摘要:

The validity of the separation of the diatom genusPlagiodiscusfromSurirellahas been investigated by light and scanning electron microscopy of the two original constituent species ofPlagiodiscus, P. martensianusandP. nervatus,and ofS. gemma,the species ofSurirellawhich has been generally thought to have most in common withPlagiodiscus.On the basis both of the general valve structure and of some rather unusual features which are described here for the first time,Plagiodiscusis confirmed as a genus separate fromSurirella.Other species ofSurirellawhich have features in common withPlagiodiscusandSurirella gemma,namelySurirella neumeyeri, S. baldjickii, S. bertillonii, S. foliata, S. contiguaand S.gemmoideshave been examined in greater or lesser detail as material has permitted; the systematic position of these organisms is briefly discussed.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01496.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Population differentiation was studied in 32 accessions belonging toSolariumL. sectionSolarium (Maurella);these accessions represented 20 species of four differing ploidy levels. A study of discordance demonstrated that the species exhibit considerable inherent discordant variation; it also provided an estimate of the relative variabilities of characters within these populations, and the consistency with which they differentiate populations.Hierarchic clusters, obtained using the single‐link cluster method, confirmed the relative importance of the different classes of characters used for differentiation within this section. Similarly, the hierarchic clusters generally supported earlier taxonomic decisions.The use of a non‐hierarchic cluster method provided the most interesting data on differentiation within the sectionSolarium,particularly for genome relationships of the polyploid taxa. This clustering pattern fitted well with known genome relationships, while also suggesting putative ancestors for other allopolyploids; suggestions deriving retrospective support from the hierarchic dendrograms. The progenitors suggested by tliese two clustering methods supported data derived from orthodox taxonomy, comparative morphology, hybridisation studies, the artificial synthesis of polyploids and seed protein band patte

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01497.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A hybrid swarm betweenAcacia brachybotryaandA. calamifolia,involving plants referable toA. grayana,was studied in detail. Plants representing the range of variation found within the hybrid swarm were examined morphologically, chemically and ecologically in an attempt to document hybridisation and to determine their status. Plants referable toA. grayanaare confirmed as hybrids, and other intermediate plants are determined as backcrosses to either parent. Phyllode morphology, pollen polyad form and flavonoid composition prove extremely useful in identifying the various elements of the hybrid swarm. Various other aspects of the biology and ecology of the plants in the hybrid swarm are noted.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01498.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Tetrataxis,a monotypic endemic of Mauritius, has been known since the 1790s only by the type collection in the Paris Herbarium. Now a colony of seven individuals has been discovered in a valley south‐east of the type area. The small trees grow in saturated soil in a low open wet forest. Vegetatively, they resemble the more commonSyzygium or Eugenia.Characteristics of the pollen and seed, anatomy of stems and leaves, and an approximate chromosome number are reported for the first time. A lectotype is selected from material of the original collection.Tetrataxisdisplays a number of advanced characters. It appears to have no close affinity to any single member of the famil

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01499.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01496a.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY