ORDER CCV.—FLUVIALES, OR NAIADES.—THE POND-WEED TRIBE.
Floating plants, of which Aponogeton distachyon is by far the most beautiful. This plant, which is a native of the Cape of Good Hope, has oblong, deeply-ribbed leaves on very long footstalks, and the flowers in two-cleft spikes, with snow-white bracts, which are very ornamental and very fragrant; each flower consists of from six to twelve stamens, and from two to five carpels. The root is tuberous, and eatable when roasted. The Duckweed (Lemna), which is sometimes included in this order, appears to consist entirely of a few leaves floating on the water, each of which sends down a root; and many people believe that it never flowers. If, however, it be watched in the months of June and July, two yellow anthers will be seen peeping out of the side of each leaf; and if the opening be enlarged, the flower will be found to consist of a kind of bag, open on one side, and containing two stamens, with an ovary furnished with a style and simple stigma. The fruit is a one-celled capsule, containing one or more seeds. Some botanists place this plant in a separate order, called Pistiaceæ, from another genus included in it.
ORDER CCVI.—JUNCEÆ.—THE RUSH TRIBE.
The most interesting genus is the Rush (Juncus). These plants, low as they rank in the vegetable world, have a regular perianth of six divisions with six stamens, and a three-celled capsule which opens by three valves. The perianth of the flowers is, however, so small as to be inconspicuous. Most of the species are weeds, which are considered to indicate cold, wet, and poor ground.
ORDER CCVII.—GILLESIEÆ.
A grass-like plant, a native of Chili, with greenish flowers.