4 THE BOOK OF NATURE STUDY 



is called an umbel, and the family of plants gets the name Umbelli- 

 ferae, from the prevalence in it of this type of inflorescence. It 

 will be found that at the end of the main stalk a number of thin 

 ribbed stems arise close together and diverge on all sides. Each 

 of these bears at its summit a number of stalked flowers, which 

 similarly form an umbel. Since the whole inflorescence is thus an 

 umbel of umbels, it is spoken of as a compound umbel. At the base 

 of each of the small umbels some small narrow green bracts will 

 be found. In the Cow-Parsnip these are few in number, and no 

 bracts are found at the base of the whole umbel. 



Each flower consists of a slender hairy stalk, which widens 

 out just below the flower into a somewhat flattened green body 

 also bearing coarse white hairs. This is the inferior ovary upon 

 which all the other parts of the flower stand. The most con- 

 spicuous of these parts are five white petals, but if the flower 

 is looked at from below with the lens indications of five minute 

 green teeth alternating with the petals will be seen. These are 

 the sepals, which in some plants of the family are better repre- 

 sented, in others even more completely reduced. The petals 

 are white, and the free edge of each is notched ; they are not joined 

 together. In the flowers towards the centre of the umbel all the 

 petals are about the same size, though even here the outer three 

 petals tend to be slightly larger than the other two. This is 

 much more marked in the outer flowers of each umbel, and 

 especially in the flowers that fringe the whole inflorescence. In 

 these the outermost petals are greatly enlarged, and assist in 

 rendering the whole group of flowers conspicuous. The five 

 stamens alternate with the petals (Fig. 2, A). In the bud they are 

 bent inwards, but as the flower opens their filaments straighten 

 and diverge, bearing the small greenish anthers. In the centre of 

 the flower is a two-lobed, yellowish-green swelling, from which 

 two short stalk-like styles, each ending in a small stigma, project. 

 The swelling around the bases of the styles is the nectary. As 

 the number of styles indicates, the inferior ovary is composed of 

 two carpels. It is more easily dissected when enlarging to form 

 the fruit, but can be studied quite well in the flower. If this is 

 cut in half (Fig. 2, B) the ovary will be seen to have two cavities, 

 in each of which a single ovule hangs. 



