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GEORGIA. 



This genus was named after George III., but its name was 

 soon after changed to Tetraphis by another botanist. The latter 

 name refers to the four large strong teeth of the peristome, by 

 which character alone the genus is readily recognized. The pel- 

 lucid Georgia (G. pellucida, Figs. 4-7) is very abundant on moist 

 decaying wood, but seems to nourish best on the vertical sides of 

 old stumps. Some of the plants bear peculiar looking tufts of 

 leaves at the summit that might easily be mistaken for the anther- 

 idial heads. The species, however, is monoicous and these heads 

 consist of large numbers of minute bright-green bodies, called 

 gemmae, surrounded by modified leaves. These bodies much 

 magnified are shown in Fig. 7. These fall off and develop into 

 new plants. This method of reproduction is rather rare in mosses 

 and reminds one strongly of the gemmae of Lycopodium or the 

 bulblets of Cystopteris. 



There is another species of this genus and another genus of 

 this family which are found in North America, but they are so rare 

 that none of our readers are likely to meet with them. 



While Georgia belongs to a different family from the hair- 

 caps, there are certain resemblances that have led botanists to put 

 them into one group, the Xematodonteae or thread-toothed mosses 

 in contrast to the Arthrodonteae or jointed-toothed mosses. The 

 jointed-toothed mosses have the teeth of the peristome crossed by 

 very conspicuous bars or joints which are formed by the thicken- 

 ing of the cell walls of a single layer of cells. The mosses we 

 have thus far taken up belong to the thread-toothed mosses, in 

 which the teeth are not jointed and are derived from several con- 

 centric layers of cells. In Georgia the teeth are formed from the 

 division of the whole cellular tissue of the interior of the lid, but in 

 the Polytrichaceee the teeth are formed from more clearly differ- 

 entiated tissue. Each tooth consists of several layers of fine 

 threads (hence the name, thread- toothed), held together by cellu- 

 lar material. In Dawsonia the threads are set free and form 

 brush-like tufts of cilia. These structures are so fundamentally 

 different from those in the jointed-toothed mosses that Arthro- 

 donteae and Xematodontse ought to stand as the great divisions 

 instead of Acrocarpous and Pleurocarpous. 



The Buxbaumias and their allies, the oddest and most curious 

 of all our mosses, belongs with the thread-toothed mosses, accord- 

 ing to most recent writers, but they are not very common and w 



