DISPERSION OF SEEDS 



147 



vegetation on isolated coral islands of the Laccadives 

 and Maldives is due to the possession of such devices 

 in the coats as have been described above. The first 

 vegetation that covers the face of islands newly raising 

 their heads above the surface of the ocean is no doubt 

 due to wind- and water-transported seeds of flowering 

 plants and spores of flowerless ones. < 



Many fruits burst with a sudden jerk or explosion, 

 so as to scatter the seeds to a great distance. Dopati 

 (see fig. 79), amrul, bharenda or €astor-oil, and 

 sheuli are very common in- 

 stances. How the capsules 

 of dopati burst and the 

 valves recoil and twist spir- 

 ally, scattering the seeds, is 

 a very familiar example. In 

 most of the large- flowered 

 Geraniums the beaks of the 

 fruit in coiling contract with 

 such suddenness that the 

 cocci, with enclosed seeds, 

 are shot out of the fruits, 

 which rupture septicidally 

 (fig. 127). Similarly, in 



many Acanthacece, such as Rungia parviflora, Diclip- 

 tera Roxburghiana, and Phaylopsis parviflora^ while 

 the capsules dehisce the placentas separate elastically 

 from the valves to scatter the seeds. 



For the purpose of dissemination through the 

 agency of animals, various devices are met with in 

 fruits and seeds. Many seeds and fruits are provided 

 with hooks, burs, or rough or sticky coats, by which 

 they attach themselves to animals and are transported 

 from place to place, as the hooked fruits of bag- 

 nakha {Martynia diandra) (fig. 128), th^ rough fruits 



Fig-. 127. — A, Pistil, and B, fruit of 

 Geranium 



