How Seeds and Fruits are Scattered.--Seed dispersal is accomplished in many different ways. Some plants produce enormous numbers of seeds which may or may not have special devices to aid in their scattering. Most weeds are thus started "in pastures new." Some prolific plants, like the milkweed, have _seeds_ with a little tuft of hairlike down which allows them to be carried by the wind. Others, as the omnipresent dandelion, have their _fruits_ provided with a similar structure, the pappus. Some plants, as the burdock and clotbur, have fruits provided with tiny hooks which stick to the hair of animals, thus proving a means of transportation. Most fleshy fruits contain indigestible seeds, so that when the fruits are eaten by animals the seeds are passed off from the body unharmed and may, if favorably placed, grow. Nuts of various kinds are often carried off by animals, buried, and forgotten, to grow later. Such are a few of the ways in which seeds are scattered. All other things being equal, the plants best equipped to scatter seeds or fruits are those which will drive out other plants in a given locality. Because of their adaptations they are likely to be very numerous, and when unfavorable conditions come, for that reason, if for no other, are likely to survive. Such plants are best exemplified in the weeds of the grassplots and gardens. REFERENCE BOOKS ELEMENTARY Hunter, _Laboratory Problems in Civic Biology_. American Book Company. Andrews, _A Practical Course in Botany_, pages 250-270. American Book Company. Atkinson, _First Studies of Plant Life_, Chaps. XXV-XXVI. Ginn and Company. Bailey, _Lessons with Plants_, Part III, pages 131-250. The Macmillan Company. Coulter, _Plant Life and Plant Uses_. American Book Company. Dana, _Plants and their Children_, pages 187-255. American Book Company. Lubbock, _Flowers, Fruit, and Leaves_, Part I. The Macmillan Company. Newell, _A Reader in Botany_, Part II, pages 1-96. Ginn and Company. ADVANCED Bailey, _Plant Breeding_. The Macmillan Company. Campbell, _Lectures on the Evolution of Plants_. The Macmillan Company. Coulter, Barnes, and Cowles, _A Textbook of Botany_, Part II. American Book Company. Darwin, _Different Forms of Flowers on Plants of the Same Species_. Appleton. Darwin, _Fertilization in the Vegetable Kingdom_, Chaps. I and II. Appleton. Darwin, _Orchids Fertilized by Insects_. D. Appleton and Company. Mueller, _The Fertilization of Flowers_. The Macmillan Company. V. PLANT GROWTH AND NUTRITION. CAUSES OF GROWTH