EXPLANATION OF THR PLATES. 



b. b. b. b. arches formed by the inosculation of the vas- 

 cular fasciculi of the principal costae. (p. 572.) 

 Fig. 3. Appearance of the cuticular pores ; and the course of the 

 lymphatics on the inferior disk of the leaf of Hoy a 

 camosa. 



4. Appearance of the cuticular lymphatics on the superior 



disk of the leaf of Hoya carnosa. (p. 605). 



5. Leaf of Dionaea muscipula: a. three stiff setae on the su- 



perior disk of each lobe of the trap-like appendage ; 6. 

 setae on the margin of the appendage ; c. the proper leaf. 



6. One of the setae of the disk of the appendage highly mag- 



nified ; a. the base, which is cellular, and continuous with 

 the cuticle of the lobe on which it is seated ; b. the bristle, 

 which is rigid. 



7. Transverse section of the articulation between the chan- 



nelled part of the petiole and the leaf, in Phaseolus tw/- 

 garis: a. the whole of the vascular fasciculi collected into 

 one central fasciculus. 



8. Transverse slice of the channelled part of the petiole, in 



Phaseolus vulgaris: a. a. a. vascular fasciculi forming a 

 circle within the cutis; b.b. two distinct fasciculi, (p. 

 577). 



9. Cuticle of the inferior disk of the leaf of Rumex acetosa: 



a. a. cuticular pores ; b. b. lymphatics. 



10. Cuticle of the superior disk of Rumex acetosa : a. cuticu- 



lar pore ; b. lymphatic. 



11. Transverse slice of a portion of the expansion of a leaf of 



Zea Mays: a. a. cuticle; b. the parenchyma or substance 

 of the leaf; c. c. one of the visible costae ; d. e. d. e. d. fas- 

 ciculi of vessels not visible on the surface of the leaf; 

 /./. two spaces, more cellular than the rest of the leaf, 

 guarded on each side by short, subulate spines, (p. 561). 



12. Transverse slice of the petiole of Trapa natans : a. a. the 



vacuities, which are filled with air ; b. b. b. diaphragms 

 which separate one vacuity from another, in the length of 

 the petiole ; c. vascular fasciculi occupying the centre of 

 the petiole, (p. 596). 



