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be of equal or even of greater importance. The leaf has no 

 stomata or breathing pores and consists generally of only one layer 

 of cells, which are not all of the same size and shape, for those at the 

 base are often much larger than those at the apex. Not only is 

 the size of the cells noteworthy but also their shape, as this is found 

 to be highly characteristic in whole families of Mosses. In many 

 cases, the leaf is furnished with a vein, which is sometimes narrow 

 and sometimes broad — in some cases it ends as a point to the leaf, 

 while, in others, it is much prolonged into an excurrent point or 

 hair, as in Tortula. In a rare case or two, it leaves the leaf much 

 below the tip and so resembles the dorsal awn, so common in grasses 

 Those bodies called stipules which are so noticeable in many 

 families of flowering plants, do not occur in mosses, but they are 

 found in many of the Hepaticoe. Chlorophyll, the green colouring 

 matter of plants generally, is more or less abundant in mosses, in 

 the protonema as well as in the leaves, the terms "highly 

 chlorophyllose " and " sparingly chlorophyllose " being much used 

 in descriptions. It is now time for us to look at one of these 

 specimens (let us take the Polytrichum commune or common 

 hair-moss) and ask what is that little vessel on the top of the stalk 

 and what is the stalk itself ? The vessel has been already spoken 

 of as the capsule and the stalk is the seta, which lengthens with 

 the development of the capsule or, strictly speaking, the 

 sporogonium. The capsule and its contents are, collectively, the 

 fruit. In our passage to a fuller description of this fruit, we must 

 stop and see what provision is made for the reproduction of mosses. 

 We find no stamens and pistils, but we have male and female flowers 

 by the co-operation of which reptoduction is effected through the 

 spore generation as already explained. Among flowering plants, 

 the stamens and pistils are commonly enclosed in the same floral 

 envelope but, in many cases, they are in different flowers on the 

 same plant, and in other cases, on different plants. You will prob- 

 ably remember the terms hermaphrodite, monoecious, and dioecious, 

 Mosses are hermaphrodite, monoicous, dioicous, or polyoicous, that 

 is to say, the antheridia and pistillidia may befl) on the same plant, 

 or (2) on different plants, or (3) on the same as well as on different 

 plants. Inmonoicousmosses, the different organs may be in the same 

 inflorescence or in separate inflorescences on the same i)lants. The 

 Antheridium (anther-like) is a sac, shaped very much like a club. 

 It consists of a single coat and encloses a great number of tiny cells, 

 which are filled with a kind of mucilage. Each cell contains an 

 antheruzoid. The Antheridium opens at the top to discharge its 

 contents. The antherozoid is a slender threadlike body, which, 

 being furnished at its thin end with two cilia, is able to move freely 

 about. The Pistillidium is shaped very much like a Florence oil 



