older it buries itself the deeper, it also has seeds and pocls 

 specially fitted for easy distribution by the wind. These 

 characters of the bulbous plants point toward a colder climate 

 farther south than now, followed by a more arid and hotter 

 one. Since plants with herbaceous stems and perennial roots, 

 because of the excessive reduction of surface in winter, are 

 specially fitted to endure a climate with great contrasts be- 

 tween the seasons, we find them forming the bulk of the vege- 

 tation in the moist Temperate Zone. Curiously enough an- 

 nuals with the most reduction possible in surface are increas- 

 ingly scarce as we approach the Poles. This may be due to 

 the danger of the seeds rotting or starting in the fall because 

 of the moTsture, while no such danger confronts them in the 

 deserts. In our region perennials arc subjected to trying ex- 

 periences with freezing and thawing which are very harmful, 

 - they protect their buds and roots by a copious growth 



; hardy than those farther north where 

 tne snow forms a warm blanket which never leaves till spring 

 comes and therefore the buds do not protect themselves so 

 much. It is a fact that there is a wide belt in about our lati- 

 tude where spnng is much prolonged and therefore the season 

 of frost, but farther north the season is much shortened and 

 the danger of late frosts much lessened in relation to the be- 

 ginning of Spnng. This results in a narrow belt where the 

 raising of tender fruits is possible much farther north than 

 here, while there is a wide belt of uncertain crops to the south 



In a humid region where moisture is no object we find an 

 abundance of leaves and little or no economy used in their 

 structure, and little protection in the way of resin, gum, or 

 hairs, but in a desert region where moisture is a matter of 

 life or death we see every precaution use to save it The 

 leaves are small, often reduced to scales and the bark of the 

 stems performing the office of leaves, th leaves are mostlv 

 leathery, hairy, scaly, or resinous, and with elaborate devices 

 j>r reducing evanoration. Since in such regions the vegetation 

 IS scanty there has to be special protection against enemi'-^. 

 .nnd so we find an unusual development of spines, prickles, 

 ?:roiig odors, rough hairs, etc. 



