142 THE ROMANCE OF SEED-SOWING. 



become dr}', and contract, the two edges approaching each other. 

 This, after a time, forces the seeds out with a jerk, throwing 

 them eight or ten feet off. In Sweet Violet and Hairy Violet 

 ( V. odorata and hirsuta), the capsules are not so raised, the stem 

 being almost absent, and the leaves all springing from close to the 

 root. Here, we find that their capsules simply open as they he 

 on the ground, suffering the seeds to fall out among the grass 

 near by. Not being raised aloft, if the capsules shot their seeds, 

 the latter would probably strike against the surrounding grass and 

 fall back again, so the valves develope no contracting power, such 

 being useless, and they simply open quietly. Dog Violet has 

 found a better device for dispersion, and so in many generations 

 has gradually developed a tall stem, from the top of which its 

 elastic capsules can do their work with good effect. 



In Common Balsam, or 'Touch-me-not,' the pod dehisces 

 through its whole length, and at maturity, if we gently press the 

 centre between the thumb and finger, it swells up under our touch, 

 parts suddenly, and away go the seeds. I have stood at one end 

 of a room twelve feet long, and by pressure caused a pod to throw 

 its seeds with force against the opposite wall. Again, go and look 

 at some of our Vetches, or at Broom in seed-time, and you will 

 find the pods split in two, with each half rolled or twisted on 

 itself, and the seeds gone. The pods possess a layer of woody 

 tissue at an acute angle to their axis. When this contracts, the 

 pod is, therefore, not curled up along its length, but twisted, like 

 a screw. Gorse, and some others of the Pea Order, open 

 with a sudden crackling noise, and shoot out the seeds. On a hot 

 August day you may stand by a clump of Gorse bushes and hear 

 a series of tiny reports, as one by one the pods burst. 



Two singular instances are worth notice. The fruit of the 

 Sand-box tree {Hura crepitans) of America is about as large as 

 an orange, with a dozen or more deep furrows, which indicate 

 as many internal divisions into carpels. When ripe, and under a 

 hot sun, each separate carpel splits simultaneously, the whole 

 bursting with a loud explosion. From this fact, the plant has 

 earned the soubriquet of the ' Monkey's Dinner-bell ' ! 



Squirting Cucumber {Ecbaliuju elaterium) is one of the 

 Gourd Order, and when ripe is full to tension of a viscid fluid. A 



