TRUE MOSSES (BRYALES) 



419 



Most parts of the Moss absorb water and salts directly. Even 

 the leaves are probably able to absorb. The leaves carry on 

 active photosynthesis and supply the carbohydrates. No vascu- 

 lar bundles occur, but in many Mosses there are strands of elon- 

 gated cells which assist in conducting and distributing the foods. 

 The erect habit and the radiate arrangement of the leaves on the 

 stem enable the plant to make the best use of light. 



Knowing that the leafy green plant is the gametophyte, one 

 knows where to look for the sex organs. They are produced on 



Fig. 374. — The sex organ.s of Moss. A, highly magnified vertical sec- 

 tion through the apical region of the stem of a gametophyte, showing arche- 

 gonia (a) with eggs at (c). B, a similar section through a plant bearing 

 antheridia (t). Sperms escaping from an antheridium and one sperm much 

 enlarged are shown at s. 



the upper end of the stem and are quite well surrounded and hid- 

 den by the upper leaves. If one carefully pulls off the terminal 

 leaves from plants that are in the reproductive condition, the 

 sex organs may be found. They stand erect on the stem tip and 

 are so large that they can be seen with a magnifier of very low 

 power. The antheridia can sometimes be seen without any 

 magnifier. The archegonia are flask-shaped and have very long 

 necks, while the antheridia are club-shaped {Fig. 374)- In many 

 Mosses both sex organs occur on the same plant, but in the one 

 shown in the Figure they occur on separate plants. The male 



