ON FRUITS AND SEEDS. 



161 



In other cases the plant throws its own seeds to some little dis- 

 tance. This is the case with the common Cardainine hi7'suta, a little 

 plant, I do not like to call ,^-^ 



it a weed, six or eight inches 

 high, which comes up of itself 

 abundantly on any vacant 

 spot in our kitchen-gardens 

 or shrubberies, and which 

 much resembles that repre- 

 sented in Fig. 17, but with- 

 out the subterranean pods d. 

 The seeds are contained in a 

 pod which consists of three 

 parts, a central membrane, 

 and two lateral walls. When 

 the pod is ripe the walls are 

 in a state of tension. The 

 seeds are loosely attached 

 to the central piece by short 

 stalks. Now, when the prop- 

 er moment has arrived, the 

 outer walls are kept in place 

 by a delicate membrane, only 

 just strong enough to resist 

 the tension. The least touch, 

 for instance a puff of wind 



Pig. 2. Viola hirta. a, young bud ; 6, ripe seed- 

 capsule. 



blowing the plant against a neighbor, detaches the outer wall, which 

 suddenly rolls itself up, generally with such force as to fly from the 

 plant, thus jerking the seeds to a distance of several feet. 



In the common violets, besides the colored flowers, there are others 

 in which the corolla is either absent or imperfectly developed. The 

 stamens also are small, but contain pollen, though less than in the 

 colored flowers. In the autumn large numbers of these curious flowers 

 are produced. When very young they look like an ordinary flower- 

 bud (Figs. 2 and 3, a), the central part of the flower being entirely 

 covered by the sepals, and the whole having a triangular form. When 

 older (Figs. 2 and 3, h) they look at first sight like an ordinary seed- 

 capsule, so that the bud seems to pass into the capsule without the 

 flower-stage. The pansy violets do not possess these interesting flowers. 

 In the sweet-violet ( Viola odorata and Viola hirta. Fig. 2) they may 

 easily be found by searching among the leaves nestling close to the 

 ground. It is often said, for instance by Yaucher, that the plants act- 

 ually force these capsules into the ground, and thus sow their own 

 seeds. I have not, however, found this to be the case, though, as the 

 stalk elongates, and the point of the capsule turns downward, if the 

 earth be loose and uneven, it will no doubt sometimes so happen. 



VOL. XIX. 11 



