22 BRITISH MOSSES. 



the number of teeth of which it is composed is exact order. Each genus has its 

 own, and it always is one which can be divided by four; four, eight, sixteen, 

 thirty-two, sixty-four ; the intermediate numbers are never found. The teeth are 

 sometimes double, sometimes forked, often beautifully marked and furrowed, and 

 at other times connected by little transverse bars. The Tortula, or screw-mosses, 

 derive their name from the fact of their peristome being twisted like the top of a 

 shell ; the Dicranum, or fork mosses, from their teeth being forked ; the Zygodon, or 

 yoke-mosses, are so called because the teeth are yoke-shaped ; and the Didymoclon, 

 or twin-toothed mosses, have their teeth in pairs. The peristome is often yellow or 

 brilliant red ; its office is to protect the seed from too much damp, which, before it 

 is fully ripe, would injure it ; and it is therefore extremely sensitive to moisture, 

 opening in dry weather and closing in wet. Some of the Hypnums, or feather- 

 mosses, have very large capsules, and if they are gathered before the seed is quite 

 matured the lid will easily come off, and the bright outer fringe of yellow teeth 

 will immediately spread out like rays, but as quickly close again on feeling even 

 the slight moisture of the breath. And this may be observed with the naked 

 eye. 



Hitherto we have spoken of the outside of the seed-vessel. The interior contains 

 the column {columella), to which are attached the bags (spore-cases) containing - 

 the seed (spores) . In the hair-mosses the top of the column spreads out like a 

 table, and the points of the fringe are united to it. (See Illustration of the 

 different parts of fructification) . 



Collectors will at first be puzzled when they discover that some mosses are 

 never found in fruit. The reason of this is that all the mosses of one species in a 

 particular locality may have flowers of one kind only, when the male and female 

 are situated upon different plants ; and therefore the fructification can never come 

 to maturity. The moss may even be wholly barren. The Orthotriclmm phyllan- 

 tlmm, or frizzled bristle-moss, is found in nearly all parts of the world ; more than 

 fifteen thousand feet above the sea-level, " on the highest point of vegetation on 

 Chimborazo," also at Cape Horn, and in England, and it has never been seen in 

 fruit, but is propagated by buds (gemmce) , formed at the ends of the leaves. Of these 

 things the reasons are hidden from us, just as is the manner in which the different 

 parts of the moss flowers act upon one another at all, so as to produce any seed. 

 We can but say, " It has pleased God that it should be so ;" though we may 



