LOOSESTRIFE AAD PIMPERNEL. 



129 



we shall probably come to a very different 

 conclusion. Most of the primrose family, to 

 which both genera belong, have capsules 

 opening by valves ; only two or three pecu- 

 liar species, like the common pimpernel, the 

 bog pimpernel, and the tiny chaffweed, have 

 capsules opening by a lid which lifts off in a 

 single piece. Therefore the presumption is 

 that the latter forms are derived from the 

 former, and not vice versa y especially as the 

 valvular mode of opening is a common one 

 among all plants, while the transverse mode 

 is extremely unusual. 



But we have something more than such 

 a presumption ; we have an actual relic of 

 the earlier habit impressed st'll upon the very 

 structure of the pimpernel. If you look care- 

 fully into its half-ripe capsules (with a small 

 pocket lens, or even without one) you will see 

 five dark brown lines traversing the top of 

 the sphere, from the pole towards the equator, 

 exactly like the meridians on a globe. These 

 are the marks of the valves by which the 



