262 The Great Gulf. [Sess. 



with an upright, leafy stem, bearing one or more capsules at 

 the top of the stem ; and, second, one with a prostrate, creep- 

 ing stem, bearing capsules at various points of the stem. 

 Those two types have, however, practically the same life- 

 history, which we will now follow out. 



As we have seen, a moss plant consists of a stem with 

 leaves, bearing capsules usually supported on a stalk or seta 

 of varying length, but sometimes quite sessile. This capsule, 

 like the sporangium of a fern, produces spores which, when 

 the capsule is ripe and the lid falls off, are scattered abroad in 

 dry weather. Falling on a suitable nidus, the spores ger- 

 minate and give rise to a mass of fibrous matter called the 

 protonema, consisting of green cellular fibres. These fibres in 

 turn give rise in varying numbers to young moss plants 

 similar to the parent. Such plants on attaining maturity 

 produce, sometimes on the same plant, sometimes on different 

 plants, (1) antheridia, consisting of club-shaped bodies con- 

 taining mother-cells, each of which produces a spermatozoid. 

 On the rupture of the antheridia and breaking up of the 

 mother-cells the spermatozoids are set free. The moss plant 

 bears (2) archegonia, which are bottle-shaped bodies with a 

 long neck, an ovum being contained in the body of the bottle. 

 This ovum is fertilised by a spermatozoid from the antheridia, 

 and from the fertilised ovum grows the seta, carrying the 

 capsule with spores on the top of it. The sexual process is 

 practically the same as in the ferns. 



Here again we have a wonderful life-history. First, we 

 have the spore which, on germination, produces the protonema. 

 From the protonema grows the moss plant, producing in its 

 turn sexual organs, from the fertilised ovum of which arises 

 the seta, and capsule, producing spores once more. This is 

 a very different state of matters compared with what we found 

 existing among the ferns. Here the oophyte or ovum-bearing 

 generation is the moss plant itself, while the sporophyte or 

 spore-bearing generation is not a separate plant at all, but is 

 parasitic on the oophyte in the form of a seta and capsule. 



In many ways allied, we yet see a great differentiation in 

 the life-history of ferns and mosses, — a great gap, indeed, in 

 the chain of evolution, with how many links awanting who 

 can say ? Where are these links ? Have they been lost in 



