280 LETTER XXIV. 



Britannica of Drs. Hooker and Taylor, a valuable 

 book, in which are accurate fijjures of nearly all the 

 species found in this country. To it I refer you, if 

 you wish to prosecute this branch of Botany. 



Of about the same rank in the scale of organization 

 are the plants called Jungermannias, which look very 

 much like Mosses (Plate XXIV. 2. jig. 1.), and 

 which like them have little roundish bodies called 

 anthers {fig. 4. & 5.) and a theca {fig. 2. c.) elevated 

 on a stalk. They are distinguishable ; firstly, by their 

 theca bursting into valves, and secondly, by their 

 spores being mixed with tubes, formed of curiously 

 twisted threads {fig. 9.)> ^^^ called elaters. They 

 grow in tufts and patches, in damp and shady places 

 all over Great Britain, occupying the bark of trees, 

 and the surface of rocks and stones, or creeping among 

 the herbage on the banks of rivers, on heaths, marshes, 

 and in shady woods, and even inhabiting gloomy 

 caverns where scarcely any other vegetable can exist. 

 A noble illustration of these tiny plants was pubished 

 some years ago by Professor Hooker ; it forms the 

 most complete local monograph of any genus ever pub- 

 lished, and is indispensable to all those who would 

 occupy themselves with an inquiry into the habits 

 and differences of the tribe. 



