individuals favoring their development, but the neglected nursery is literally a pest house of plant diseases. The Pennsylvania Chestnut Tree Blight Commission has records of spot infections of blight that were traced to the planting of nursery stock that was diseased at the time of shipment. The diseases of nursery stock that are accompanied by easily recognized symptoms, may easily be guarded against by rigid inspection of all stock offered for shipment, and fumigation is a reasonable safeguard against the spread of many insect pests, but unfortunately some of the most serious diseases can be carried by stock which shows no indication whatever of its presence. One of the most striking examples of this is to be found. in the case of the seedlings of white pine affected with the so-called blister rust. The fungus causing this trouble has a period of incubation in the bark of nearly a year before it causes the characteristic hypertrophies, and for this reason inspection at the time of importation is but an imperfect insurance against its introduction. In such extreme cases the quarantine of infected regions and the restrictions of shipment of stock that might carry the disease is entirely justifiable. Diseases like the black-knot, peach leaf curl, orange rust of raspberries and blackberries, and many others that produce a perennial mycelium in the host may easily be transported by infected nursery stock, while there are many opportunities for the transport of resistant spores on the surface of florists' greenhouse stock or field-grown plants. Besides this, incipient infections of various fungi may be present in either herbaceous or woody plants, and entirely escape detection at the time of shipment. The transport of various commodities such as hay, grain, packing material, fruits, vegetables, wood, lumber and any crude plant products must play a part in the spread of plant disease. With our diversified trade relations with foreign countries and the extensive trans-continental shipments of plant products from west to east and from south to north, opportunities for the transport of plant diseases over wide ranges of territory are greater than ever before in entire progress of our agriculture. Zoology Building, Univ. of Pa. Philadelphia, Pa. 1. BULLER, A. H. R. LITERATURE CITED Research on fungi. 1-287, 1909. Longmans, Green & Co. 2. FRANK, A. B. Die Krankheiten der Pflanzen. 3. WHETZEL, H. H. 2:380-382. 1896. Berichte der Some diseases of beans. Bull. Cornell Agr. Exp. Sta. 239:198-214. 1906. Bean anthracnose. Bull. Cornell Agr. Exp. Sta. 255:217222. 1908. 4. VAN HOOK, J. M. Blight and powdery mildew of peas. Bull. Ohio Agr. Exp. Sta. 173:231-249. 1906. 5. BARRE, H. W. Report of the botanist. Report S. Carolina Agr. Exp. Sta. 1910: 23-26. 6. MANNS, T. F. Two recent important cabbage diseases of Ohio. Bull. Ohio Agr. 7. CHAPMAN, G. H. Notes on the occurrence of fungous spores on onion seed. Report 8. HEALD, F. D. Bunt or stinking smut of wheat. Press. Bull. Nebr. Agr. Exp. Sta. 28:1-8. 1908. 9. BOLLEY, H. L. IO. The use of the centrifuge in diagnosing plant diseases. Proc. Soc. STÖRMER, K. and EICHINGER, A. Frühling's Landw, Ztg. 59:393-413. 1910. II. HALSTED, B. D. and FAIRCHILD, D. G. Sweet potato black-rot. Journ. Myc. 7:1-11. 1891. 12. COONS, G. H. Some investigations of the cedar rust fungus. Ann. Report Nebr. 13. WOLF, F. A. The prevalence of certain parasitic and saprophytic fungi in orchards as determined by plate cultures. Plant World 13:164-172. 190-202, 1910. 14. FULTON, H. R. Recent notes on the chestnut bark disease. Penn. Chest. Blight 15. ANDERSON, P. J., Elza, W. H. and BABCOCK, D. C. Field studies on the dissemination and growth of the chestnut blight fungus. Bull. Penns. Chestnut Blight Commission. 3:1-, 1913. 16. LLOYD, F. E. and RIDGWAY, C. S. Bull. Ala. Agr. Dept. 39:1-19. 1911. 17. BURRILL, J. T. and BARRETT, T. J. The ear rots of corn. Bull. Illinois Agr. Exp. Sta. 133:65-109. 1908. 18. SMITH, R. E. The brown rot of the lemon. Bull. Cal. Agr. Exp. Sta. 190:1-70. 1907. 19. ROGERS, C. S. The late blight of celery. Bull. Cal. Agr. Exp. Sta. 208:83-115. 20. FULTON, T. W. The dispersal of the spores of fungi by the agency of insects with special reference to the Phalloidei. Ann. Bot. 3:1899-90. 21. WEBBER, H. J. Sooty mold of the orange and its treatment. Bull. Div. Veg. Phys. and Path. U. S. Dept. of Agr. 13:1-34. 1897. 22. WAITE, M. B. Cause and prevention of pear blight. Yearbook, U. S. Dept. Agr. 1895:295-300. 23. HEALD, F. D. The bud rot of carnations. Bull. Nebr. Agr. Exp. Sta. 103:1-24. 1908. 24. MURRILL, W. A. A serious chestnut disease. 25. MASSEE, GEO. Jour. N. Y. Bot. Garden. 7:143-153. Diseases of cultivated plants and trees. 1-602. 1910. Macmillan & Co. 26. JOHNSTON, J. R. The history and cause of the cocoanut bud rot. Bull. Bur. Pl. Ind. 228:1-175. 27. VOGLINO, P. 1912. Richerce intorno all' azione delle lumache e dei rospi nello sviluppo di Agaricini. Nuovo Giornale Botanico 27:181-185. 1895. 28. HAYS, W. M. Rules and regulations for carrying out the plant quarantine act. U. 29. STEVENS, F. L. A serious lettuce disease. Bull. N. C. Agr. Exp. Sta. 217:1-21. 1911. 30. Gussow, H. T. A serious potato disease occurring in Newfoundland. 31. SPAULDING, PERLEY. Bull. Can. The blister rust of the white pine. Bull. Bur. of Pl. Ind. 206:1-88. 1911. THE PERIODICITY OF ALGAE IN ILLINOIS BY EDGAR NELSON TRANSEAU The following notes on the periodicity of algal occurrence and reproduction are based on a study of collections made at intervals, at more than a hundred stations in East-central Illinois. They cover the period from January, 1908, to January, 1913. About half of these stations are in the vicinity of Charleston. These have been visited at frequent intervals, while those at a distance have been examined at critical times of the year as suggested by conditions at Charleston. All collections have been preserved in a solution, a liter of which contains 100 cc. formalin, 300 cc. alcohol, and 600 cc. of water. Each collection is labeled and numbered in the field and as soon as convenient a 4 by 6 inch index card is labeled and numbered to correspond. On this is kept (1) a record of the weather conditions, water conditions, temperatures, relative abundance of algae in general, and whether floating or attached, etc.; (2) an analysis of the collection made in the laboratory, showing all algae present as far as identifiable. In the case of many only the genus can be given, together with measurements that might aid in determining them from later collections containing the same forms in a fruiting condition. In summarizing the work it is possible then to go back to cards or to the collections at any time and correct any errors or get any further data desired. The waters of Eastern Illinois are rich in dissolved mineral matters derived from the prairie soils. For example, the water of the Embarras river near Charleston contains on the average .14042g. of soluble matter per liter. It is consequently not surprising that the algal flora should be large and varied. Its extent may be roughly indicated by the fact that the collections contain more than fortyfive species of Oedogonium, and the genus Spirogyra is represented by at least thirty-five species and varieties. These numbers are considerably more than have been reported from Massachusetts |