Hydrocharitaceae . . . . Waterweeds

Other spp./genera include: Hydrocharis morsus-ranae (Frogbit) with nearly round cordate floating lvs, Stratiotes aloides (Water-soldier) with linear vertical lvs, Hydrilla verticillata (Esthwaite Waterweed - rare in Cumbria but similar to E. nuttallii), Vallisneria spiralis (Tapegrass) and Najas spp. (Naiads) with toothed lvs but local.

Egeria . . . Large-flowered Waterweed

Egeria densa . . . Large-flowered Waterweed

Uncommon escape in UK

Elodea . . . Pondweed

Elodea nutallii . . . Nuttall's Pondweed

Leaves twisted and recurved

Elodea canadensis . . . Canadian Pondweed

Leaves not twised or recurved; Common as an escape from ponds and aquaria

Lagarosiphon . . . Curly Waterweed

Lagarosiphon major . . . Curly Waterweed

Leaves more strongly twisted and fully recurved than Elodea and spiral lower leaves; an increasing problem as an invasive escaped from fish-tanks