always show a partially atrophied disco-cellular, connecting these nervules of the discoidal with either the subcostal or the median nervures, even when one of them has been described as quite free.”

   “The origin of the first and second median nervules corresponds to that of the two superior subcostal nervules; and the nervule closing the cell unites with the apical portion of the median nervule at a right angle.”

   “2003, W. J. Holland, Cassia B. Farkas (editor), Field Guide to Butterflies, Revised and Updated Edition, page 12, The branches of these compound veins are known as nervules. The median vein always has three nervules. The nervules of the subcostal veins branch up and outward, with from four to five subcostal nervules, toward the costal margin and the apex of the forewing.”