摘要:

SummaryTwo new divisive strategies for hierarchical classification are reported. Both use a form of ‘directed search’ to limit the number of possible polythetic splits examined. An objective method for testing the accuracy of divisions is defined. Preliminary results of tests of the two new methods against certain existing techniques have shown the former to produce superior divisions.

ISSN:0040-0262    

DOI:10.2307/1218121

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe biosynthetic pathways leading to the major groups of secondary metabolites isolated from theZanthoxylum/Fagaracomplex are reviewed and there is shown to be a common precursor in chorismic acid. The use of the compounds as chemotaxonomic markers is discussed and they are found to support the concept of a direct link between the Rutaceae and ranalian stock. The potential value of the secondary metabolites in chemosystematic analysis within the family is also briefly discussed.The alkaloids, coumarins, flavanoids and lignans of the taxaZantboxylumandFagara areexamined in detail and the distribution found to support authorities who have expressed the view that these taxa are congeneric (Zantboxylum s.l.). The chemosystematics of Zanthoxylum s.l. indicates that the genus is primitive within the family. The secondary metabolites ofZanthoxylum s.l. are used to construct a putative phylogeny of the genus and its possible “key” position in the evolution of the family is speculated upon. It is noted that the Englerian classification ofZanthoxylum s.l., and of the Rutaceae in general, appears to be unsatisfactory.

ISSN:0040-0262    

DOI:10.2307/1218122

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1973.tb03339.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryUltrastructural analysis of sieve tubes of Hamamelididae (48 species from 16 families and 12 of the 15 orders investigated) showed a rather uniform distribution of S‐type plastids (storing starch only) among this subclass. P‐type plastids (storing protein) were reported only for the genusUlmus. Some other species belonging to the Urticales contain sieve‐tube plastids storing neither starch nor protein; however, the scarce formation of minute starch grains in at least two species of the latter group joins them to the S‐type plastids.

ISSN:0040-0262    

DOI:10.2307/1218124

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryDuchesne'sManuel de Botanique(Paris, 1764) contains the first publication of Bernard de Jussieu's natural system, the only one that appeared during Bernard's lifetime. Buisson'sClasses et noms des plantes(Paris, 1779) and Durande'sNotions élémentaires de Botanique(Dijon, 1781) include publications of Antoine‐Laurent's 1774 system, which constituted an intermediary stage between Bernard's method and that of the 1789Genera plantarum, and in accordance with which the botany school in Paris was replanted.

ISSN:0040-0262    

DOI:10.2307/1218125

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1973.tb03342.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe identity of the species ofOncidiumdescribed by Jacquin (underEpidendrum)in hisEnumeratio(1760) and in hisSelectarum stirpium(1763) is discussed. The choice ofEpidendrum altissimumas the lectotype of the generic nameOncidium‐ originally made in 1874 ‐ is upheld.

ISSN:0040-0262    

DOI:10.2307/1218127

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1973.tb03344.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryA synopsis of the historical background of the orchid genusSchomburgkiaLindl., considered largely in terms of the contributions of the five major botanists who described its species. A complete bibliography for the genus is also provided.

ISSN:0040-0262    

DOI:10.2307/1218129

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1973.tb03346.x

出版商:Wiley    

年代:2019

数据来源: WILEY