Elodea
(from elodes, growing in watery places). Water Thyme. SYN. Udora. ORD. Hydrocharideae. A genus of unattractive slender aquatic perennials. There are eight species, none of which are worth growing. E. canadensis merits mention in this work from the fact that its extremely rapid increase often entails no little work on the gardener. It was introduced from America to County Down about 1836, and into England in 1841. Very soon, it filled a number of canals and rivers with its dense, matted growths to such an extent as seriously to impede navigation. No inconvenience of this kind is complained of in its native country. In many places now (fish ponds, ornamental waters, &c.), where at one time it was so abundant, it seems to have almost disappeared, perhaps owing to the exhaustion in the soil of the specific nutriment on which the plant feeds.