A New Tabular and Diagrammatic Method for Displaying Artificial Hybridization Data, with an Example from Aphelandra (Acanthaceae)

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Abstract
In light of the continuing use of artificial hybridizations in plant systematics and certain inadequacies of traditional methods of displaying crossing data, a new technique is described for presentation of crossability indices. The matrix of crossability indices is first presented as a series of frequency distributions for each species. The "frequency distribution table" is a concise and useful method for reporting a large data set involving pairwise comparisons. All data are presented, and any of several coarse or fine grained patterns of crossing relationships are readily apparent. The frequency distribution table simplifies and encourages the application of numerical methods of summarization and analysis. "Crossability maps" are constructed to display the relationships suggested by the crossability indices.Each map exhibits all connections made between taxa at or above a given crossability level, providing a simple visual display of the taxonomic structure suggested by the results of artificial hybridizations. These diagrams greatly facilitate discussion of the systematic significance of the results of hybridization programs.