APRIL. 8 1 



plants really represent the survival of the fittest in this 

 struggle against man and those forms which he cultivates. 



Our little bitter-cress is one of these specially-developed 

 plants, and it is noteworthy that part of its adaptation 

 consists in having its flowers degraded so as to he capable 

 of self-fertilisation, and thus independent of insects. Tn 

 poor soil it forms little rosettes of leaves lying close to the 

 ground, the whole plant being not more than from half to 

 one inch in diameter. In better soils it reaches as much as 

 six inches in height, but it is always a small plant, with 

 numerous small leaflets, which have a taste and smell like 

 that of cress. The flowers are produced on short stalks, 

 and are so minute as to be frequently unnoticeable. Usually 

 the first indication they give of their existence is the 

 development of their seed-pods. The common form of 

 flower in a crucifer, as seen in the turnip, cabbage, or 

 honesty, has four green sepals, four coloured petals, six 

 stamens, and a two-celled ovary. In the much retrograded 

 form of Cardamine there are four sepals and an ovary, but 

 the petals are either totally wanting or are very much 

 reduced, while only one or two stamens are produced. 

 As the flower is self-fertilised there is no need for attrac- 

 tive petals, while a single stamen probably supplies more 

 than sufficient pollen to fertilise all the ovules in the ovary. 

 However prolific and even wasteful nature may sometimes 

 seem to us to be and she does seem to be lavishly so in 

 many cases which we do not fully understand we yet find 

 a principle of the strictest economy running through all 

 her developments. Unnecessary organs tend always to 

 become atrophied or to disappear, and hence we find in 

 a flower which does not need to open in order to be fertil- 

 ised, that four or five of the normal six stamens are 

 superfluous and therefore are not developed. 



The seed-pods ripen very rapidly, a few days is all they 

 need. Then if the plant be taken hold of to pull it out of 

 the ground, snap go the small pods like miniature popguns, 

 and a shower of little seeds is heard to fall all round. Truly 

 it is an aggravating little weed. You have a flower border 

 beautifully clean, and flatter yourself that it will not need 

 F 



