ORDER CCXIV.—EQUISETACEÆ.—THE HORSE-TAIL TRIBE.
The thecæ of these well-known plants are contained in terminal cone-like spikes or catkins, from four to eight lying in each scale. The stems are tubular, and articulated with whorls of membranaceous sheaths, and of slender branches, jointed, and sheathed like the stem at every joint. All the species of Equisetum abound in silicious matter, and particularly the Dutch Rush (E. hyemale), which is used for polishing both wood and metal. The handsomest species is E. sylvaticum.
ORDER CCXV.—CHARACEÆ.
Aquatic herbs, contained in the genera Nitella and Chara, always growing under water, with slender jointed stems, surrounded at the joints by whorls of tubular leaves or branches, which are either membranaceous and transparent, as in Nitella; or brittle, and more or less encrusted with carbonate of lime, as in Chara, Stonewort. The organs of reproduction are formed in the axils of the branches, and consist of transparent globules, and hard, spiral nuculas, which appear to be formed of twisted leaves, the points of which often form a kind of crest. Young plants are only produced by the nuculas.
ORDER CCXVI.—MUSCI.—THE MOSS TRIBE.
