fiber, cottonseed oil, a substitute for olive oil, is made from the seeds, and the refuse remaining makes an excellent cattle fodder. Cotton Boll Weevil. The cotton crop of the United States has rather recently been threatened with destruction by a beetle called the cotton boll weevil. This insect, which bores into the young Map showing the spread of the cotton boll weevil. It was introduced from Mexico about 1894. What proportion of the cotton raising belt was infected in 1908? growth of the fruit The loss in Texas The boll weevil, pod of the cotton, develops there, stunting the to such an extent that seeds are not produced. alone is estimated at over $10,000,000 a year. because of the protection offered by the cotton boll, is very difficult to exterminate. The weevils are destroyed by birds, the infected bolls and stalks are burnt, millions are killed each winter by cold, other insects prey on them, but at the present time they are one of the greatest pests the south knows. The control of this pest seems to depend upon early planting so that the crop has an opportunity to ripen before the insects in the boll grow large enough to do harm. Ultimately the boll weevil may do more good than harm by bringing into the market a type of cotton plant that ripens very early. Vegetable Fibers. Among the most important are Manila hemp, which comes from the leaf-stalks of a plant of the banana family and true hemp, which is the bast or woody fiber of a plant cultivated in most warm parts of the earth. Flax is also an important fiber plant, grown largely in Russia and other parts of Europe (see picture on next page). From the bast fibers of the stem of this herb linen cloth is made. Vegetable Oils. Some of the same plants which give fiber also produce oil. Cotton seed oil pressed from the seeds, linseed oil from the seeds of the flax plant, and coconut oil (the covering of the nut here producing the fiber) are examples. are harmful. For example, the poison ivy is extremely poisonous to touch. The poison ivy is a climbing plant which attaches itself to the trees or walls by means of tiny air roots which grow out from the stem. It is distinguished from its harmless climbing neighbor, the Virginia Creeper, by the fact that its leaves are notched in threes instead of fives. Every boy and girl should know poison ivy. Numerous other poisonous common plants are found, but one other deserves special notice because of its presence in vacant city lots. The Jim do the greatest damage are weeds. Those plants which provide best for their young are usually the most successful in life's race. Plants which combine with the ability to scatter many seeds over a wide territory the additional characteristics of rapid growth, resistance to dangers of extreme cold or heat, attacks of enemies, inedibility, and peculiar adaptations to cross-pollina tion or self-pollination, are usually spoken of as weeds. They flourish in the sterile soil of the roadside and in the fertile soil of the garden. By means of rapid growth they kill other plants of slower growth by usurping their territory. Slow-growing plants are thus actually exterminated. Many of our common weeds have been introduced from other countries and have, through their numerous adaptations, driven out other plants which stood in their way. Such is the Russian Thistle. A single plant of this kind will give rise to over 20,000 seeds. First introduced from Russia in 1873, it spread so rapidly that in twenty years it had appeared as a common weed over an area of some twenty-five thousand square miles. It is now one of the greatest pests in our Northwest. Hunter, Laboratory Problems in REFERENCE BOOKS ELEMENTARY Civic Biology. American Book Company. Toothaker, Commercial Raw Materials. Ginn and Company. U. S. Dept. of Agriculture, Farmers' Bulletin 86, Thirty Poisonous Plants of the United States, V. K. Chestnut. Bulletin 17. Two Hundred Weeds, How to Know Them and How to Kill Them, L. H. Dewey. ADVANCED Bailey, Cyclopedia of American Agriculture. The Macmillan Company. HUNTER, CIV. BI.—9 XI. PLANTS WITHOUT CHLOROPHYLL IN THEIR RELATION TO MAN Problems. (a) How molds and other saprophytic fungi do harm to man. (b) What yeasts do for mankind. (c) A study of bacteria with reference to (1) Conditions favorable and unfavorable to growth. (2) Their relations to mankind. (3) Some methods of fighting harmful bacteria and diseases caused by them. LABORATORY SUGGESTIONS Field work. - Presence of bracket fungi and chestnut canker. Demonstration. - Process of fermentation. Growing yeast cells. Drawing. Home experiment. Conditions favorable for growth of yeast. - Conditions favorable for growth of yeast in bread. Demonstration and experiment. - Where bacteria may be found. Demonstration. - Methods of growth of bacteria, pure cultures and colonies shown. Demonstration. - Foods preferred by bacteria. Demonstration. - Conditions favorable for growth of bacteria. Demonstration. - Conditions unfavorable for growth of bacteria. Demonstration by charts, diagrams, etc.- The relation of bacteria to disease in a large city. COLORLESS PLANTS ARE USEFUL AND HARMFUL TO MAN The Fungi. We have found that green plants on the whole are useful to mankind. But not all plants are green. Most of us are familiar with the edible mushroom sold in the markets or |