192 THE STORY OF THE PLANTS. 



fourth barricade; the device is efficient: the vetch 

 thus offers blackmail to creeping thieves in the 

 shape of stem-honey, in order to guard from their 

 depredations the far more valuable and useful 

 honey in the flowers, which is intended to attract 

 the fertilising insects. 



When the purple flowers have in due time 

 been fertilised, they produce long narrow pods, 

 each containing about a dozen round pea-like 

 seeds. As the pods ripen, the plant shrivels up, 

 and usually dies away, leaving only the ripe seeds 

 to represent its kind through the winter. But 

 sometimes, in damp and luxuriant autumns, the 

 stem struggles through the winter to a second 

 season, and flowers again in the succeeding sum- 

 mer. We express this fact as a rule by saying 

 that the vetch is usually an annual, but occasion- 

 ally a biennial. 



With most annuals, such as wheat or sunflower, 

 the whole strength of the plant is used up in the 

 production of seed ; and as soon as the seed is set, 

 the plant dies immediately. Where annuals have 

 the sexes on separate plants, however, the male 

 plants die as soon as they have shed their pollen, 

 their task being thus complete ; while the females 

 live on till their seed has ripened. 



Common coltsfoot is another well-known plant 

 whose life-history shows some points of great 

 interest. It grows in the first instance from a 

 feathery fruit, one-seeded and seed-like, which is 

 carried by the wind, often from a great distance. 

 These flying fruits alight at last upon some patch 

 of bare or newly-turned soil, such as the bank of 

 a stream where there has been lately a landslip, 

 or the side of a railway cutting. These bare sit- 

 uations alone suit the habits of the baby coltsfoot ; 



