The flowers of rushes in many respects resemble those of the lily family. Indeed it is supposed that the ancestors, not only of the lily family, but also (along a different line) of the grasses and sedges, were primitive and now extinct rushes. The lilies have developed the rush perianth more and more as they have increasingly depended on insects for pollination; while in the grasses and sedges the perianth has gradually dwindled because these plants found that wind-pollination was sufficient for their needs. [Pg 139] EXERCISES ON CHAPTER VII. 1. What grasses are grown as corn in your part of the country? How can you recognise the grasses (a) before flowering, (b) in the ear, (c) by the straw? 2. What forage grasses are most cultivated in your part of the country? Make a list of the earliest dates on which you have seen each in flower. 3. Examine grains of wheat, barley, oats, and rye, as harvested. In which of these are the pales present? What is the “beard” of barley? 4. Make a collection of “seeds” of various grasses, and write down the characters by which they may be distinguished from each other. 5. What are the commonest weeds you have seen in corn fields? Do the corn and the weeds flower at the same time or not? Is the time of flowering an advantage (a) to the weeds, (b) to the farmer? 6. In what important respects do wind-fertilized flowers differ from insect-fertilized flowers? Give examples of each. (1898) [Pg 140] CHAPTER VIII. COMMON FOREST TREES. 30. THE OAK FAMILY. 1. The oak.—(a) Habits of growth.—Examine an oak tree growing in an exposed situation. What is its approximate height? Estimate the diameter of the trunk at (a) the ground level, (b) at heights of 1, 2, 3, 4, etc., feet. At what height do the principal boughs come off? About what angle do the boughs make with the trunk? Are they straight, evenly curved, or zig-zag? Contrast in these respects an oak growing in a plantation. Try to account for the differences observed. (b) The bark.—Examine the barks in oaks of various ages. Do the ridges and furrows caused by the splitting of the bark form any definite pattern, or are they arranged anyhow? Find a piece which shows the pattern well, and make a drawing of it. (c) Method of branching.—Carefully observe the tree from a distance, and notice how the great boughs spring from the trunk, and in their turn give rise to smaller and smaller branches. Notice the shape of a tuft of the smallest twigs against the sky; then close your eyes and try to recall the picture. A still better way is to make a careful drawing of the tree, not attempting to put in details, but paying special attention to the trunk and main branches, and to the general massing of the twigs. What is the general “expression” of the tree? Would you call it, e.g., graceful, formal, sturdy, delicate, stiff, or sombre? The method of branching is best seen in the winter or spring, when the tree is leafless. [Pg 141]