I have Dr. Grout’s permission to reproduce two illustrations, which represent fairly that phase of his valuable book. Figure 9 shows Ceratodon purpureus L, and the text pertaining to the same is as follows: “Ceratodon is one of the commonest of all our mosses. It is found on the edges of paths, roofs of old buildings, sand by the seashore, and in general any barren compact soil is its favorite habitat. The plants are short and grow close together, forming dense thin mats of dark green. The lance-like young sporophytes appear early in spring as soon as the snow is melted. By the middle of summer the capsules often decay beyond recognition, and the seta breaks from the plant at the touch. Unless one has become very familiar with Ceratodon it is not always easy to recognize it without mature capsules. When the capsules have fully matured they shrink when dry and become furrowed. This peculiar furrowing, the dark rich color of the capsules, a color called purple by the older botanists, but which is really a very dark chestnut or red-brown, make it easy to recognize this species.” Plate II. shows the Hair-cap Mosses, Polytrichum, the largest of all our species. There are four common species all having square capsules which character distinguishes them from Pogonatums, the latter having cylindric capsules. “The Ohio Hair-cap without the sporophyte (seta and capsule, commonly called fruit) is not readily distinguished from the Common, as the leaves and general appearance are very similar. But with the sporophyte present, the distinctions are clear. In Figs. b and d (Plate II.) note that the capsule of the Common Hair-cap is almost cubical, that the lid has a _very short beak_, and that the capsule is entirely covered by the calyptra. The capsule of the Ohio Hair-cap (e) is elongated, slender with a tapering neck, and with a much longer beak to the lid. The lid and the calyptra of the Ohio Hair-cap fall early in June, very soon after the spores are ripe, and it is not always easy to find either in position, but if the calyptra be found, it will be seen to cover the upper portion of the capsule only. The Common Hair-cap, although occurring in woods, is most common in open fields; the Ohio Hair-cap being most frequent in shady, more moist spots, often in deep woods. The remaining two species are easily distinguished from the two mentioned above by the margins of the leaves, which are thin and membranaceous, and are folded in over the central portion of the leaf, as illustrated in o, o′ and p.” [Illustration: Plate II., Polytrichum or Hair-cap Moss. Figs. a (dry), b (moist), c (leaf), d (capsule) and f are P. commune; Fig. e, capsule of P. ohioense; Figs. g, h and p, P. piliferum; Figs. o and o′, P. juniperinum.]