SECTION 3.] 



SEEDLINGS. 



19 



28. This hypogccous germination is exemplified on a larger seale by the 

 Oak (Fig. 30, 87) and Horse-ehestuut (Pig. 38, 39); but iu these the 

 downward gjrowth is wholly a stout tap-root. It is not the caulicle ; for 



this lengthens liardly any. Indeed, the earliest growth which carries 

 the very short caulicle out of the shell comes from the formation of foot- 

 stalks to the cotyledons ; above these develops the strong plumule, below 

 grows the stout root. The growth is at first entirely, for a long time 



FiQ. 31. A Beech-nut, cut across. 32. Beginning germination of the Beech, 

 showing the plumule growing before the cotyledons have opened or the root has 

 scarcely formed. 33. The same, a little later, with the plumtile-leaves developing, 

 and elevated on a long internode. 



Fig. 34. Emhryo of Pea, i. e. a pea with the coats removed; the short and 

 thick caulicle presented to view. 35. Same in advanced germination : the plumule 

 fias developed four or five internodes, bearing single leaves ; but the first and sec- 

 ond leaves are mere scales, the third begins to serve as foliage ; the next more so. 



