Elodea Michx

5. Elodea Michx View in CoL 1

Dioecious or with hermaphrodite flowers; stems elongated. Leaves submerged, verticillate or sometimes opposite, sessile, usually linear, with 2 minute, entire nodal scales. Flowers pollinated at the water-surface. Spathes tubular, axillary, sessile, 1-flowered. Petals subequalling the sepals. Stamens usually 9. Ovary sessile within the spathe, attenuated into a long, filiform beak; styles 3, usually 2-lobed, free. Literature: H. St John, Darwiniana 12: 639-652 (1963

Rhodora 67: 1-35, 155-180 (1965).); 1 Sepals of female flowers 1-1-8 mm; male flowers breaking free and rising to the water-surface; leaves less than 2 mm wide

3. nuttallii

1 Sepals of female flowers 2-3-5 mm; male flowers not breaking free; leaves usually at least 2 mm wide

2 Leaves usually c. 10x2 mm, oblong-linear, rounded at the apex; sepals of female flowers 2-2-7 mm 1. canadensis

2 Leaves up to 25 x 2-5 mm, gradually tapered to the acute apex; sepals of female flowers 3-3-5 mm 2. emstiae