92 STRAWBERRY, AGRIMONY. [chap. 



selves and the pistil. They are very much frequented 

 ty insects, and as the stamens ripen gradually, and 

 from the outside inwards, there is a considerable in- 

 terval during which, though the pistil is mature, and 

 some of the anthers are ripe, self-fertilisation is diffi- 

 cult ; while from the great frequency of insect visits, 

 fertilisation is generally effected before the inner 

 anthers are mature. 



In the Strawberry (Fragaria vescd) also, the stigma 

 arrives at maturity some time before the anthers, so 

 that cross-fertilisation generally takes place. The 

 species of Potentilla agree with Fragaria in habit, 

 foliage, and flowers, but the fruit is not succulent. 

 The honey, however, is not secreted in drops, but 

 forms a thin layer. Agrimonia Eupatoria appears to 

 secrete no honey, and is but seldom visited by insects. 

 Alchemilla vulgaris is remarkable for variability. The 

 honey is scanty, so that it is little visited by long- 

 lipped insects ; while, from its greenish colour it is not 

 attractive to beetles, or other colour-loving species. 

 Self-fertilisation is, however, comparatively rare, since 

 the flowers seldom possess both anthers and stigmas ; 

 one or the other being generally more or less rudi- 

 mentary. This plant, therefore, may be considered 

 to be becoming dioecious. 



The next two genera of Rosacese, Sanguisorba and 

 Poterium, each of which contains a single British 

 .species, have been already alluded to in the opening 

 chapter (anti p. lo). Sanguisorba (Fig. lo) officinalis 

 is monoecious and fertilised by insects. In Poterium 

 sanguisorba (Fig. 9) some flowers are male, some 

 female, and some hermaphrodite, and the pollen is 



