XX EXPLANATION OF THE PLATES. 



cuticle ; b. b. large fasciculi of proper vessels ; c. cellular 

 integument ; d. d. larger fasciculi of sap or spiral vessels ; 

 e. a smaller fasciculus of sap vessels, accompanied with 

 two fasciculi of proper vessels ; /. cellular pulp. 

 Fig. 9. Longitudinal section, passing through the centre of fig. 8. : 

 a. cellular mass of the cortex ; b. fasciculus of proper ves- 

 sels; c. slip of cellular matter; d. oblong cells; e. fasci- 

 culus of sap or spiral vessels ; /. oblong cells ; g. pith ; h. 

 condensation of the pith, forming a part of the septum in 

 this hollow stem. 



10. Transverse section of the petiole in Syringa vulgaris: a. the 



cortex ; b. cellular parenchyma ; c. c. small distinct fasci- 

 culi of sap vessels ; d. spiral vessels forming the central 

 fasciculus ; e. proper vessels, exterior to the sap vessels, (p. 



575). 



11. Transverse section of the petiole in Sambucus nigra; 



a.a.a.a.a. distinct fasciculi of proper vessels; b.b.b.b.b. 

 distinct vascular fasciculi, consisting of spiral and proper 

 vessels, (p. 576). 



PLATE IX. 



1. A hairy stem. (p. 269). 



2. A hispid stem. (p. 270). 



3. A shaggy stem. (p. 270). 



4. A woolly stem, Ballota lunata. (p. 270). 



5. A silky stem. (p. 270). 



6. A warty stem, Euonymus verrucosus. (p. 272). 



7. A vesicular stem, Mesembryanthemum crystallinum. (p. 272). 



8. None. 



9. None. 



10. Simple hairs; a. b, long flexible hairs, which produce pi- 

 lose, woolly, and shaggy surfaces, very highly magni- 

 fied, to demonstrate their articulated character ; <?. the 

 slight, subulate, inclining hair, which produces the silky 

 surface, (p. 639). 



