CHAPTER XXVI.

MOSSES AND THEIR RELATIVES

=Mosses form another big family=, the members of which are generally =easy to recognise=, even when you know little about them, because they all have a very strong family likeness. If you look for mosses in a shady wood, or on stones and tree stumps near a waterfall, you will often find large numbers of them growing together, sometimes forming sheets of soft green, covering the stones and earth and tree stumps. These luxuriant mosses grow, as a rule, in moist and shady places, but there are others which grow on dry walls or between the cobbles of little-used paths, and generally form brilliant green patches of tiny plants, like masses of velvet. If you pick out a separate plant from among these and look at it through a magnifying-glass, you will see that it is very like the bigger ones of the wood.

For our study it is perhaps better to choose one of the bigger ones, because all its parts show so clearly.

1. If you take a single plant, you will find that it appears to be marked out into root, stem, and leaves, though all these parts are small and simple.

2. The stem is delicate, and you will not be able to see any “water-pipe” cells when you examine it with your magnifying-glass.

3. The leaves are always very simple and small, generally narrow, pointed, and clustered thickly round the stem with no special leaf stalks.

4. At the ends of the stems, you will often find little structures, sometimes rather pink in colour, which look something like flowers (~see~ fig. 130), but they are really ~quite different in their nature from true flowers~.

5 and 6. ~There are no seeds~ and no seedlings.

7. At the top of some of those plants which seem to have flowers you will find later that a long slender stalk grows out with a little capsule or box at the end of it (~see~ fig. 131 (~b~)). This single box or capsule really corresponds to the numbers of small spore-cases on the backs of fern-leaves, for it ~is in this capsule that we find the spores~, which are simple and ~single-celled~ like those of the fern.

8. When ~these spores~ grow, however, they do not form a prothallium as they do in the ferns, but they ~grow out into the leafy moss-plant~.

It is very difficult really to see how this can be the case, unless you study mosses very carefully with a microscope, but all the same it is true that ~the leafy moss-plant corresponds to the prothallium of the fern~.

9. On the leafy moss-plant you find the simple stalk and capsule which gives rise to the spores; this ~spore forming part of the plant always remains attached to the leafy plant~, so that we find the two portions of the plant in contact all their lives, and not separated as they are in the fern.

The only other plants which are built on anything like this plan are the liverworts, though you might hardly believe it, because most of them are not marked out into leaf and stem at all, but are only flat, creeping, green structures, which do not look in the least like the mosses. It is true that they are not very near relatives, but because they have spore-cases rather like those of the mosses in some very important ways, the scientists have put them together in the big moss family. The true mosses have a special smaller family to themselves within this, a family which is quite easy for you to recognise when you go out on your rambles into the woods.