Life Sciences Commons^™

Anatomy Of The Adults Of Loxagrotis Albicosta, C.Y. Oseto, T.J. Helms

Papers from the University Studies series (University of Nebraska)

LEPIDOPTERA are divided into the major suborders Monotrysia and Ditrysia (Borner, 1939). The vast majority of Lepidoptera belong to the Ditrysia. The Noctuidae, which is the largest family in the order, is probably the most destructive (Metcalf, et aI., 1962). It includes Loxagrotis albicosta (Smith), the western bean cutworm, originally a pest of field beans, which has become a relatively serious pest of corn in southwestern and central Nebraska (Hagen and Roselle, 1972). Adults emerge from early July to late August, and eggs, which are deposited on the upper sides of corn leaves, hatch in approximately I week. The newly …

The Genus Carduus L. In Nebraska, Marian Jane Fuller

Papers from the University Studies series (University of Nebraska)

The genus Carduus L., a member of the Compositae, consists of approximately 120 species native to Europe (Arenes, 1949; Mulligan and Frankton, 1954). Of these, C. acanthoides L., C. crispus L. and C. nutans L., have been introduced to North America, but only C. acanthoides and C. nutans have been reported in Nebraska.

A general description of the Nebraska members of this genus is as follows: annuals or biennials; herbaceous stems spiny winged; leaves lobed with spiny margins; heads solitary or clustered at end of branches; phyllaries imbricated, spine-tipped in many rows; florets tubular, perfect, usually purple, rarely white; cypsela …

Ecological Study Of The Weed Population Of Eastern Nebraska, Elva L. Norris

Papers from the University Studies series (University of Nebraska)

EXACT knowledge of the relations existing between weeds and cultivated crops is very limited. This is true also of the amount of viable weed seed present in arable soil. Impressions and observations have been recorded, but very few quantitative investigations have been made. The numerous circulars and bulletins about weeds, issued by many experiment stations, deal mostly with descriptions of species and methods of weed control. The present research was undertaken primarily to determine the relationship which exists between weeds and cultivated crops, but also to obtain an estimation of the number of viable weed seeds present in the soil. …

Size And Structure Of Leaves Of Cereals In Relation To Climate, William Edward Bruner, John E. Weaver

Papers from the University Studies series (University of Nebraska)

Although a very large amount of work has been done on the variation in form, size, and anatomical structure of native plants grown under different conditions, relatively little attention has been given to similar studies of crop plants. As far as we are able to ascertain, no investigations have been made of variation in the leaves of cereal crops grown under widely different, measured environments.

During the past few years (1920-23), in connection with studies on the development and activities of the roots of crop plants (Weaver, Jean, and Crist, 1922), plant production as a measure of environment (Weaver, 1924), …

Some Field Instruments And Their Applications, G. W. Goldsmith

Papers from the University Studies series (University of Nebraska)

Physiology and ecology depend for their constructive development largely upon the applications of physico-chemical concepts to living organisms and their environment, to their life processes, reactions, and interrelations. A concept is valuable biologically in so far as it can be applied and used as a tool for better understanding of the phenomena related to life. Ecology, as the study of the relations between organisms and their environment and of the interrelations of organisms, depends primarily upon the findings of physiology (Clements, 1905). But to apply physicochemical concepts and hence make them of value to the physiologist or ecologist commonly requires …

A Study Of The Vegetation Of Southeastern Washington And Adjacent Idaho, J. E. Weaver

Papers from the University Studies series (University of Nebraska)

Noone at all botanically inclined can travel through southeastern Washington without being impressed with the marked changes which a distance of only a few miles may show in the vegetation. Traveling eastward from a point fifty miles west of the Idaho state line, one passes from a region of scab-land sagebrush through one of rolling hills covered with bunch-grasses. Upon steadily ascending the great Columbia Plateau, the 'bunchgrasses give way to well developed prairies, and these in turn, near the Idaho line, to forests of yellow pine, Douglas fir, white fir, tamarack, and cedar. Or starting from Spokane in the …

Ecological Investigations Upon The Germination And Early Growth Of Forest Trees, Richard H. Boerker

Papers from the University Studies series (University of Nebraska)

Briefly stated the purpose of the present investigation is to inquire into the effect of the more important habitat and seed factors upon the germination and early development of certain American forest trees in control cultures in the greenhouse for the purpose of obtaining data that may be used in the ~ilvicultural management of these species.

Prefatory Note 1 / Preliminary Considerations 7 / Historical 7 / Classification and Resume of Habitat Factors 11 / The Germination Process 15 / Method of Attacking Problem at Hand 19/ Methods and Apparatus Used 2 1/ The Control of Habitat Factors 24 / …

The Effect Of Climate And Soil Upon Agriculture, Russell R. Spafford

Papers from the University Studies series (University of Nebraska)

Field studies in farm management are at present almost whclly confined to measu ring the profitableness of a farm business and analyzing the effect of those factors which fall largely within the control of the farm operator. While factors beyond individual control have always been recognized in field work, very little attempt has thus far 'been made to measure their influence upon farming; It is true that with present weather, soil, botanical, census, and farm management data only preliminary measurements can be made, but nevertheless such measurements do much toward correlating what at present are disconnected facts in agricultural science. …

On A New Subspecies Of Porcupine From Nebraska, Myron H. Swenk

Papers from the University Studies series (University of Nebraska)

Publication NO.2 of the Nebraska State Biological Survey.

Nebraska porcupines all belong to the yellow-haired species (Erethizon epixanthum) , and these animals have never been abundant in the state. Formerly, however, they were much more numerous than today, and enjoyed a more extended range in the state than they do at the present time. Up to about 1885 these animals occurred across the northern portion of Nebraska east at least to Pierce and Madison counties, there being records of four specimens secured along the small streams tributary to the Elkhorn river in these two counties between 1870 and 1885. Also, …

Histological Studies In The Artemisia Formation, Raymond John Pool

Papers from the University Studies series (University of Nebraska)

Many investigators have written on the subject of leaf histology and morphology in general, and a few have, in addition, touched upon the physiological significance of structures found during the progress of the study. Among these writers are Haberlandt, Pick, Stahl, Bonnier, Wagner, Hesselmann, and Clements. Most of the work, however, has been purely histological or morphological with little or no reference to environic forces. But in these later days of the development of the new ecology those forces or factors which have been potent in the evolution of plants and which are moulding plants today have come under careful …

The Sphegoidea Of Nebraska, Harry Scott Smith

Papers from the University Studies series (University of Nebraska)

The following paper is the result of a study pursued by the writer at odd intervals during the past two years, and is based on the material contained in the collection of the University of Nebraska. Although the list is a fairly large one for a single state, nothing like systematic collecting has been done on the group, and it is expected that a great many additional species will be found in the near future. The only portion of the state that has been at all closely collected is Sioux county, where, during the past ten years, several zoological expeditions …

On The Movements Of Petals, Esther Pearl Hensel

Papers from the University Studies series (University of Nebraska)

The following paper has to do with an investigation of the physical causes· which bring about opening and closing movements, periodic or otherwise, of certain flowers. With that end in view, seven different species of flowering plants have been experimented upon directly, a much larger number being simply observed with respect to the nature, time, etc., of their anthotropic movements. Movement consists in the corolla taking upon itself either the open or closed position for certain periods of the day or night; for example, the morning glory (Ipomoea purpurea) opens early in the morning (from 4:00 to 5 …

Plant Migration Studies: Forest Trees, Charles E. Bessey

Papers from the University Studies series (University of Nebraska)

It is a familiar fact that new species appear from time to time among the native plants of a region. Such newcomers turn out on examination to be new only in the sense that they have not previously lived in the region, and in every instance these new plants are found to have come from other regions where they had existed for a longer or shorter period of time. In some cases the · new species remain for a time and then disappear, or at least become inconspicuous, but more commonly they crowd in among the former plants and become …