144 HETEKOSTYLED TKIMOEPHIO PLANTS. CHAP. I\. 



examined. Some artificially fertilised short- and long- 

 styled capsules produced a greater number of seeds than 

 was ever observed by me in wild plants of the same 

 forms, but then I did not examine many of the latter. 

 This plant, I may add, offers a remarkable instance, how 

 profoundly ignorant we are of the life-conditions of a 

 species. Naturally it grows " in wet ditches, watery 

 places, and especially on the banks of streams," and 

 though it produces so many minute seeds, it never 

 spreads on the adjoining land ; yet, when planted in my 

 garden, on clayey soil lying over chalk, and which is so 

 dry that a rush cannot be found, it thrives luxuriantly, 

 grows to above 6 feet in height, produces self-sown 

 seedlings, and (which is a severer test) is as fertile as 

 in a state of nature. Nevertheless it would be almost 

 a miracle to find this plant growing spontaneously on 

 such land as that in my garden. 



According to Vaucher and Wirtgen, the three forms 

 coexist in all parts of Europe. Some friends gathered 

 for me in North Wales a number of twigs from 

 separate plants growing near one another, and clas- 

 sified them. My son did the same in Hampshire, and 

 here is the result : 



TABLE 22. 



If twice or thrice the number had been collected, 

 the three forms would probably have been found 

 nearly equal ; I infer this from considering the above 

 figures, and from my son telling me that if he had 



