BIOLOGY OF THE FLOWER 193 



the Strawberry and the Rose. While the sepals and petals 

 are free and the stamens indefinite, as in the Buttercup, 

 these parts are developed on the edge of the hollow recep- 

 tacle ; they are therefore around, and not below, the ovary 

 thus being perigynous. The carpels are numerous and 

 apocarpous. 



The irregular flowers of the Sweet-Pea and Gorse also 

 have perigynous stamens, but only one (apocarpous) carpel. 



The Chervil flower is also irregular, but the sepals, petals, 

 and stamens are developed on the top of the ovary 

 (epigynous), the inferior ovary being syncarpous. 



In all these cases the petals are free (polypetalous). 



In the remaining examples the chief difference we noticed 

 was that the petals were united to form a tube (gamo- 

 petalous). 



In the Heath, the corolla is bell-shaped ; the anthers 

 possess small appendages or horns, and the pollen escapes 

 through pores. The ovary is superior. In the Primrose 

 the five petals are joined, forming a long, narrow tube to 

 which are attached five stamens. The superior ovary has 

 only one chamber with free-central placentation. The 

 corolla of the Speedwell is also gamopetalous, and on it 

 there are two stamens ; the ovary is superior and two- 

 celled. In the Daisy and Dandelion, the flowers, though 

 small, are massed together into a head, or capitulum. The 

 petals are joined, and the five stamens on them have their 

 anthers united round the style. The ovary is superior, and 

 when mature has only one chamber containing a single 

 ovule. 



It is upon such characters in the structure and arrange- 

 ment of the parts of the flower that the classification of 

 plants depends ; and it is by comparison of these characters 

 on the lines indicated that we gain an insight into plant 

 relationships. All the plants we have just considered agree 

 in a few broad characters. The vascular bundles of the 



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