DISTRIBUTION OF SPORES AND SEEDS. 279 



over the ground or to bury themselves in it when alternately 

 moistened and dried (fig. 241). The seed vessel of the 

 squirting, cucumber is so distended by the almost liquid pulp 

 surrounding the seeds that it ejects the mass through the 

 opening formed by its separation from the stem. 



397. 2. Distribution by water. — In some plants 

 this is secured by the fact that the fruits open only 

 when moistened. In such cases the seeds may be either 

 washed out from the opening pods by rain, or may be 

 loosened in many other ways. The seeds are thus set 

 free at the time best suited to their prompt germination. 

 Some plants, adapted to dis- 

 tribution by water, are pro- 

 vided with floats. These 

 floats may consist either of 

 the enlarged and bladdery 

 seed pod (or some portion of 

 it), or of the spongy, air- 

 filled seed coat. The fruits 

 or seeds are thus made more 

 buoyant and float upon the 

 surface instead of sinking as 

 usual. Naturally, water-lov- 

 ing plants are chiefly adapted 

 to distribution in this manner. 



398. 3. Distribution by 

 winds. — Some plapts which 

 secure their distribution by 

 winds are only lightly attached 

 to the soil at maturity, so that they are readily uprooted and 

 carried bodily, when dry, for considerable distances by the 

 wind. The transfer is facilitated by the incurving of the 

 branches upon drying, so that the uprooted plant is more or 

 less spherical in outline, or by the fact that the plant is nor- 



F'lG. 241.- 



Pieces into which the fruit of 

 storksbill breaks. There are five of 



these each corresponding to a carpel and 

 arranged on the sides of a prolonged 

 torus as in ^ , fig. 240. A, when dry the 

 beak is si^irally coiled ; B. when moist. 

 The base is hard and very sharp. Magni- 

 fied about 2 diam. — After Noll. 



