i6o 



MORPHOLOGY. 



the egg is borne, which is a surer way of determining the limits 

 of the two phases of the plant. 



337. The male and female moss plants. — The two plants of mnium shown in 

 figs. 198, 199 are quite different, as one can easily see, and yet they belong 

 to the same species. One is a female plant, while the other is a male plant. 



The sexual organs then in mnium, as 

 in many others of the mosses, are borne 

 on separate plants. The archegonia 

 \^W ,^i) ^^'^ borne at the end of the stem, and are 



protected by somewhat narrower leaves 

 which closely overlap and are wrapped 

 together. They are similar to the 

 archegonia of the liverworts. 



Female plant (gametopbyte) of a moss 

 (mnium), showing rhizoids below, and the 

 tuft of leaves above which protect the arche- 

 gonia. 



Fig. 199. 

 Male plant (gametophyte) of a rposs 

 (mnium) showing rhizoids below and the 

 antheridia at the center above surrounded by 

 the rosette of leaves. 



The male plants of mnium are easily selected, since the leaves at the end 

 of the stem form a broad rosette with the antheridia, and some sterile threads 

 packed closely together in the center. The ends of the mass of antheridia 

 can be seen with the naked e}'e, as shown in fig. 199. When the antheridia 



