MARCHANTIA 



367 



and the capsule, the box at the top. Look for moss plant- oil trees, &l 

 the edges of sidewalks, and on damp soil. With tin- microscope examine 

 archegonia and antheridia. When antheridia from fresh material 

 used, the sperms can usually lit- seen escaping from tin- antheridiom. 



259. Marchantia. — Marchantia is u plant belonging t<> 



I Do 



the moss group, which grows in vciv moist places. It has 

 a thin, broad body or 



> 





* "-.- «3gn 



• 





> «, 





thallus (thal'ltis: Greek, 

 thallos, a young shoot), 

 which is green on the 

 upper surface and brown 

 or gray on the under 

 side. In the middle of 

 the thallus is a midrib. 

 On the upper surface are 

 diamond-shaped mark- 

 ings, each of which lias 

 an opening which leads 

 to an air chamber below. 

 On the under side are 

 rhizoids, which hold the 

 plant loosely to the soil. 

 The marchantias are 

 adapting themselves to a life on land, but they are Btill 

 dependent upon water. Their reproductive habits art- 

 like those of the mosses (Figures 391 and o\^2 ). 



Figure 393. — Marchantia. 



LABORATORY STUDY OF MARCHANTIA 



Examine pieces of the plant and identify tin- thallus. midrib, rhizoids, 

 and markings. Examine the umbrella-shaped, aprighl branches which 

 bear the antheridia or male reproductive organs, the branches with slen- 

 der projections which bear the archegonis or female reprodnctivi ma 



With a microscope examine a cross BOCtiOD <»f the thallus, and ol the 



openings and air chambers. 



