摘要:

A palynological description of 70 species and 2 subspecies out of a total of 165 species inStylidiaceaeshows that this family is very homogeneous from a palynological point of view. A tentative phylogenetic outline is drawn on the basis of number of apertures supposing that evolution is parallel to the increase in the number of colpi.

ISSN:0017-3134    

DOI:10.1080/00173137209427641

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The rehydration of dried pollen and spores is a common technique to obtain information on nuclear condition, cytoplasmic storage materials, the intine and other aspects of pollen morphology when fresh material is unavailable. Pollen grains are rehydrated and consequently expanded by most aqueous solutions although electron microscopical examination will reveal considerable variation both in stainability and quality of expansion following embedding. That variation, we suggest, is due to substances extracted during hydration and processing. Rehydration of herbarium material with aldehyde solutions containing cations known to stabilize mucosubstances has greatly improved staining and recovery of shape equivalent to fresh pollen ofNymphoidesandMenyanthes(Menyanthaceae). It is our contention that rehydration of dry pollen with attention to the stabilization of mucopolysaccharides substantially increases the information available from herbarium material and should supplement KOH and acetolyzed specimens.

ISSN:0017-3134    

DOI:10.1080/00173137209427642

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Pollen grains ofPicea orientalis, P. sitchensis, Tsuga heterophylla,andT. mertensianawere investigated by means of light, scanning electron, and transmission electron microscopy. The fine structure of these four species, the siamese pollen inP. sitchensis,and the variations in sacci ofT. mertensianawere demonstrated. Pollen morphology ofT. mertensianadiffered from that ofPicea,and even more fromT. heterophylla.The difference in morphology ofTsugaspecies may have been due to varying rates of evolutionary change, to the modification of reproductive structure for their continued existence, or to introgression. From the differences in pollen morphology, the authors consider that the twoTsugaspecies could be assigned to separate genera.

ISSN:0017-3134    

DOI:10.1080/00173137209427643

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The pollen of most of the approximately 140 species ofLinumhas now been examined. Most have tricolpate pollen, but nineteen have been found to have multiaperturate pollen. These are distributed among three of the five subgenera usually recognized in the genus, and almost certainly are the result of three independent evolutionary routes. There is evidence that the multiaperturate condition may have evolved twice in each of two of these subgenera. It is possible, if not probable, therefore, that species with multiaperturate pollen may have evolved from those with triaperturate pollen on as many as five different occasions in this genus.

ISSN:0017-3134    

DOI:10.1080/00173137209427644

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Cedar pollen was used as bait for the chytrid,Rhizophidium,and fungal attack was common over all regions of the pollen grains although definitive evidence was not obtained to indicate that the exine was digested. The protoplast and intine appeared to be excavated by the attacking fungus without noticeable modification of the exine.

ISSN:0017-3134    

DOI:10.1080/00173137209427645

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Meconopsis x cookeiis a hybrid betweenM. quintuplinerviaandM. punicea.The parents have appreciably different pollen. The partially fertile pollen of the hybrid is intermediate morphologically between those of the parents. The significance of this example in interpreting control of pollen characters is discussed.

ISSN:0017-3134    

DOI:10.1080/00173137209427646

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Two Middle Jurassic microfloras viz. from Lilla Altona, in southeastern Scania and from the Öresund between Helsingborg and Helsingör are described. Although there are numerous Liassic elements within the microflora, exclusive Middle Jurassic species determine the age as Bajocian/Bathonian, viz.Todisporites minor, Leptolepidites equatibossus, Leptolepidites rotundus,andParvisaccites enigmatus.

ISSN:0017-3134    

DOI:10.1080/00173137209427647

出版商:Taylor & Francis Group    

年代:1972

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:10.1080/00173137209427640

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor