58 THE BOOK OF NATURE STUDY 



composed of two carpels (Fig. 14, 4). Each stamen has a short 

 stalk and a purplish anther. The pistil consists of a somewhat 

 flattened ovary, which narrows gradually into the style ; this ends 

 in a rather large two-lobed stigma. There is no trace of either calyx 

 or corolla. Besides these flowers, which are provided both with 

 stamens which form pollen and a pistil capable of developing into 

 a fruit, two other kinds may be found. These may occur either on 

 the same or different trees. In one type which we can recognise as 

 a female or pistillate flower (Fig. 14, 4) the two stamens are present, 

 but their anthers never open and no pollen is shed. The anthers 

 soon drop off. The pistil is, however, well developed. In the 

 male or staminate flowers, on the other hand (Fig. 14, 6, 7), the pistil 

 is at most represented by a slender projection between the two 

 stamens, the anthers of which are practically stalkless. The 

 extremely simple type of flower in the Common Ash is evidently 

 due to reduction from a more complicated type, for other species 

 of the genus have flowers provided with a calyx. 



Pollination takes place by the help of the wind, the pollen 

 being shed in a powdery form and readily caught on the surface 

 of the large stigma. With this mode of pollination the absence 

 of a calyx and corolla and of any provision of nectar may be 

 associated. The flowers of the Ash may be instructively compared 

 with the insect pollinated ones of the Lilac, which is a closely 

 related plant. The ready transfer of pollen by the wind is facili- 

 tated by the flowering taking place before the foliage develops, 

 and the likelihood of pollen being often carried from one flower 

 to another is increased by the existence of male and female 

 flowers, as well as those with both stamens and pistil. 



The pistil is formed of two carpels, and the ovary is divided 

 into two cavities. In each of these are two small hanging ovules. 

 After flowering many of the flowers and often whole inflorescences 

 fall off, but the ovaries of others increase in size and become the 

 fruits. The hanging bunches of flat green fruits remain on the 

 branches for months, and are commonly known as " keys." Some 

 of the fruits are shorter and broader, and on dissection will be 

 found to contain no perfect seeds (Fig. 14, 12). In the longer 

 fruits, on the other hand, one of the ovules is developed into the 

 single seed (Fig. 14, n, 12, 13). This forms a swelling in the 



