CHAPTER IV. 

 MOSSES (MUSCI) 



Habitat. Mosses, which are a higher form of plant life 

 than the hepatics, are found growing in streams, moist soil, 

 on tree trunks and on rocks. 



Morphology of the Gametophyte or Sexual Plant. The 

 gametophyte or permanent plant of the mosses, resembles 

 externally the higher plants. The plant consists of a stem or 

 central axis from which grow three sets or rows of leaves. 

 From the underground part develop numerous brown 

 rhizoids, which hold the plant in position and absorb nourish- 

 ment from the soil. 



Reproduction The two forms of reproduction common 

 to the mosses are (1) sexual reproduction and (2) asexual 

 reproduction. 



1. Sexual Reproduction. The two types of sex organs are: 

 (a) Antheridia and (6) Archegonia. 



(a) Antheridia grow at the tip of the male plant and in 

 the axils of the leaves, arranged in a cluster or rosette. An 

 antheridium is club-shaped. It has an outer wall composed 

 of a single layer of cells. The wall encloses a mass of cells 

 which change to sperms or male reproductive cells. When 

 the sperms are mature the wall breaks and the sperms swim 

 out. A sperm is a coiled elongated cell with two cilia. 



(b) Archegonia grow from the tip of the female plant and 

 are surrounded by a rosette of leaves. An archegonium 

 consists of a neck, or narrow portion, a venter or enlarged 

 portion containing the egg or female cell, and a pedicle or 



