THE FliUIT 



155 



342. The appendages of seeds seouiing dissemination by 

 wind are veiy siniilai' to tliose of fruits in many cases. 

 Compare, for instance, tlie seed of tlie Trumpet Creeper 

 (Fig. 276, a) witli tlie fruit of the Elm (Fig. 265) ; and 

 the seed of the Milkweed (Fig. 276, c), possessing a coma, 

 or tuft of hairs, witli the pappus-bearing achenu of the 

 Thistle (Fig. 262). 



343. Water. — Tlie fruits of tlio Cocoanut Palm are 

 originally covered with husks impermeable to sea water. 

 They sometimes fall into the ocean, and being carried 

 to distant strands are cast up by the waves and there 

 germinate. In a like manner the achenes of the Arrow- 

 liead QSagittaria) — a plant which is common along the 

 margins of ponds — buoj^ed up by the air-filled cells of 

 the pericarp, are floated to a distance. In a number of 

 species they float for a definite length of time ; tlien, 

 when germination is about to begin, they sink to the 

 biittom. 



344. Animals. — The fruits of many plants are thickly 

 set with liooks suited to catch in tlie fur of animals 

 (Fig. 280). The fruits are thus 



separated from the plant and car- 

 ried away, to be sul)se([uently re- 

 moved by the animals themselves 

 or brushed off accidentally. Nuts 

 hidden away in the ground by squir- 

 rels must occasionally l)e left to 

 grow, either througli oversight or 

 on occasion of the death of the de- 

 positor. Then again, edible fruits 

 like the Cherry, the A[)ple, and the berries offer to 

 animals a substantial reward in return for the service 

 of dispersal. 



345. Ejection of the seeds is not uncommon. The most 

 familiar example is tluit of tlie Jewelweed, or Touch-me- 

 not, the ripe jiods of whicli, wlien touclied, burst and 

 throw tlie seed in all directions. The bursting is due 

 to the sudden splitting asunder and coiling up of the 



280. The fruit of Agri- 

 mony. 



