92 KANSAS Academy of science. 



dry region, and compare them. Though these may all grow in the same latitude, or 

 even in the same State and county, they are so different as to be noticed immediately 

 by the very casual observer, while a botanist would be able to tell at once where the 

 plant grew — in a dry or a moist situation. 



It is because of this fact that we associate the stately palms, the graceful tree 

 ferns and the magnificent Victoria regias with the hot, moist climate of the tropics. 

 For the same reason, we associate deciduous trees, like the oak, elm, or hickory, the 

 dainty ferns and the fair, sweet water lilies of our own ponds, with the temperate 

 zone; or the pines, ferns, hemlocks and balsams with the colder parts of this zone. 

 If our imagination travels further and further northward, we think of the scant 

 vegetation of mosses and lichens, or the great fields of perpetual ice and snow, 

 covered with microscopic plant forms only. 



All these things point out and verify the law of the survival of the fittest; for we 

 know that the great, large-leaved, succulent plants of the south, with their tender, 

 naked buds, could not live where there was ice and snow. Nor would you expect to 

 find the vegetation of the warm, moist tropical regions so small, or the buds of trees 

 so carefully protected from frost and cold by varnished or wooly scales, when there 

 is no frost or snow. 



Every part of a plant has some use, and every peculiarity some advantage, so 

 that we could not expect any modified part for protection, when there is no need 

 for that protection. 



Thus, after years of evolution, (or adaptation, if you are pleased so to call it.) 

 the flora of each region has come into harmony with its environments, and we have 

 a type of plants best suited to their habitation. 



With these general principles m mind, we would scarcely expect to find any 

 large, thin-leaved plants out in the dry, arid regions of western Kansas. It is the 

 absence of these that perhaps impresses us most when we first become acquainted 

 with the flora of this section. 



Looking across the level prairies of Greeley county, everything seems to be a 

 dull, monotonous, grayish-green hue, instead of the vivid fresh green of our prairies 

 in eastern Kansas. Again, if we notice, the prevailing color of the flowers is yellow, 

 with a few dull, purplish-red ones intermixed. In fact, we are forcibly reminded of 

 our own autumn colors, though these are midsummer flowers. Are these colors 

 due to the higher altitude, dry climate, or the very cool nights, or to all three com- 

 bined? 



If we study more closely, we will notice that most of the plants are Compositie, 

 which are usually yellow or purplish, while the grayish tint of the prairies is largely 

 due to the hairiness of the leaves, as most plants are more or less hairy, scabrous 

 or resinous in this region. Indeed, one rarely finds a glabrous, thin-l^iaved plant, 

 and that is usually resinous or viscid. One will also find the leaves of almost every 

 plant either finely divided or very much reduced, many being very narrowly linear, 

 subulate, or even simple scales and spines. In fact, the whole plant is reduced, and 

 often less than one-fourth the size of sister species in the eastern part of our State. 



The fierce struggle for moisture is everywhere apparent, from the size and form 

 of the plants. Of course, that plant that can endure the burning sun and the hot 

 winds longest has the greatest advantage, thrives best, and usually crowds out its 

 less hardy companions that are unable to fit themselves so well to their environ- 

 ments. 



The following plants are the most noticeably condensed of the western Kansas 

 flora, and form very strong contrasts with Eastern species: 



First, in the order Cruciferse, instead of our ordinary Nasturtium sinuatum Nutt. 

 Sisymbrium canescens Nutt., and S. officinale Scop., we find there only two species 



