EXPLANATION OF THE PLATES. 



PLATE I. 



Fig. 1. Section of the tubers of Orchis mascula: a. the new tuber; 

 b. the old ; e. the base of the stem of the present year's 

 herbage; d. the plantule or embryon; e. a sheath cover- 

 ing the plantule ; /. the point of conjunction of the ves- 

 sels of the stem of the old tuber, with those of the plan* 

 tule and the new tuber; g. a root. (p. 159, 161). 



2. A transverse section of the new tuber, to display the vessels 



injected, (p. 160). 



3. A transverse section of the old tuber, to demonstrate the 



effect of the absorption of the nutritious fluids on the cells 

 in the immediate vicinity of the vessels, (p. 160). 



4. Longitudinal section of a potatoe : a. the central part or 



pith ; b. b. b. b. the cortical part ; c. c. c. points where the 

 eyes or gems are situated ; d. point where the tuber was 

 attached to the runner, (p. 163). 



5. Bulbs of Crocus sativus; a. b. the new bulbs adhering 



closely to c. the old or parent bulb much shrivelled ; d. the 

 radical plate of the old bulb. (p. 167). 



6. Section of fig. 5 ; d. two cords of vessels, which separate 



from the general bundle immediately on entering the new 

 bulb, and pass ,on to supply nutriment to the embryons 

 e. which are forming on a. b. (p. 167, 169). 



7. Bulbs of Ixia polystachia ; a. b. the bulbs bearing the pre- 



sent year's herbage, partly covered with c. the reticulated 

 b 2 



