HELPFUL SUGGESTIONS 37 



When considering the shape and position of the cap- 

 sule, do not include the operculum. (See "Illustrations 

 of Terms," Plate IV.) The operculum is the hd that 

 covers the mouth of the capsule. It drops off natu- 

 rally when the spores are mature, and sometimes be- 

 fore this takes place, it is loose enough to be easily 

 removed with tweezers or fingers. 



Do not he alarmed at a long list of genus nujnhers. 

 A glance at the illustration of each genus will show 

 whether it is necessary to read the entire description. 

 Always carefully read it if there is any doubt about 

 the illustration being like the moss in question. 



Every point in the Keys and in the descriptions is 

 important. Follow the Keys carefully and study the 

 descriptions thoroughly. A specimen must correspond 

 in every point to its description. Care must be taken 

 to gather normal plants. The beginner at times will 

 not do this. Puzzling variations may be found in 

 mosses as in other plants and also in animals. But one 

 ought not to think that every doubtful case is one of 

 these abnormal growths, for it may be due to some 

 imperfect use of the Keys or descriptions caused by 

 overlooking some detail. When a moss has no definite 

 character and the fruit is lacking, one may be in doubt 

 where to place it even after careful comparison with 

 the illustrations and descriptions. In this case, one 

 must sometimes wait until fruited plants are found, or 

 possibly a compound microscope and technical books 

 are necessary. A troublesome specimen can usually be 



