INTRODUCTION. XXVli 



One more example will suffice. The plant to be 

 examined is a small herb with somewhat fleshy leaves 

 and white flowers, with 6 stamens, four long and two 

 short. Had they been all of equal length we should have 

 had no hesitation in referring the plant to the Class 

 HEXANDRIA ; but as this is not the case, we turn kvthe 

 Class TETRADYNAMIA (p. xlix). Here we find that " all 

 the plants in this class belong to the CRUCIFEROUS TRIBE, 

 p. 36." On turning to the reference, we learn that the 

 division of this TRIBE corresponds with that of the 

 Linncean Class, namely, into plants bearing silicles 

 and those bearing siliques. The plant in question bears 

 a silicle, or pouch, and must be searched for in the group 

 "-\-Pouch 2-valved, with a central vertical partition." 

 Thlaspi and Capsella are passed over, as having fiat 

 pouches ; Hutchinsia and Teesdalia have a keeled pouch, 

 the cells of which are 2-seeded ; in Lepidium the 

 valves of the pouch are keeled, and the cells 1 -seeded ; 

 but in Cochlearia the pouch is globose, or nearly so, the 

 valves are not flattened, and the seeds are numerous. 

 Our plant, then, is a Cochlearia; and on turning to 

 genus 6 (p. 46), we find that our specimen, which has 

 an egg-shaped pouch and triangular leaves, is C. Ddnica 

 (Danish Scurvy- Grass). 



