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Articles 13441 - 13467 of 13467

Full-Text Articles in Plant Biology

Bulletin No 69 - The Poison Plants Of Western Australia, D. A. Herbert Jan 1921

Bulletin No 69 - The Poison Plants Of Western Australia, D. A. Herbert

Bulletins 1 - 2999

Up to the present no publication dealing with the whole of the known i)01S0fl plaits of Western Australia has been written. This Bulletin contains the collected accounts of various authors and correspondents which have been published at different times and contains a large amount of original information gathered both from field experience and from laboratory experiments. The work is not complete. A number of plants from distant districts have not been obtainable or obtainable only in amounts insufficient for exhaustive tests. These plants are comparatively few, however, and in Section 13 of this publication those which are suspected, but against …


The Relative Frequency Of Crossing Over In Microspore And In Megaspore Development In Maize, R. A. Emerson, C. B. Hutchison Jan 1921

The Relative Frequency Of Crossing Over In Microspore And In Megaspore Development In Maize, R. A. Emerson, C. B. Hutchison

Department of Agronomy and Horticulture: Faculty Publications

One of the early developments in the study of linkage in Drosophila was the discovery that the phenomenon of crossing over is confined to the female sex (Morgan 1912). The fact that no crossing over occurs in the male Drosophila holds true not only for sex-linked genes but for factors in the autosomes as well and is so well established that it affords a most convenient method of determining to which of the different linkage groups a new factor belongs.

The same phenomenon, but with the sexes reversed, obtains in the silkworm moth. Tanaka (1914, 1915) has found from back-cross …


Heritable Characters Of Maize: Ix. Crinkly Leaf, R. A. Emerson Jan 1921

Heritable Characters Of Maize: Ix. Crinkly Leaf, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

In 1910 a strain of dent corn obtained at the National Corn Exposition held at Omaha was crossed with a strain of flint corn obtained from the Department of Agronomy of the University of Nebraska. The F1 plants of this cross were normal and no abnormalities had been observed in the parent strains. But since the latter had not been subjected to self-pollination, there is no assurance that one or other of them did not have in it the character to be described here. In the F2 generation of this cross there occurred a tpe of plant that …


Bulletin No 81 - The Improvement Of Pastures With Notes On The Pasture Trefoils In Western Australia, E. A. Mann, D. A. Herbert Jan 1920

Bulletin No 81 - The Improvement Of Pastures With Notes On The Pasture Trefoils In Western Australia, E. A. Mann, D. A. Herbert

Bulletins 1 - 2999

Agriculture can be roughly divided for practical purposes into two large divisions, those of animal husbandry and vegetable husbandry. It is with the former that this pamphlet is chiefly concerned and its object is to contribute, it possible, in some small measure towards the problem of how to increase time stock carrying capacity of our natural pasture lands. it is unnecessary to dwell upon the importance of this question, especially in relation to the remarkable developments which are taking place in time wool-growing industry in the Southern and more coastal areas of Western Australia.


Bulletin No 80 - Cultivation Of Sugar Beet, Percy G. Wicken Jan 1920

Bulletin No 80 - Cultivation Of Sugar Beet, Percy G. Wicken

Bulletins 1 - 2999

The beet belongs to the Chenopodiaceae or Salsolaceae, an order of plants which include among them many of the native saltbushes. The sugar beet (Beta vuigaris crassa) is supposed to have been developed from the wild beet (Beta vulgaris maritima), which is indigenous to the countries along the coast of Southern Europe. it is a biennial plant—that is, of two years' duration. The first year it produces a full-sized root, the second year it produces its seeds, and then dies off. Sometimes a few plants Produce seed the first year, but this is only on account of the seed being …


Heritable Characters Of Maize Ii.-Pistillate Flowered Maize Plants, R. A. Emerson Jan 1920

Heritable Characters Of Maize Ii.-Pistillate Flowered Maize Plants, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

In the "freak"

class at the Annual

Corn Show held at Lincoln, Nebraska,

in the winter of 1913-14,

there was exhibited a corn tassel

with a heavy setting of seeds. A few

seeds are not infrequently found in the

staminate inflorescence of maize, particularly

in pod com, and tillers of various

corn varieties often end in ears instead

of in tassels or have tassels, the central

spikes of which are ear like. The freak

exhibited at the com show, however,

was a large. much branched affair.

wholly tassel-like in form except for the

fact that it bore a heavy crop …


Relation Of Size Of Seed And Sprout Value To The Yield Of Small Grain Crops, T. A. Kiesselbach, C. A. Helm Dec 1917

Relation Of Size Of Seed And Sprout Value To The Yield Of Small Grain Crops, T. A. Kiesselbach, C. A. Helm

Nebraska Agricultural Experiment Station: Historical Research Bulletins

A superior yielding power has frequently been attributed to the extra large seed. Since the seeds of any given crop commonly differ markedly in size, it is of importance from the standpoint of crop production to know the extent to which this difference in size may affect the yield of the crop produced. The following experiments have been conducted for the purpose of contributing further to the information upon this subject.


Genetical Studies Of Variegated Pericarp In Maize, R. A. Emerson Jan 1917

Genetical Studies Of Variegated Pericarp In Maize, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

Two years ago there were presented some results of a study of the inheritance of self pattern in the pericarp of maize seeds, occurring as a sporophytic2 variation in variegated ears (EMERSON1 914). Further results, in entire accord with those previously reported, have now been obtained. In addition, data bearing upon new phases of the problem are also available.

The chief results reported in the earlier paper were the following: ( I ) The more nearly self-colored the pericarp of any seed of a variegated ear, the more likely is the progeny of that seed to produce a self-colored ear …


Transpiration As A Factor In Crop Production, T. A. Kiesselbach Jun 1916

Transpiration As A Factor In Crop Production, T. A. Kiesselbach

Nebraska Agricultural Experiment Station: Historical Research Bulletins

The object of experiments reported in this bulletin has been to determine principles according to which water is used by crops. In many agricultural districts, water is frequently a seriously limiting factor in crop production. It has been thought that some means might be devised through a correct understanding of the principles involved, whereby economy in the use of water in farm practice could be increased. In this effort there are two chief points of attack, namely, (1) adjusting the external factors to the needs of the plant, and (2) selecting plants adapted to the conditions.


The Inheritance Of A Recurring Somatic Variation In Variegated Ears Of Maize, R. A. Emerson Jan 1914

The Inheritance Of A Recurring Somatic Variation In Variegated Ears Of Maize, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

The inheritance of variegation has special interest and importance in genetics. It is with forms of variegation that the only two certainly known cases of non-Mendelian inheritance have had to do. I refer to Baur's experiments with Pelargonium, in which crosses of green-leaved and white-leaved forms exhibited somatic segregations in F1 that bred true in later generations, and to Correns 's work with Mirabilis, which showed green and white leaf color, to be inherited through the mother only. De Vries's con- ception of "ever-sporting" varieties was apparently founded largely upon the behavior of variegated flowers in pedigree …


Multiple Factors Vs. "Golden Mean" In Size Inheritance, R. A. Emerson Jan 1914

Multiple Factors Vs. "Golden Mean" In Size Inheritance, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

Groth's preliminary note on the "golden mean" in the inheritance of sizes in SCIENCE of April 17, 1914, pp. 581-584, deserves the attention of geneticists. Its publication is of such recent date that I need only call attention to one or two points that seem to me of particular moment.

In brief, Groth's hypothesis is that the mode

of inheritance in Fl not only of surfaces and

volumes, but also of linear dimensions is to be

expressed by √ab rather than by a + b /2

where a and b are parent sizes. The hypothesis

is based upon …


Shorter Articles And Discussion Simplified Mendelian Formulae, R. A. Emerson Jan 1913

Shorter Articles And Discussion Simplified Mendelian Formulae, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

I was somewhat surprised by 'Morgan's and Castle's suggestions for a simplification of Mendelian formulae. My surprise was not occasioned so much by the forms these suggestions took as by the fact that any pronounced changes were deemed necessary. I had not only employed the usual formula in my own work but had found no difficulty worth mentioning in understanding the formula used by most other workers in Mendelian fields. My experience with students in elementary courses in genetics had not prepared me for the idea that such formula were particularly difficult. Nevertheless I believe in simplifying the formulae if …


The Possible Origin Of Mutations In Somatic Cells, R. A. Emerson Jan 1913

The Possible Origin Of Mutations In Somatic Cells, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

That mutations are accompanied by some change in the germ-plasm is, I take it, indisputable. Have we, however, any reason to suppose that the change takes place within the germ cells? I am not sure, as a matter of fact, that genetists in general regard the gametes as the place of origin of mutations. It is true, however, that experiments in the artificial production of mutations in plants have been limited largely to treatments of the ovaries from about the time of the reduction division to about the time of fertilization. This suggests a belief on the part of investigators …


Shorter Articles And Reports: The Simultaneous Modification Of Distinct Mendelian Factors, R. A. Emerson Jan 1913

Shorter Articles And Reports: The Simultaneous Modification Of Distinct Mendelian Factors, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

In another paper on the inheritance of a recurring somatic variation in variegated ears of maize, it was shown that the amount of red color developed in the pericarp of variegated seeds bears a definite relation to the development of color in the progeny of such seeds. The relation is such that the more color there is in the pericarp of the seeds planted the more likely are they to produce plants with wholly self-red ears and correspondingly the less likely to produce plants with variegated ears. Self-red ears thus produced behave just as if they were hybrids between self-red …


Botanical Specimens (Herbarium) By Alice Ford, 1912, Alice Ford Jan 1912

Botanical Specimens (Herbarium) By Alice Ford, 1912, Alice Ford

Botanical Specimen Books

This botanical specimen book (herbarium) was collected and curated by Sara Alice Ford in spring 1912 for a Botany I course taught by John M. Holzinger at the Winona Normal School in Winona, Minnesota. These plants were collected in the Witoka area. Sara Alice Ford Einhorn (1983-1992) grew up in the Witoka Area and attended Winona Normal School, graduating in 1912. She taught in the area rural schools (Boynton and Ridgeway) before marrying Clifford Einhorn. They lived in North Minneapolis before moving back to Winona in the 1940s.

Daughter of Kathryn Jeanette Einhorn Anderson who graduated from Winona Teachers' College …


The Unexpected Occurrence Of Aleurone Colors In F2 Of A Cross Between Non-Colored Varieties Of Maize, R. A. Emerson Jan 1912

The Unexpected Occurrence Of Aleurone Colors In F2 Of A Cross Between Non-Colored Varieties Of Maize, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

Before the Mendelian methods of analysis became available, considerable wonder would doubtless have been excited by the "mysterious" appearance in F2 of one colored grain-purple or red-to every five or six white ones in case of a maize cross, both parents and F, of which had only white grains. An occurrence of this sort has recently been noted in one of my maize cultures and the F2 numbers are explained here as a trihybrid or tetrahybrid ratio. The crosses in question were made primarily for a study of size inheritance and fairly large numbers have been grown. The varieties …


A Consideration Of The Physiology And Life History Of A Parasitic Botrytis On Pepper And Lettuce, George L. Peltier Jan 1912

A Consideration Of The Physiology And Life History Of A Parasitic Botrytis On Pepper And Lettuce, George L. Peltier

Department of Plant Pathology: Faculty Publications

During the autumn of 1911, while gathering the peppers (Capsicum) in the vegetable plat of the Missouri Botanical Garden, the writer observed a fungus which was appearing as a parasite on the fruits. The peduncles were covered with a dark brown mass of conidia and mycelium, which so weakened the tissues that the fruit soon fell to the ground. On opening the peppers a number of large, flat, crust-like sclerotia, 1 cm. long and .5 cm. wide, were found to fill the interior. In most cases the seeds were also covered with the crust-like masses. The conidial stage …


Discussion And Correspondence Coupling Vs. Random Segregation, R. A. Emerson Jan 1911

Discussion And Correspondence Coupling Vs. Random Segregation, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

To the editor of science: The suggestion offered by Morgan, in SCIENCE of September 22, to account for the coupling and repulsion of factors for various characters in inheritance in such forms as Abraxas, Drosophila, fowls, sweet peas, etc., incites this note.

Briefly Morgan's hypothesis is (1) that the materials representing factors that couple are "near together in a linear series" in the chromosomes; (2) that, when pairs of parental chromosomes conjugate, "like regions stand opposed "; (3) that "homologous chromosomes twist around each other," but that the separation of chromosomes is in a single "plane"; (4) that, thereby the …


The Inheritance Of Sizes And Shapes In Plants, R. A. Emerson Jan 1910

The Inheritance Of Sizes And Shapes In Plants, R. A. Emerson

Department of Agronomy and Horticulture: Faculty Publications

Some years ago Lock reported a cross of a tall race of maize with a shorter race which produced an intermediate height in F1 and exhibited no segregation in F2 when crossed back with one of the parents. Castle's results with rabbits are very similar to those of Lock with maize. Castle summarizes his results in part as follows:

A cross between rabbits differing in ear-length produces offspring with ears of intermediate length, varying about the mean of the parental ear-lengths. . . . A study of the offspring of the primary cross-breds shows the blend of the …


The Relation Of Leaf Structure To Physical Factors, Edith Schwartz Clements Jan 1905

The Relation Of Leaf Structure To Physical Factors, Edith Schwartz Clements

School of Biological Sciences: Faculty Publications

The leaf, as the seat of important physiological functions of the plant, and because of its modification by external factors, has long been a fruitful subject for investigation. As a rule, however, investigators have confined themselves solely to the histology and morphology of the leaf, independent of its relations to physical factors. Where the latter have been considered at all, it has been in a more or less general way, or undue importance has been assigned to one or another of the physical factors, and others have been ignored entirely. In no case have they been carefully measured. The aim …


Botanical Specimens (Herbarium) By Helen J. Monahan, 1899, Helen J. Monahan Jan 1899

Botanical Specimens (Herbarium) By Helen J. Monahan, 1899, Helen J. Monahan

Botanical Specimen Books

This botanical specimen book was collected and curated by Helen J. Monahan in 1899 for a Botany course taught by John M. Holzinger at the Winona Normal School in Winona, Minnesota. Helen Josephine (Monahan) Rowekamp (1885-1967) was born in Witoka, Minnesota. She attended the Winona Normal School. In 1916 Helen (Monahan) Rowekamp married Julius Rowekamp and they farmed in the Lewiston area until 1947 when they moved to Winona. Mrs. Rowekamp's death was announced in The Winona Daily News on Sunday, March 05, 1967.


Observations Of The Adaptation Of The Leaves Of Kalmia Latifolia To Environment, Grace Ellen Wilson Jan 1898

Observations Of The Adaptation Of The Leaves Of Kalmia Latifolia To Environment, Grace Ellen Wilson

Student and Lippitt Prize Essays

Samples taken from the plant for observation are from two different locations (high dry land with full sun/low moisture and a swamp) and show that the leaves of the plant flourish more in sunlight than in dark, swamp areas.


Descriptions Of Iowa Uromyces, J. C. Arthur Jan 1886

Descriptions Of Iowa Uromyces, J. C. Arthur

Journal of the Minnesota Academy of Science

No abstract provided.


The Pinetum Britannicum, Edward Ravenscroft Jan 1884

The Pinetum Britannicum, Edward Ravenscroft

Archives & Reprint Series (imprint)

The Pinetum Britannicum: A Descriptive Account of Hardy Coniferous Trees Cultivated in Great Britain was authored by Edward James Ravenscroft (1816-1890) during the time period of 1863 through 1884.

This first edition Pinetum Brittanicum is regarded as an important British study of pines. Edward James Ravenscroft’s exquisitely detailed illustrations exemplify the widely embraced enthusiasm for the art and science of capturing and classifying conifers during the 19th-century. Ravenscroft was a master in the field of natural history illustration, which is often called “art in the service of science.”


The Asparagus For Histological Study, Charles E. Bessey Nov 1881

The Asparagus For Histological Study, Charles E. Bessey

Papers in Systematics and Biological Diversity

I have for several years been wanting a good Monocotyledon for histological study in the botanical laboratory, one which should be for its sub class what the pumpkin is for the dicotyledons. The indian corn, which is commonly used, is too difficult, and too greatly specialized a type, exhibiting as it does the peculiar nodal structure of the stem of the Grarninex, rather than the structure of the stem of monocotyledons in general. A good representative stem. and one which can be obtained everywhere in good condition, from early spring until the end of the season, is the asparagus. …


The Supposed Dimorphism Of Lithospermum Longiflorum, Charles E. Bessey May 1880

The Supposed Dimorphism Of Lithospermum Longiflorum, Charles E. Bessey

Papers in Systematics and Biological Diversity

The plant under consideration is a common herbaceous perennial of the prairies and great plains of North America. In the latter part of April and during the month of May it produces flowers with bright yellow salver-shaped (hypocraterimorphous) corollas, whose tubes are about thirty mm. (one and one-fifth inch) long, and from two to three mm. in diameter. About the first of June, in central Iowa, these large flowers suddenly disappear, and from this time forward until the autumn frosts, they produce only small cleistogamous flowers. The corolla lobes of the latter cohere somewhat, and remain closed, and …


Sensitive Stamens In Portulaca, Charles E. Bessey Jul 1873

Sensitive Stamens In Portulaca, Charles E. Bessey

Papers in Systematics and Biological Diversity

Two years ago my attention was first called to the sensitiveness of the stamens of Portulaca grandiflora, by observing a peculiar motion in them, while a small wild bee was engaged in gathering honey, and perhaps pollen, from the flowers. Upon trial I found that I could, by touching the stamens, make them move through quite considerable arcs of circles. I pursued the investigation somewhat farther at the time, but on account of a pressure of work was compelled to drop it. Last year I again made some examinations which confirmed my previous observations, but declined calling special attention …