BUTTERCUPS ; A STUDY OF SPECIES 297 



culus or buttercup genus have a gland on the petal and 

 many one-seeded carpels. 



It will next be desirable to arrange the plants of the 

 buttercup genus in the best order. One reason for doing 

 this is that it is much easier to find the accepted name of 

 any species if the descriptions are methodically arranged, 

 but naturalists are not satisfied with an arrangement 

 which is merely convenient for purposes of naming ; they 

 like to get what they would describe as a natural arrange- 

 ment. It is not very difficult to. divide the buttercups 

 into small groups, which seem to be tolerably natural. 

 We recognise : (i) The water-buttercups, which grow in 

 or close to water, and have nearly always both float- 

 ing and submerged leaves, besides white petals ; (2) the 

 spearwort-buttercups, which have flowers both in form 

 and colour almost precisely like those of ordinary butter- 

 cups, but undivided leaves ; (3) buttercups with deeply 

 cut leaves and yellow flowers ; (4) the celandine-buttercup, 

 with undivided leaves, and flowers like those of other 

 buttercups, except that the sepals and petals are more 

 numerous. The water-buttercup and the celandine-butter- 

 cup are the most peculiar of the four sets, and it will be 

 convenient to put one at the beginning, the other at the 

 end of the series, while the spearwort-buttercups and 

 the ordinary buttercups may occupy a place in the middle 

 (see Diagram B, p. 300). 



Let us now for the sake of further practice see how 

 we can arrange all the species of these groups in a natural 

 sequence. The leaves, as we have seen, distinguish the 

 two spearworts, for in these two they are undivided, 

 whereas in most other buttercups they are much cut. 

 The great spearwort-buttercup has large flowers, two 

 inches across, and the leaves are not stalked. In the 

 lesser spearwort the flowers are much smaller, and the 

 leaves are borne on stalks. 



There are several common buttercups which can be 

 distinguished from one another. We might divide them 



