Zosterella spp (Jacq.) MacM.: Water stargrass Pontederiaceae (pickerelweed family). Native perennial. Submersed rooted plant found in quiet water, streams, shallow water and mudbanks. Roots are long and slender, and are formed at the nodes of the slender branching stems. Grass-like, linear, stalkless leaves are 4 - 6 in (10 - 15 cm) long and arise alternately on the stem. Leaves do not have a prominent midvein. The base of the leaf enlarges to clasp or almost surround the stem like an open tube; this structure has two upward-pointing tips. A single star-shaped yellow flower, made up of 6 strap-like petals, arises from the end of a long slender stalk and is held at the surface. This plant produces dense stands and can be a weed problem.