75 



tlie archegoniuin, tiiis is called the Basal 

 Wall. This separates the shoot-forming from 

 the root-forming portion of the embryo. 



2. A wall is next formed at right angles to the 

 first which is known as the Transversal Wall. 



3. A Median Wall is developed. 



The embryo now consists of eight cells called 

 octants. 



4. Each octant forms a wall parallel to the basal 

 one. The cell thus produced becomes the 

 growing apex of each octant. 



The four cells nearest the growing point of the 

 prothallium are known as the Epibasal half of the 

 embryo, and the four cells farthest from the growing 

 point are known as the Hypobasal half. 



I. EPIBASAL HALF. Upper octant forras the stem — 

 sister octant a few hairs. Lower octant with help 

 of sister octant forms the first leaf. 



II. HYPOBASAL HALF. Upper octaut with its sister 

 octant forms the foot. Lower octant forms the 

 root — sister octant a few root hairs. 



The Foot swells and absorbs nourishment from the 

 prothallium. 



2 he Root makes its way into the ground, growing 

 away from the apex of the prothallium. 



Tlie Z^a/ (Cotyledon) curls round the stem apex. 

 The Stem makes its appearance last. 



