MOSS. 

 Atrichum undulatum Beauv. 



PRELIMINARY. 



MOSSES appear so much alike to those who have not 

 given special attention to them, that it is more difficult 

 to definitely point out a particular species than in the 

 other plants of the book. The one selected for study 

 is widely distributed, and very common, forming carpet- 

 like patches in woods, and on shady banks. The single 

 plants stand from two and a half to four centimeters 

 (one to one and a half inches) high. The leaves, which 

 are abundant, are five millimeters (quarter of an inch) 

 or more long, narrow, with wavy sides ; the undu- 

 lations appear, when the leaf is held to the light, as lines 

 passing obliquely from the middle to the margin. 



The male and female plants are usually found in sep- 

 arate patches, as in Marchantia. The male flowers (see 

 fig. 5) are easily recognized by being cup shape, and are 

 distinguished from the rosette of leaves terminating a 

 rapidly growing stem by having a distinct, rather flat 

 bottom to the cup. They are readily found at almost 

 any time during the year, and are especially abundant 

 in early summer. 



The female flowers, which are less common than the 

 male, differ so little in external appearance from the 

 ordinary vegetative condition, that it often requires a 



