EXPLANATION OF THE PLATES. 



Fig. 2. Longitudinal section of fig. I.: a. section of one of the lobes 

 of the embryon bud; b. base of the petiole; c. a part of 

 the stem; d. spiral vessels entering the petiole; /. liber; 

 g.g. pith; i. alburnum, (p. 385). 



3. Transverse section of fig. 1 : a. the embryon bud ; c. liber ; 



d. alburnum ; e. pith. (p. 386). 



4. None. 



5. Wedge cut from the trunk of a lilac tree twenty years old : 



. a bud not yet completely developed; b. one fully de- 

 veloped : both originated in the first year's growth of the 

 part. (p. 392). 



6. Longitudinal section of a bud of Syringa vulgaris, cut in 



autumn : a. rudiment of the pith of the embryon branch ; b. 

 alburnum of the embryon branch ; c. c. c. scales of the bud ; 

 d. the germ; e. cicatrix of the fallen leaf; /. rudiments of 

 spiral vessels ; g. the cortex ; h. the alburnum ; i. the me- 

 dullary sheath ; and k. the medulla of the twig bearing the 

 bud. (p. 387). 



7. A. Transverse section of a branch of Philadelphus corona- 



rius, eight years old : a.b.c. buds just developed, but the 

 origin of which may be traced to the first year's growth of 

 the branch (p. 392). B. a portion of the two innermost 

 ligneous circles of A, highly magnified : a.b.c. the tracks 

 of the buds conjoined, and connected with the medulla of 

 the branch. 



8. Wedge from the trunk of a Lilac, ten years old : e. a blighted 



bud. 



9. Longitudinal section of a bud of Lilac, three weeks after the 



protrusion of the branch on which it is seated : a. the em- 

 bryon of the future branch ; b. c. rudiments of the scales of 

 the bud. 



10. Transverse section of a twig of Lilac three years old, made 



immediately below an adventitious bud ; a. the origin of 

 the bud in the medullary sheath of the twig; b. outer 

 scales ; c. foliar scales, showing the transition from scales 

 to leaves; d. first leaf of the protruding branch. 



11. Transverse section of the root of the vine: . cuticle and 



