摘要:

KATO, M., 1990.Ophioglossaceae: a hypothetical archetype for the angiosperm carpel. In the light of a recently proposed phylogenetic position of Ophioglossaceae as living progymnosperms, a new archetype model for the angiosperm carpel is proposed. The three‐dimensional construction of ophioglossoid fertile leaves with epiphyllous sporophores may be comparable to angiosperm carpels with adaxial ovules. The orientation of erect sporangia on young sporophores dorsiventrally facing the trophophores resembles that of anatropous ovuleS. Glossopterid fructifications may be interpreted as having the same construction as ophioglossoid leaveS. In the present hypothesis, the adaxial position of the ovules arose prior to the evolutionary process leading from gymnospermy to angiospermy. Previous hypotheses involving origins fromCaytoniaandGlossopterisare criticize

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1990.tb01883.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

In this treatment, the generaCoincya(synonym:Hutera) andRhynchosinapisare regarded as one genus under the nameCoincyawhich has nomenclatural priority. This study is based on data from morphology, population studies, cytology, ecology and reproductive biology reinforced by breeding experiments.Coincyais a west European genus comprising 14 taxa (including six species, five subspecies and three varieties).Eight new combinations are proposed and two species are excluded;R.nivalisis referable to the genusBrassicaandR. Leplocarpais probably referable toErucastrum.The chromosome number is either 2n= 24 or 2n= 48, which confirmed previous counts;C. Transtaganahas not been counted. Breeding experiments were carried out withC. Longirostra, C.rupestris, C.monensissubsp.monensis, diploid and tetraploid races of subsp.recurvatavar.recurvata, var.johnslonii, var.setigera, var.granatensis, subsp.hispidaand subsp.puberula.All taxa tested are outbreeding with a genetic self‐incompatibility mechanism and are cross‐compatible, suggesting that there has been no cytological differentiation between the diploid species in this study. The tetraploids formed semi‐sterile triploids when crossed with diploids and although the chromosomes only formed bivalents and trivalents at meiosis it was postulated that the tetraploid was an autotetraploid of polytopic origin.The evolution and differentiation of the genus and species are disc

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1990.tb01884.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY