This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Eel-grass Family. Perennial marine plants with creeping rootstocks and flattened, branching stems. Leaves all alternate, 2-ranked, linear, flat or complicate, acute or obtuse at the apex and sheathing at the base. Flowers monoecious or dioecious, arranged on a one-sided spadix and enclosed in a close fitting ultimately rupturing spathe. Perianth none, but some of the flowers covered by a hyaline envelope. Staminate flower of a single, sessile, 1-celled anther. Pistillate flower of two, united carpels, with a short or elongated style and 2 thread-like stigmas. Seeds ribbed or smooth.
Represented in North America by two genera, one Pacific and the following: