ISSN:0017-3134    

DOI:10.1080/00173138909427437

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This is the first of two papers detailing pollen morphology and evolution with the tribe Embothrieae comprising eight genera and ca. 56 spp. The present paper examines pollen of subtribes Buckinghaminae (Buckinghamia; 2spp.,Opislhiolepis; 1 sp.), Stenocarpinae (Strangea; 3 spp.),Stenocarpus(ca. 27 spp.) and Lomatiinae (Lomatia; ca. 12 spp.) in the light microscope and scanning and transmission electron microscopes. Pollen is medium-sized, oblate, foveolate to microreticulate to reticulate, and predominantly columellate with a complex modified postvestibulate aperture morphology. Pollen data indicate ties betweenLomatiaandStenocarpuson the one hand andStenocarpusandStrangeaon the other. ThoughBuckinghamiaandOpislhiolepishave been placed in the same subtribe, the unique combination of pollen features in each suggests only a remote relationship to each other as well as to remaining Embothrieae. Comparisons to the remaining genera of Embothriae (Embothrium, Oreocallis, Telopea) and overall analysis of pollen evolution within the tribe are detailed in the subsequent paper.

ISSN:0017-3134    

DOI:10.1080/00173138909427438

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A detailed study on the morphology of pollen and orbicule on nine species of the genusEuphorbia, has been carried out by LM and SEM. Four pollen types have been distinguished and a key for their identification is presented. Distinct morphological diversity ofEuphorbiaorbicules is evident. The morphology of the orbicules is not always in accordance with that of the pollen types.

ISSN:0017-3134    

DOI:10.1080/00173138909427439

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The pollen walls of the “primitive” or lower Epidendroideae (Orchidaceae) were examined with SEM and TEM to determine whether or not pollen wall ultrastructure would have systematic implications. Pollen wall ultrastructure is indeed in some way a reflection of the “make-up” and the function of the pollinia, and can be used as a referee to classification schemes of epidendroids. The various types of exine structure are correlated with the tribes. Tectate exines with columellae and a more or less compact foot layer are seen as primitive (found in many basic Vanilleae), while either the reduction or even the absence of a foot layer (in advanced Vanilleae, in Arethuseae and Gastrodieae) or of columellae or even of the tectum itself (as in Triphoreae) should be regarded as advanced characters. The tribe-inherent “typical” exine is found in tetrads/polyads only in the outermost walls, while all walls inside the tetrads/polyads have an extremely reduced and fragile exine: often incoherent sporopollenin particles are embedded in the inline. Those—as we call them—“weak exine regions” may act as germination zones; therefore such pollen grains should not be seen as monoporate. Many uncommon, peculiar pollen wall characters occur both in Annonaceae and Orchidaceae. This unexpected, surprising result makes you reconsider current theories on the evolutionary significance of the pollen wall both in by no means related angiosperm families and in the angiosperms as a whole.

ISSN:0017-3134    

DOI:10.1080/00173138909427440

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The characteristic Mesozoic pollen genusEucommiiditesis described from pollen organs and seeds recovered in Cretaceous strata of North America and Europe. The pollen organs are from the lowermost Upper Cretaceous (Cenomanian) of Texas and are referred toErdtmanitheca texensisgen. et sp. nov. They are spherical heads, composed of numerous, densely crowded, radiating pollen sacs that contain abundant well-preserved pollen. Combined LM, SEM and TEM investigations show that the pollen grains each have a distinct distal colpus flanked by two lateral colpi in an equatorial position. Pollen wall ultrastructure is gymnospermous with a thick lamellate inner layer (endexine) and an outer layer (ektexine) composed of a granular inner part and a homogeneous outer part. The endexine is thickened in the region of the colpi. Small seeds from the Lower Cretaceous (upper Berriasian to Valanginian) of Bornholm, Denmark contain abundantEucommiiditespollen in their micropyles. The seeds are referred toErdtmanispermum balticumgen. et sp. nov. They are ovoid, and weakly triangular in transverse section and gradually taper at the apex into an elongated tube. The megaspore membrane is granular and well developed, and apparently surrounded by three separate tissues interpreted as nucellus, a thin inner integument and a sclerified outer envelope.Eucommiiditespollen in the micropyles of the seeds has a laminated endexine and an ektexine comprising two homogeneous parts separated by a granular layer. Réévaluation of other seeds known to containEucommiiditespollen indicates that they share significant similarities withErdlmanispermumand that they may have been produced by closely related plants. Comparison of “Eucommiiditesplants” with other seed plants suggests that they are probably most closely related to the anthophytes comprising Bennettitales, Pentoxylales, Gnetales and angiosperms.

ISSN:0017-3134    

DOI:10.1080/00173138909427441

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The spores of sevenCheilanthesSw. species that grow in the Northwest Region of Argentina were studied with LM, SEM and TEM.

ISSN:0017-3134    

DOI:10.1080/00173138909427442

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In two small mountain basins of the Ligurian Apennines the relationships between recent pollen spectra and vegetation were studied. Local pollen dispersal was emphasized by comparing each surface sample with the corresponding vegetation. The extralocal and regional pollen rain was observed in surface samples of the peat bogs in the small basins through the relationships between these spectra and the composition of the vegetation of the catchment basins. For the quantitative valuation of the latter, vegetation maps and a more local system of direct counting were employed. In this way quantitative information about pollen representation (R/P) of many arboreal, shrubby and herbaceous plants was obtained; however, for the moment the value of the results should be considered local while awaiting wider comparisons.

ISSN:0017-3134    

DOI:10.1080/00173138909427443

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

M. Kedves, 1986. Introduction to the palynology of pre-Quaternary deposits. Parts I and II. Studia Biologica Academiae Scientiarum Hungaricae 19–20. Published by Akadémiai Kiadó, Publishing House of the Hungarian Academy of Sciences. Budapest. Price not quoted. Reviewed by Mervi Hjelmroos.

ISSN:0017-3134    

DOI:10.1080/00173138909427444

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0017-3134    

DOI:10.1080/00173138909427436

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor