8 not for scientific or practical purposes, but PLANT PATHOLOGY Meyer, an extraordinary man who died at seems to have antedated the work of Meyer by It is the only botanical De All of the work on plant diseases and the breadth of knowledge along many lines of bot- CAPRA ipment and money and should do good rk. POLLINATION OF FLOWERS Another phase of the subject of economic cany is that of pollination. Progress was w. Geoffroy, who as early as 1711 made me observations on the nature of the style, said to have conducted some experiments th maize; however that may be he did make e of the work of Camerarius. Geoffroy conuded from various sources that fertilization as a kind of fermentation, but he was inined to accept a second view of Morland that e pollen grains contain the embryo which nd their way to the seed. We may also recall Le work of John Logan, at one time govnor of the colony of Pennsylvania, who onducted experiments on the fertilization of aize, in which he noted that cobs covered ith muslin did not produce seed, but seed as formed on cobs where pollen came in conact with the stigmas. Logan suggested that he wind carried the pollen. Gleditsch in a tudy of one of the palms (Chamarops umulis) strewed loose dried pollen on the tigmas of a female plant which produced seed which later was planted and germinated; a imple experiment but a convincing one to the -otanists of the time, who had never seen polination demonstrated before. Philip Miller n 1751 calls attention for the first time to the mportance of insects in the pollination of ulips. The first scientific experiments on hyprids were made by Koelreuter, who discovered the use of nectar and the importance of insects in the pollination of flowers. Koelreuter clearly set forth the facts that the mingling of two substances produced a seed. These general statements as set forth by him still hold true. He was a skillful experimenter in the hybridizing of plants. The work of Sprengel on the pollination of flowers is well known to the older botanists. His sharp discriminating observations on the relation of insects to flowers were little understood at the time. The full import of these problems were recognized by Charles Darwin, who in his masterly way showed the application of this in practical problems. Earlier Sir Andrew Knight had demonstrated "that no plant fertilizes itself through an unlimited number of generations." Dr. Gray put this in a much more terse way. A score of investigators like Hermann Mueller, Fritz Mueller, Delpino, Ludwig Axell, Hilderbrandt and in our country men like Gray, Trelease, Riley, Foerste, Beal and Robertson demonstrated the use of insects in pollination and the application of this fact to important agricultural crops. These fundamental facts are fully recognized to-day in the growing of apples, alfalfa, sweet clover, melons, squash and cucumbers. The orchardist recognizes the importance of bees in connection with the growing of apples, pears and plums. The farmer recognizes the importance of bees in the alfalfa and sweet clover fields, just as Charles Darwin recognizes that the bumble bee is important in the red clover pollination. In this connection, as an economic problem, I may call attention to the honey flow in flowers. It is true beekeeping is only one of our minor agricultural problems dependent entirely on the relative abundance of honey plants in a given region. There are a great many interesting physiological problems in connection with nectar secretion, as Kenoyer has shown. One wonders why alsike clover scarcely yields any nectar for bees in Iowa and yet in some regions of the country it is one of the best of nectar plants. There is seldom any nectar in buckwheat flowers after 10:00 A.M. in Iowa, and yet in sections of the United States the period of nectar flow is much longer. Is soil alone a factor or is moisture an important factor, or are the two factors combined? We have enormous expanses of waste land along our highways in the United States, why not combine the esthetic with the economic if we can find plants that are suited for such places that will yield good returns for the beekeeper. PLANT BREEDING I heard a practical fruit grower in Iowa say the other day when a new chance seedling apple was shown me that nearly all of the new good things in the fruit line are chances; that 10 is to say the new productions by Burbank, In the matter of fundamental study of these problems practical agriculture, horticulture and floriculture are indebted to the classic fundamental work of Hoffmeister and Strasburger. This work led up to and explains the physical basis of Mendelism discovered by Gregor Mendel, a work that is most important in the breeding of new types. We have had a host of botanical investigators who have enhanced our knowledge of plant breeding, linking it with practical work like Nilsson, Johannsen, Bateson, Correns, Shull, White, Webber and Emerson. Agriculture and horticulture are indebted to the epochmaking work of DeVries on mutation. His work has set a score of botanists to work on the pedigree culture work. I may mention Nilsson, Johannsen and Gates especially. Possibly the outstanding problem of the pomologist in states like Iowa and Minnesota is that of hardiness. In breeding experiments at the present time it is necessary to set the trees out and test them for a term of years, to see whether or not this climate is too severe. Bakke in some recent experiments has found that by ascertaining the depression of the freezing and the moisture content at a time when all the tissues are in an active state of growth, it is possible to obtain an idea of the comparative hardiness of different apple trees. These tests have been made upon trees in the nursery as well as upon trees in an orchard, 10 years old, with practically the same results. SEED STUDIES After a consideration of pollination the The first matter of seed is of importance. great work published is that of Gartner, "De fructibus Seminibus plantarum." Gartner was free from the bias of those who preceded him. We have a truly modern work by one whom we may regard as a modern man of science. He made a comparative study, correctly determined the relation of the endosperm to the cotyledon and named the embryo. We have had a long line of investigators on the subject of seeds. The practical application found expression in the work of Nobbe, Harz and others. We may recall the work of Nobbe in the testing of seeds at the small experiment station at Tharand, which was the beginning of the experiment stations such as we know them today. Nobbe did not merely do the mechanical part in connection with the testing of seed but inquired into real scientific problems in connection with specific gravity, and the vital ity of seeds under different conditions o storing. The germination of many seeds is of special concern to the agriculturist, be cause it is important to know under wha conditions a seed will germinate best to bring the largest returns. It is a matter also o some concern for the farmer to know whethe weeds' seeds have a varying period of vitalit when buried in the soil, whether for instanc the seeds of Hibiscus Trionum and Abutilo Theophrasti will come up in his fields after quarter or half a century when he practise rotation of crops. The vitality and structur of seeds has of course received much atten tion. I need only recall the classic work c DeCandolle who more than a century ag studied the prolonged vitality of seeds. Th data secured by DeCandolle is frequentl quoted in text-books of plant physiolog. Also much later work of Becquerel, Bea Ewart and Hanlein on delayed germination as well as the work of Crocker and his st dents like Shull, on the delayed germination seeds, like wild oats and other seeds of ec nomic importance. To Crocker we are in debted for an explanation of the delaye germination of such seeds as the cocklebu Knowing that there is a delay in some se the farmer is better able to follow a ration practise in the treatment of seeds. I am su that most of you are familiar with the wo of Schleiden and Vogel, Chalon, Malpig 66 aberlandt, Sempolwski, Beck, Moeller and esterle, Mattirolo and Buscalioni, Hanausek, arz, Junowicz and many others who were terested in a study of seeds of Leguminosa, articularly with reference to the light line. The writer more than a quarter of a century go brought the literature on this subject toether in his paper on the Comparative natomy of Seeds of Leguminosa." Comaratively little has been done since. Inensive studies on the seeds of such families s the Leguminosa. Convolvulaceæ, Cucurbiacer, Malvaceae, Tiliacea should be made beause in most of these families where the ight line occurs the seeds have a prolonged itality. The subject has more or less of a practical bearing. The problem as to the nature of the light line in these seeds has not been solved. A number of present-day botansts, like Martin, Harrington and others are aking up the problem. Present-day investigations with seeds are bringing many valuable practical results in commercial seed production, as in clovers. The seed control work by the establishing standards of purity is a practical problem. The work in determining the conditions of germination, experiments with light, electricity, heat, moisture and drying and studies of seed coat are also important. The important problem of rate of maturing of seed in storage is being worked out. Seedtesting laboratories, while they are obliged to answer the immediate pressing problems on the impurities of seeds and their germination are engaged in a study of the more fundamental problems of the viability of seeds. It has been the custom for the American Seed Analysts Association to send to its co-workers seeds to test for purity and vitality. With careful treatment, there is still the greatest variation in the results. Presumably, in part at least, the methods used by seed testers is not the same and, therefore, the result can not be uniform. We should bear in mind that the viability is a matter of climate and condition of storage of the seed. The fundamental problems of every one of the great staple agricultural crops, so far as vitality of seeds is concerned, has not been entirely solved and awaits solution by the investigator. The writer and Miss King, during the past few years, have continued investigations on germination of seeds of forest trees and shrubs. The results exhibit surprising irregularity and uncertainty in the germination of these seeds. Boerker, of Nebraska, has followed the same line of research. The work of Sir John Lubbock on Seeds and Seedlings and various papers of Tubeuf on seeds of forest trees, although purely morphological are always valuable for reference and bear in general upon forestry problems, of economic botany. GRASSES Botanists have long recognized the importance of grasses in our welfare. The prosperity of the United States outside of the rich natural resources of forestry, mines and water power is concerned with the economic production of cereals, cotton and livestock. Turning to some of the older works I recall the work of Sowerby and Parnell on grasses, Metzgar, "Die Gereidarten," Stebler and Schroeter, "Körnicke, Die Gebreidearten," and Hackel, "True Grasses." In our own country early works were Flint's "Grasses of Massachusetts," Klippart, "Grasses of Tennessee," Lapham, "Grasses of Wisconsin," Vasey, "Grasses of the United States," Lamson-Scribner, various papers published by the U. S. Department of Agriculture, Beal, "Grasses of North America," Hitchcock and Chase papers. These and other authors touching the economic problems of cereals, like Hunt, Carleton, Shear, Warburton and Ball have stimulated prduction but it would seem as though we have only scratched the surface so far as a study of the real problem of cereal production is concerned. It vitally concerns us as a nation to stimulate the production of cereals and forage crops because the ever-increasing population demands increased production. How can the botanists contribute more to the welfare of mankind than to study such problems as the physiology of the nutrition of the growing of wheat, maize, oats, barley and rice, or to make a study of pollination 12 SCIENCE a are under different climatic conditions, or the can WEEDS spores The subject of weeds is related to that of plant disease. It greatly interests the farmer and gardener. The farmers of the United States, at least in some sections, have endeavored to remove by legislation some of the injurious weeds, expecting, of course, that the law would be obeyed and the weeds would so We have described weeds and how Kesselback makes it clear that weeds suc sunflower use more than three times as m water per plant as corn. while water used |