7 6 



A TEXT-BOOK OF BOTANY. 



The following table shows the main divisions and subdivisions 

 of the Archegoniates : 



Bryophytes. . . . I He P atic (Liverworts). 

 JMusci (Mosses). 



Archegoniates 



Pteridophytes . . , 



Filicales (Ferns). 

 Equisetales (Horsetails). 

 Lycopodiales (Club Mosses), 



BRYOPHYTES 



The structure of the sexual organs in the Liverworts (Fig. 44) 

 and Mosses (Fig. 49) is essentially the same, but the vegetative 

 organs are more or less dissimilar. In the Liverworts the plant 



FIG. 44. A common moss (Funaria). A, germinating spores: v, vacuole; w, root- 

 hair; s, exospore. B, protonema about three weeks after germination: h, procumbent 

 primary shoot; b, ascending branch of limited growth; K, bud or rudiment of a leaf -bearing 

 axis with root-hair (w). After Sachs. 



body or thallus lies more or less close to the substratum or rises 

 somewhat obliquely, whereas in the Mosses the part we designate 

 as the plant is in all cases an upright leafy branch. The moss 

 plant is said to have a radial structure from the fact that the 

 leaves radiate from a central axis, while in the Liverworts the 

 thallus is dorsiventral ; that is, as a result of its habits of growth, 

 it is characterized by having a distinct upper and lower surface. 



