680 



BOTANY 



PART II 



For systematic purposes the fruits are of great importance. Each half of the 

 fruit has five ribs, beneath which the vascular bundles lie. The marginal ribs of 

 each partial fruit frequently lie close together at the septum or they may be 

 distinct ; they may resemble the three dorsal ribs or differ more or less from them. 

 Between the five primary ribs four secondary ribs are sometimes present. Usually 



FIG. 725. Cicuta virosa. Rhizome cut through longitudinally ( nat. size). Fruit (enlarged). 



POISOXOFS. 



furrows (valleculae) occur between the ridges, and beneath each furrow a large oil 

 duct (vitta) is found, extending the whole length of the fruit. On either side of 

 the carpophore a similar oil duct is present in the septum, so that each mericarp 

 has six of these vittae (Fig. 723, 1). In some species additional small ducts are 

 present (Fig. 723, 2, 3). The form of the fruit as seen in a cross section differs 

 according to whether the diameter is greater in the plane of the septum or at 

 right angles to this. The character of the marginal and dorsal ridges and the 



