The hazel and alder develop their flowers in the year preceding their opening. The female flowers of the hazel (Fig. 118) look somewhat like buds, but may be distinguished by the red stigmas. The fruit is a nut, enclosed by a sheath of soft bracts. The seeds are largely dispersed by squirrels. The alder grows on the banks of streams; its female flowers (Fig 119, b) are arranged in short catkins, which may be called cones. The ripe cone (5, Fig. 119) contains two nuts at the base of each scale. The fruits fall into the stream, and float away, perhaps to germinate at a considerable distance. [Pg 150] 31. THE WILLOW AND THE POPLAR. 1. The willow.—About the third week in March, examine willow trees, and notice the soft, round, silky bodies which spring alternately on the young twigs. On some trees these are broad and yellow; they are male catkins (Fig. 120). Pick off a flower and see the stamens (generally two stamens to each flower) inserted on a small silky bract (Fig. 121, B). With a lens look for the honey cup at the bottom of the bract. On other trees notice the long, narrow, silvery female catkins. Pick off a flower to see the single pistil with the forked style, also on a small, honeyed bract. Have you ever seen bees visiting the flowers? Are the catkins as conspicuous when the trees are in leaf? Is it an advantage to the trees to flower before the leaves come out? In June, examine the ripened female catkins. Pull out a tuft of the hairy seeds and dry it in the sun, noticing how they form a fluffy mass. Blow the mass of seeds. How do you think the seeds are dispersed? 2. The poplar.—Find male and female poplars and examine their flowers. Are the female flowers pollinated by insects or by the wind? Is self-fertilisation ever possible with willows and poplars? Why not? Which appear first, the flowers, or the leaves of poplars? Why? Examine the leaves of the English poplar. Why do they turn over so easily, even with a very slight breeze? Are both sides of the leaf of the same colour? Compare the Lombardy poplar with the English poplar.