12 MANUAL OF BOTANY 



as branches only, or branches and leaves, can be recognised on 

 the shoot. Boots almost always bear branches only, leaves 

 occurring on them only under very exceptional circumstances. 

 A further difference between the root and the shoot consists in 

 the fact that the latter always bears the true reproductive organs. 

 The part of the shoot which gives rise to the appendages is 

 termed the stem, and the stem and main root together consti- 

 tute the axis of the plant. 



Plants which show such a differentiation of their prominent 

 form are called Cormophytes. This prominent form is in most 

 cases the sporophyte, and the distinction between the two parts of 



Fig. 15. 



.iitii 



Fig. 15. Protliallns (gametopliyte) of Fern. After Kny. 



its axis can frequently be seen from the very commencement 

 of its development. The cell formed by the fusion of the gametes, 

 usually called the oospore, is first divided by a cell-wall, known 

 as the basal wal', into two segments, of which the upper one, or 

 epibasal ceU, develops the shoot, and the lower, or hypobasal 

 one, ultimately gives rise wholly or partially to the root. The 

 primary root and the primary stem are thus always opposite to 

 each other. 



The thalloid shoot may be regarded as intermediate between 

 a true thallophyte and a cormophyte. 



The relative development of root and shoot may vary very 

 greatly. In most of the lower forms the root is frequently of 



