326 PLANT-LIFE 



growth, and even if they attained to the stature of a few 

 years' growth they would establish a state of congestion 

 in which no one of them would have " room to live." 

 Crowded slumdom is as bad for plants as for human 

 beings. The Sycamore has devised a better way; its 

 fruit has a pair of wings, and is popularly termed a key. 

 When it becomes detached from the tree it behaves like 

 a very light shuttlecock, spinning on its own axis, and 

 taking a zigzag course as it descends. It is frequently 

 driven a long distance before the wind, and may come 

 to earth, where it literally breaks new ground, and can 

 pursue a course of vigorous and successful growth. 

 With such provision for wind-dispersal of its fruits the 

 Sycamore avoids the evils of congestion, and enables its 

 kind to be perpetuated under favourable circumstances. 

 Attention to a few typical examples will help us to 

 form some definite conclusions as to the means of seed- 

 dispersal. If one sits in close proximity to some Gorse- 

 bushes on a dry sunny day in spring or early summer, 

 one may be assaulted by a fusillade of hard seeds. The 

 dry warmth causes the two valves of the seed-pod to 

 separate with a sharp crack, and when separated they 

 curl up with great rapidity, expelling the seeds and 

 shooting them to a considerable distance. The seed- 

 vessels of the Sweet Violet open into three equal valves, 

 which display the shiny seeds so that they may be dried 

 and hardened. When this has been accomplished, each 

 valve folds as if it worked on hinges, and the edges come 

 near to each other. Ultimately so much pressure is 

 brought by the valves on the glossy seeds that they are 

 discharged like shot, with sufficient impetus to carry 

 them several feet, or even yards. The smoothness of the 



