Genome size varies dramatically across species, but despite an abundance of attention there is little agreement on the relative contributions of selective and neutral processes in governing this variation. The rate of sex can potentially play an important role in genome size evolution because of its effect on the efficacy of selection and transmission of transposable elements (TEs). Here, we us...

I n a study of the compatibilities of certain Nicotiana species, several crosses were reported which produce seeds unable to germinate. (MCCRAY 1932). Many others are recorded in the literature on this genus. Some of these seeds are parthenocarpic; others have embryos not able to develop. In still other cases the hybrid germinates but is unable to carry on further. All degrees of vigor have bee...

In an earlier paper (DAVIS 1918) there were published some observations on a selfed line of Oenothera brevistylis which had been carried for two generations through plants selected for greater variation in the direction of normal styles and stigmas. The line has now passed through five generations of selection, and not only has there been no improvement but the generations of later years have s...

This study was conducted to investigate the effects of foliar endophytic fungi and arbuscular mycorrhizal fungi (AMF) on plant community structure in experimental microcosms containing an assemblage of five species of plants (Oenothera odorata, Plantago asiatica, Trifolium repens, Isodon japonicas and Aster yomena). Leaves of Sasa borealis, Potentilla fragarioides, and Viola mandshurica were co...

ERTAIN peculiarities of the cross Oenothera franciscana Bartlett X OenoC them biennis L. led me to grow in recent years some large F1 families in one of which there appeared a tetraploid plant, the cytology and genetical behavior of which showed it to be an amphidiploid. This plant and its progeny will be the subject of this paper. The cross franciscanaxbiennis from parents out of long inbred l...

Earlier studies have considered the separate effects of temperature and gibberellic acid (GA3) on plants seeds. However, combined these factors parent their progeny received little attention. We investigated two regimes (24/20 °C 28/24 °C, 16 h light/ 8 dark) GA3 treatments (for weeks) reproductive yield plants, subsequent seed germinability, seedling traits four local populations evening primr...

ENOTHERA organensis is endemic to the Organ Mountains of 0 southern New Mexico where the entire population apparently consists of considerably less than one thousand individuak2 The morphology of the seeds indicates a relationship to members of the subgenus Oenothera (sometimes called Onagra), but the growth habit and ovule placentation resemble types belonging to the subgenus Raimannia (the Eu...

The timing of reproduction is a key determinant of Ž tness. Here, we develop parameterized integral projection models of size-related  owering for the monocarpic perennial Oenothera glazioviana and use these to predict the evolutionarily stable strategy (ESS) for  owering. For the most part there is excellent agreement between the model predictions and the results of quantitative Ž eld studie...

1 The effects of floral resources of several important non-crop host plants of Lygus lineolaris on the longevity of Anaphes iole , one of its natural enemies, was studied. 2 Median longevity of A. iole wasps provisioned with floral resources ( Erigeron annuus , Oenothera speciosa , Lamium amplexicaule , and Capsella bursapastoris ) was in the range 1.27 – 3.24 days, and did not differ from wasp...