1. Wolffiella gladiata (Hegelm.) Hegelm.

Pl. 98 d–e; Map 395

W. floridana (Donn. Sm.) C.H. Thomps.

Plants of 1–20 fronds connected at bases into an uneven globular mass, not producing turions. Roots absent. Fronds 4–12 mm long, 0.4–0.7 mm wide, flat, linear or ribbonlike, sometimes arc-shaped, green or rarely with reddish spots or areas. Papules absent. Veins absent. Pouches 2 per frond, the one along the margin of the frond producing vegetative buds, the one on the upper surface producing flowers. Fruits 0.3–0.4 mm long, lacking wings, the seed lacking ribs. 2n=40, 42.

Uncommon in Dunklin and Stoddard Counties (eastern U.S. west to Texas; disjunct in Washington and central Mexico). Floating on shallow, stagnant water or submerged near water’s surface in ponds and sloughs.

Undocumented sightings attributed to this species from St. Charles and Wayne Counties indicate that this species may be more widely distributed in eastern Missouri than previously suspected.