12 WILD FLOWERS 



pieces, we find that it consists of four different kinds of organs. 

 To the outside there is a whorl (or circle) of five greenish scales : 

 these are sepals, and together make up the calyx, which in the 

 bud protects the delicate internal parts of the flower. Then 

 comes a whorl of yellow petals, forming the corolla : its bright 

 colour, and the fact that frequently, as in this case, there is to 

 be found honey about its base, induce insects to visit the flower. 

 Inside the corolla there is a large number of stamens; each of 

 these consists of a delicate stalk, and a little head, in which is 

 produced the dust-like pollen. Finally, in the centre is a 

 number of green grains, the seed-vessels : at the tip of the seed- 

 vessel is a receptive spot the stigma which is frequently borne 

 on a slender stalk the style. Before the flower can set seed, it 

 is necessary for the ovules, which are contained in the seed-vessel, 

 to be fertilised, and this can take place only if pollen from the 

 stamens reaches the stigma the receptive spot of the seed-vessel. 

 It has been found that better and more abundant seed is set if 

 the pollen be obtained from the flower of another plant, and it 

 is for the purpose of attaining this end that the plant invites 

 the visits of insects. These, in their hunt for honey, brush 

 against the stamens and stigma, and as they always carry about 

 a dust of foreign pollen, there is a considerable chance that the 

 stigma of a flower will receive pollen from one of its kind, 

 growing on a separate plant. 



The different parts of the flower may be arranged in different 

 ways : frequently a complete set of parts is wanting the wood 

 anemone, for example, has no corolla, but only a calyx, which 

 has become brightly coloured to take the place of the missing 

 petals. If either stamens, or seed-vessel, be absent, then two 

 kinds of flowers, one male with stamens, one female with seed- 

 vessels, are found, and sometimes on different plants. The 

 numbers of the parts vary greatly. Frequently the parts of a 

 whorl are united to form a single piece. The seed-vessel is often 

 embedded in the flower-stalk, below the other parts, instead of 

 being above them, as in the buttercup. 



The flowers may occur singly in the axils of the leaves, that 

 is, in the angle between the leaf and the stem ; but more fre- 

 quently they are grouped in characteristic inflorescences. By a 

 spike we mean, in this book, any elongated mass of flowers 

 occupying the apex of a stem or branch. By an umbel we 

 mean an inflorescence in which the stem or branch ends 

 abruptly, giving rise to a large number of flower -stalks, the 

 lengths of which are such that the flowers all occupy one level, 

 and so form a flat, pancake-like, or convex, umbrella-like group 

 (e.g. Figs. 6, 7). By a composite head we mean a close head of 

 flowers surrounded by a number of greenish scales or leaves 



