in.] THE FERTILISATION OF FLOWERS. 49 



it visited a short-styled flower, would be likely to 

 touch against the stigma ; or if it first visited a short- 

 styled flower, its head would strike against the anthers, 

 and, when visiting a long-styled flower, deposit the 

 pollen so obtained on the stigma. 



More remarkable, perhaps, in this respect is the 

 Purple Loosestrife (Lythrum salicarid), in which three 

 forms occur. In the first form the pistil is very long 

 and the stigma is far above the anthers, which are in 

 two sets six of them being about two-thirds of the 

 length of the pistil, and six about one-third. In the 

 second form six stamens are as long as No. I's 

 pistil, whilst No. 2's pistil is two-thirds of that length, 

 and the other six stamens are one-third. In the 

 third form the pistil corresponds in length with the 

 short stamens in the other forms, whilst one set of 

 stamens are of the length of No. 2's pistil, and the 

 other set agree with the pistil of No. I. The long 

 stamens produce large pollen grains to fertilise the 

 long pistils ; the short stamens produce small pollen, 

 and the middling-size stamens produce pollen of a 

 size half-way between these two extremes. 



Most Umbelliferous plants such as the Carrot, 

 Parsley, Parsnip have very small flowers, inconspi- 

 cuous individually, but from the manner in which 

 they are associated in large flat heads, they are 

 among the most noticeable objects of the hedgerows. 

 They are fertilised chiefly by small insects to whom 

 the honey is easily accessible, it being secreted on a 

 flat open disc, and therefore it is inaccessible to Lepi- 

 doptera and bees with long trunks. At first only the 

 anthers are mature, but when they have shed their 



