摘要:

A taxometric analysis of 153 colonies of the agamospermousLimonium binervosumaggregate in the British Isles has revealed an ordered hierarchy of variation. A taxonomic treatment of the group describes five new species, redefines four others and describes other infraspecific variants as subspecies or varieties. Each species is morphologically distinct and has a defined geographic range. There are four widespread and morphologically variable species and five geographically restricted species (four monotypic).Limonium recurvum, previously described as a microspecies endemic to a small area of the Dorset Coast, has been widened to include all triploid (2n= 27)L. binervosumagg. variants found also in W and N Ireland, SW Scotland and Cumbria. All other taxa are tetraploid, usually with 2n= 35.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1986.tb01428.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The morphology of seedlings, leaves, flowers and inflorescences, anatomy of the pod, the occurrence of extra‐floral nectaries, free amino acids of the seeds, flavonoid compounds in heartwoods, cyanogenic compounds and porate, colporate and extraporate pollen, and susceptibility to rusts, all indicate that three genera,AcaciaMiller,SenegaliaRaf. andRacospermaMartius, should be recognized. These correspond to currently accepted subgenera ofAcacia.The size of these more narrowly circumscribed genera is in keeping with the size of genera of other tribes of low diversity in Leguminosae.AcaciaandSenegaliaarose independently from the Ingeae, withRacospermabeing derived fromSenegalia.SectionFilicinaeis more advanced than sectionSenegaliaofSenegalia, and sectionsRacospermaandPukhella, both with at least some species with bipinnate foliage, are the most advanced ofRacosperma, while the other sectionsPleurinerviaandLycopodiifoliahave only phyllodinous species. Long‐range dispersal ofRacospermafrom the Australian region has occurred, but the broad pattern of distribution is interpreted in terms of plate tectonics.Racospermawas present in Australia in the late Cretaceous but did not become widespread until the general drying of the continent in the Miocene. The flora of SW Australia has been isolated from the rest of the continent by climatic barriers since the late Tertiary and has a high proportion of endemic species. Barriers to plant migration in the east have operated only intermittently and there is no area comparable in endemism to the southw

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1986.tb01429.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Investigations of mitosis in 10 populations ofAnemone nemorosaL. all indicated that this species has a chromosome number of 2n =30. No B chromosomes were found. There were no significant differences in chromosome morphology between the populations. Meiosis in the anthers, studied in three populations, was found to be mostly regular, with 15 bivalents, although occasional irregularities such as bridges and pentads were observed. Pollen viability was tested in 12 populations and although fairly low, with micro pollen grains in four of the populations, was not low enough to prevent a high proportion of fertilized achenes.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1986.tb01430.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Obligate subterranean cleistogamy, observed in a natural population ofVigna minima, is associated with the production of one or two negatively geotropic, leafy shoots and several positively geotropic, highly pigmented, leafless shoots. The latter branch profusely after penetrating the soil and produce much reduced, cleistogamous flowers. The undehisced anthers contain germinated pollen grains. The seeds developing from the cleistogamous flowers differ in size, weight and surface features from those produced by the chasmogamous flowers of other natural populations within the species.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1986.tb01431.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A new monotypic genus is described from impression and compression fossils preserved in the Senni Beds of the Lower Old Red Sandstone of S Wales. The new species has scattered reniform lateral sporangia suggesting zosterophyll affinity, but supporting anatomical evidence is lacking. The axes of the plant are characterized by occasional large surface protuberances, sometimes extended into lateral projections of variable length and morphology. Taphonomic factors account for some of the observed features of the fossils, and their unusual orientation in the sediment suggests thatTarellamay have grown on exposed point bars.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1986.tb01432.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY