62 



COMPOUND ORGANS OF PLANTS. 



their surface in the form of dark nuclei or spots ; and on the 

 left-hand margin we have a foliaceous lichen, Parmelia con- 

 Fig. 27. 



spersa, with its fructification in shields or cups, the cortical 

 matter of the thallus forming a rim or border round the 

 nucleus ; 3 is a piece of the thallus of Parmelia oonspersa 

 with a section through the apothecium; 4 is a magnified 

 section of an apotheoium, showing the young asci or sacs 

 which contain the spores imbedded in the substance of the 

 apothecium; 5 is a representation of two of these asci or 

 sacs, with their contained spores and accompanying fila- 

 ments highly magnified ; 6 shows the podetium or stalk- 



