quaternary leaf vein fourth order leaf vein (related) PO:0008022 plant_anatomy 四次葉脈 (Japanese, exact) A leaf lamina vein (PO:0020138) arising from a tertiary leaf vein (PO:0008021). veinlet (narrow) vena cuaternaria (Spanish, exact) FNA:e3ab3fff-3015-4b76-af51-fc69ee9396d8 FNA:dba43715-e71f-4192-87a2-489f5b9b4c82 Vein orders only apply to hierarchically branching vein patterns, not to dichotomously branching vein patterns, as found in some ferns and gymnosperms. cross-vein (narrow) PO_GIT:435 leaf lamina vein