Purple nutsedge(Cyperus rotundus L.)develops as a series of shoots connected by bulbs, rhizomes, and tubers. The leaves contain parallel, collateral vascular bundles with the majority of the photosynthetic cells concentrated in the sheathing girdle around each bundle. The upper leaf surface consists of a single layer of large epidermal cells covered by a thick cuticle. Stomates occur only in the lower surface. The vascular bundles vary from collateral to amphivasal as they pass from the leaves through the bulb into the rhizomes and tubers. Newly developing rhizomes and tubers appear white and fleshy with a parenchymatous epidermis and cortex. Mature rhizomes appear brown and wiry with a deteriorated outer cortex and a lignified inner cortext and endodermis. Tubers and bulbs form similarly at the rhizome apices with each accumulating starch. The interconnecting vascular system appears to remain intact throughout the growing season.