Bryophyta. The Bryophytes, or mosses, are for the most part land plants, though a few are aquatic, and with very few exceptions are richly supplied with chlorophyll. They are for the most part small plants, few of them being over a few centimetres in height; but, nevertheless, compared with the plants that we have heretofore studied, quite complex in their structure. The lowest members of the group are flattened, creeping plants, or a few of them floating aquatics, without distinct stem and leaves; but the higher ones have a pretty well-developed central axis or stem, with simple leaves attached. There are two classes I. Liverworts (Hepaticæ), One of the commonest of this class, and to be had at any time, is named Madotheca. It is one of the highest of the class, having distinct stem and leaves. It grows most commonly on the shady side of tree trunks, being most luxuriant near the ground, where the supply of moisture is most constant. It also occurs on stones and rocks in moist places. It closely resembles a true moss in general appearance, and from the scale-like arrangement of its leaves is sometimes called "scale moss." II. Mosses (Musci). The true mosses (Musci) resemble in many respects the higher liverworts, such as Madotheca or Jungermannia, all of them having well-marked stems and leaves. The spore fruit is more highly developed than in the liverworts, but never contains elaters.