THE DURATION OF PLANTS 387 



perpetuate themselves by means of tubers or other 

 thickened parts, but both root and stem die upon 

 the approach of the inactive season, or of winter. 

 These are pseud -annuals. 



490a. Pseud -animals (" false - annuals " ) are those which normally 

 die at the approach of winter, except that the kind is perpetuated by 

 means of bulbs, corms, tubers, and the like. 



491. Parsnips and salsify remain in the ground 

 all winter and flower the second season, and die. 

 Turnips and carrots may do the same where the 

 climate is not too severe. But parsnips, turnips, 

 carrots and radishes may "run wild," in which case 

 they may produce no crown -tubers, and may produce 

 seed and die the first year. They are only poten- 

 tial biennials, the biennial character seeming to be 

 largely the result of domestication. 



492. We have already learned that bulbs and 

 other thickened parts are storehouses of plant- 

 food, and that they are means, or adaptations, for 

 carrying the plant over an uncongenial season. 

 We have seen, too (489), that plants may be an- 

 nuals in one climate and perennials in another; 

 or annuals under one set of conditions and bien- 

 nials under another. It is now believed that the 

 duration of the plant is generally the result of ad- 

 justment to the circumstances in which it lives or 

 has lived. 



