The Lesser Alpine Club Moss is probably more common than is generally supposed, especially in the North of England. It grows in damp situations and is often very much mixed up with other herbage, so that it is easily overlooked. It is now necessary to describe the two or three curious little plants which are closely related to the Ferns and Club Mosses. _Isoëtes lacustris._ In this case the generic name originates in two Greek words—_isos_, “equal,” and _etos_, “a year.” This has reference to the fact that the plant keeps its leaves all through the year and does not alter in appearance. The specific name _lacustris_ is derived from the Latin word _lacus_, a lake, and is an allusion to the fact that the plant grows in such a situation. The Quillwort. This is an interesting little plant which is entirely aquatic in its habits. The Quillwort has a tuberous root-stock, and from this arise a large number of dark green leaves, somewhat resembling quills in shape. These are about three or four inches in length, and when the plant is growing in quantity in some pool, it is often taken for a kind of grass. At the base of the leaves, partly protected by the sheathing, are to be found the spore capsules. These cases are of two kinds, those on the outermost rows of leaves containing the large spores, and those on the inner leaves being responsible for the small spores. [Illustration: Isoëtes lacustris. The Quillwort.] The Quillwort is often abundant in mountain lakes in Scotland and the North of England. Owing to its habit of growth, however, the plant is usually unnoticed by the majority of people. Another species of Quillwort—_Isoëtes Hystrix_—occurs in the Channel Islands, but it has not been found elsewhere in the United Kingdom. _Pilularia globulifera._ In this case the generic name is formed from the Latin word _pilula_, “a little pill,” this being a reference to the curious pill-like spore capsules which the plant produces. The specific name of _globulifera_ is made up from two Latin words—_globus_, “a ball,” and _fero_, “I carry.” This is another allusion to the rounded sporangia. The Pillwort.