EXPLANATION OF THE PLATES. 



Fig. 10. A small portion of the above, highly magnified, to display 

 the nature of the vessels : a . the kind of sheath in which 

 the rings forming the vessels, b. b. b. are enclosed. 



11. The articulation of the culm of Triticum testivum split: . 



the lower joint terminating in a sheathing leaf; b. the 

 new joint, (p. 300). 



12. The cuticle of the culm of Triticum cestivum, to demonstrate 



its respiratory pores, (p. 302). 



13. The cuticle of Juncus conglomerate: a. a. portions which 



cover the striae, and which are devoid of respiratory pores ; 



b. portion between the striae thickly studded with pores, 

 (p. 302). 



14. Transverse slice of an apple twig (copied from Mr. Knight's 



plate in the Philosophical Transactions} ; a. the bark ; b. the 

 alburnum or young wood ; c. the pith. 



15. A terminal twig of ^Esculus Hippocastanum split down the 



middle ; a. the pith ; b. the wood ; c. the cortex ; d. e. buds 

 or gems ; /. g. the bases of the petioles of two leaves, 

 which are cut off; h i. cords of vessels connecting the pe- 

 tiole with the stem ; k. terminal leaf bud. (p. 316.) 



PLATE VI. 



2. A. A thin transverse slice of a twig of ^Esculus Hippocas* 



tanum: B. the dark-coloured portion of the slice A, sepa- 

 rated, and very highly magnified; a. the cuticle; b. ex- 

 terior layer of the cellular integument ; c. interior layer of 

 the cellular integument; d. vascular layer of the cortex 



c. liber ; * alburnum in its first stage ; /. perfect wood ; g. a 

 divergent layer; A. large vessels of the wood; t. medullary 

 sheath; k. pith. (p. 319 406). 



3. A transverse slice of a twig of Sambucus nigra in the first 



year of its growth, (p. 336). 



4. Slice of a two years' old branch of Sambucus nigra. (p. 336). 



5. Slice of a three years' old branch of Sambucus nigra. (p, 



336). 



