COTYLEDONS. 



619 



The fruits of the Stork's-bill (Erodium) get planted in the same way as those 

 of the Feather-grass. The five mericarps (or fruit segments) in this plant detach 

 themselves in a very characteristic manner from their support, as may be seen 

 in fig. 147 ^. First the lower thick end inclosing the seed splits off, and later 



Fig. 147.— Showiug the boring of fruits into the ground. 

 1, 2 Fruits of the Feather-grass (Stipa pennata). ^, * Fruits of the Stork's-biU {Erodium Cicutarium). 



also the long drawn-out point of the carpel. A part of the latter twists up 

 spirally, and only its free end stretches out in a slight curve, like the hand of a 

 watch. It is well known that this fallen fruit-segment is used as a hygrometer. 

 It is placed with its lower thick end which, like the fruit-end of the Feather-grass, 

 possesses a sharp point, on a board covered with paper, in the centre of a circle. 

 Marks are made on the circumference of the circle corresponding to the position 



