24 KANSAS ACADEMY OF SCIENCE. 



Upon the same principle, a very convenient pipet may be constructed, by slip- 

 ping a short piece of rubber tubing over one end of a glass tube which has the other 

 end drawn to a small opening. The open end of the rubber tube should be closed 

 by a piece of cork. 



VARIATIONS IN DOMINANT SPECIES OF PLANTS. 



M. A. CAELETON, MANHATTAN, ASSISTANT BOTANIST, KANSAS EXPERIMENT STATION. 



One of the most important propositions offered by Mr. Darwin, in discussing 

 the subject of "Variations in Nature," is, that "wide-ranging, much-diffused and 

 common species vary most."* One would naturally suppose that such a proposi- 

 tion, if true, could be easily demonstrated by many illustrations from nature, seeing 

 that so many of our native species are far-reaching in their habitat, extending over 

 vast areas of the United States, and even of the American continent, encountering 

 an endless variety of soils and extreme changes of temperature and moisture. 



For the purpose of ascertaining how far such a demonstration could be carried 

 out from a study of the most common and widely diffused of our Western species of 

 flowering plants, I have gathered together such notes of original observation and 

 material from reports of other writers as form the basis of this paper. Not having 

 determined upon such a purpose, however, until late in the summer season, I have 

 only collated sufficient material for a preliminary discussion of the subject. 



The first thing to impress the careful observer is the fact, often repeated, that 

 that there is variation everywhere, and the more carefully one observes the greater 

 the amount of variation that is noted, until it appears to be entirely without limit 

 and becomes extremely delicate and infinitesimal, such as would be wholly over- 

 looked by the indifferent observer. 



It may be convenient to look upon the differences arising through variations as 

 being of several grades, namely, individual, varietal, specific, generic, etc., corre- 

 sponding to the different terms individual, variety, species, genus, etc., used in the 

 classification of the living forms, although the former shade into each other exactly 

 as do the latter. 



In discussing the subject at hand, I shall have mainly to do with varietal differ- 

 ences, which, however, are simply individual differences increased, and finally made 

 permanent, through the power of hereditary transmission. 



Species of plants tend to accommodate themselves, through variation princi- 

 pally, to four different changes of environment — changes of soil, moisture, light, 

 and temperature. As the territory covered by the notes and observations of this 

 paper is comparatively small, including Kansas, Indian Territory, as far as the 

 Canadian river, Panhandle, Texas, and eastern Colorado (although references will 

 be made at times to other districts), the elements of light and temperature will not 

 be so important as those of soil and moisture. 



I shall now continue the immediate discussion of my subject under four differ- 

 ent heads: (1) Variations in size, that is, of the entire plant, or any part of it; (2) 

 variations in morphology; (3) variations in the character of the trichomes, or sur- 

 face appendages; and (4) variations in color, mainly of the flower. 



* Darwin "Orlf^ln of Species," ch. 11, p. 42. 



