Najas L.

1. Najas L. 1

Monoecious or dioecious. Leaves conspicuously or minutely dentate at the margins; sheath with or without auricles. Flowers solitary or few together, ebracteate or with a spathe-like bract, pedunculate or subsessile. Style 2- to 4-branched.

1 Dioecious; leaves 1-6 mm wide including the teeth, conspicuously spinose-dentate; stems spinose-dentate or smooth 1. marina

1 Monoecious; leaves less than 1 mm wide including the teeth, minutely spinose-dentate; stems smooth

2 Leaf-sheaths with long, narrow or conspicuous, rounded to truncate auricles

3 Auricleslong,narrowlytriangular;fruit1- 75-2-25mm

6. graminea 3 Auricles conspicuous, rounded to truncate; fruit 2-5- 3 - 5 mm

5. gracillima 2 Leaf-sheaths with short auricles or none

4 Leaf-sheaths with sloping shoulders, not auriculate; leaves with 20-36 minute teeth on each margin 2. flexilis 4 Leaf-sheathswithshort,rounded-truncateauricles;leaves with 5-17 teeth on each margin

5 Areoles of seeds wider than long; leaves up to 3 cm

3. minor 5 Areoles of seeds longer than wide; leaves not more than

1 -2 cm 4. tenuissima