20 PRACTICAL BOTANY. 



5. In some cases the branches of the thallus may 

 have assumed peculiar forms, together with an erect 

 position : these are the branches which bear the 

 sexual organs, and two different types may be easily 

 recognised as borne upon different individual plants, 

 viz. 



a. Branches with a relatively thin stalk, bearing a 

 terminal disk with crenate margin, and having 

 numerous dot-like markings on the upper surface : 

 these are the male branches, having the antheridia 

 on their upper surface. 



b. Branches, also with thin stalks, bearing a terminal 

 star about J inch to inch in diameter : these are the 

 female branches, which produce the archegonia on 

 their under surface, and ultimately the sporogonia and 

 spores. 



II. Remove a thallus carefully from the soil, and 

 wash with water, taking care not to injure it, and 

 examine the organs on its lower surface with a pocket 

 lens : note especially 



1. The numerous rhizoids or root-hairs, attached 

 chiefly to the central midrib. 



2. The amphigastria, white or purple lamellae 

 attached to the lower surface of the thallus, and most 

 clearly seen in the regions near the apex, where they 

 are closely aggregated so as to protect the young tissue. 

 These may be compared with the " leaves " of the 

 Mosses (cf. note, page 1). 



There will frequently be found growing in positions suitable 

 for Marchantia, and often associated with it, another Liverwort 

 called Lunularia, which is similar in general contour, but is 

 usually of a lighter green colour : it may readily be distinguished 



