Botany of the Dahlia 2 5 



as they are so large that in a hreeze of wind they will 

 carry it a considerable distance. The adaptations 

 which many species in the Composite have for 

 helping them in their distribution are most wonderful , 

 and without doubt account for the fact that the 

 Composite contains a larger number of species than 

 any other order. The fruit in many instances is 

 peculiarly well-adapted for being distributed either by 

 the wind, as in the Dandelion and Dahlia, or by birds 

 and animals, as in the Bur-marigold. And not only 

 are the seeds of many species provided by nature with 

 the means to carry them long distances where they 

 may find new habitats, but, when they have reached 

 their destination, they are able, by means of barbs, to 

 work their way down through grass or any other 

 obstruction into the soil. 



In the Dahlia the receptacle is convex while the 

 plant is in flower, but becomes flat and often concave 

 in fruit. 



The Dahlia may under certain conditions be self- 

 pollinated. As already stated, the stigmas are large 

 and have to force their way through the staminal tube, 

 and in doing so rupture the anther cells. When they 

 emerge from the tube they carry up with them on 

 their stigmatic surfaces large quantities of the pollen,, 

 thereby exposing it to the necessary conditions for 

 causing fertilisation. To ascertain whether the Dahlia 

 is self - pollinated or not, a number were isolated 

 with a fine netting so as to exclude all, except the 

 very smallest insects, and in each case the plants 

 flowered freely and set seed. In this locality the 

 Dahlia is visited by the red-tail and other bees, which 

 will cause cross pollination and thus account for the 



