摘要:

The pollen morphology of 33 Malesian and Australian taxa ofPolysciasis described, and the variation assessed by multivariate analysis. The analysis identified two main pollen types: (1) relatively small grains with a microreticulate tectum and lalongate ora (sect.Polyscias, Gelibia, Eupteronand six taxa not assignable to any of the sections as they are currently defined, (2) relatively large grains with a reticulate tectum, or which do not possess a tectum (previously unknown in the family), lalongate, lolongate or circular ora (sect.KissodendronandPalmervandenbroekia). The systematic utility of palynologial data at various taxonomic levels withinPolysciasis dicussed.

ISSN:0017-3134    

DOI:10.1080/00173139109427815

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Small fruits with clumps of monocolpate, reticulate pollen grains of theClavatipollenitestype adhering to the stigmatic surface have been recovered from mid-Cretaceous (early Cenomanian) Potomac Group sediments of eastern North America. They provide the first megafossil evidence of this important early angiosperm pollen genus. The fruits are described asCouperites mauldinensisgen.et sp. nov. They are unicarpellate and unilocular containing a single, anatropous and pendulous seed. The fruit wall is thin with distinct, tubercular protrusions enclosing spherical resin bodies. The seed wall is apparently composed of two distinct tissues, indicating that the seed was probably derived from a bitegmic ovule. The outer tissue consists of one layer of cuboid palisade cells, the inner tissue consists of longitudinally elongated cells. Fruit and seed characters indicate thatCouperitesis more closely related to Chloranthaceae than to any other magnoliid family, and support the systematic affinity suggested for most dispersedClavatipollenitestaxa. However, the anatropous seeds placeCouperitesoutside the current circumscription of the family and imply a more basal phylogenetic position.

ISSN:0017-3134    

DOI:10.1080/00173139109427816

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Pollen grains harvested by bees differ greatly in volume, thus pollen grains contribute differentially to larval and imaginal nutritional ecology, and ultimately to bee fitness. Simple proportions are inadequate when disentangling the importance of various pollen taxa found on foraging bees, their scopal loads or in their nest provisions. Disparate volumes of pollen grains are an essential feature to be considered in any foraging or dietary study. To document the importance of pollen volume on diet we mixed equal amounts (by weight) of ten morphologically diverse pollen taxa commonly collected by honey bees in the Sonoran desert of Arizona. These taxa were:Cereus giganteus, Ephedra trifurca, Fouquieria splendens, Helianthus annuus, Prosopis juliflora, andSimmondsia chinensis. Additionally, a small grain,Solanum rostratum, and two large grains,Cucurbita foetidissimaandOpuntia phaeacantha, rarely harvested by honey bees, were included in the mixture. The mixture was inoculated with calibrated spore tablets, acetolyzed, counted, and % volumes calculated. Pollen grain numbers obtained from the middle of the coverslip were compared with those along the coverslip edge (x2) with no apparent statistically significant difference. The percent by pollen grain number was compared with percentage by pollen grain volume using a Chi-square test.

ISSN:0017-3134    

DOI:10.1080/00173139109427817

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Pollen morphology ofAndruris japonica(Triuridaceae) was investigated by light and electron microscopy. The pollen is monosulcate and has a size of 22–25 μm × 25–28 μm in polar view. In the non-apertural region the exine has gemmate to nearly verrucate protrusions of 0.4–0.5 μm in diameter and 0.3–0.5 μm in height, and a foot layer of 0.4–0.5 μm in thickness. The sporoderm of the apertural region has large gemmae of 0.7–0.8 μm in diameter and 0.6–0.7 μm in height, with a thin foot layer of 0.1 μm thickness.

ISSN:0017-3134    

DOI:10.1080/00173139109427818

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The sixth volume in the series of bibliographic indices to the pollen morphology of the angiosperms initiated by G. Thanikaimoni in 1972 is analysed with respect to the three main instruments used for the description of the pollen grains, viz, light microscopy, scanning electron microscopy and transmission electron microscopy. The results clearly show that SEM studies dominate over the other two methods, TEM being the least used. The scanning electron microscope, by the very nature of its illustrations and its capacity to provide accurate information on exine structure remains the most preferred tool of pollen morphologists. The geographic origin of the authors and the languages used in the articles are also analysed.

ISSN:0017-3134    

DOI:10.1080/00173139109427819

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0017-3134    

DOI:10.1080/00173139109427820

出版商:Taylor & Francis Group    

年代:1991

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:10.1080/00173139109427814

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor