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SUMMARY
t has to be noticed, that cactus enthusiasts as well as the well-established authors, which rate themselves among the specialists for the Genus Echinocereus, hit on problems with the knowledge of the section Wilcoxia. The authors Wolfgang Blum, Dieter Felix and Dieter Waldeis make an attempt now, to bring light into the darkness of the basics of nomenclature and taxonomy within the section.
In the chapter material and methods they describe their applied research methods and basics. These are in detail:
- The so called subspecies concept for a taxonomic classification.
- The field investigation based on 15 journeys to the habitats in Texas, Nuevo Leon, Coahuila, Tamaulipas,
San Luis Potosi and Queretaro as well as on their picture archives with all the slides and digital recor-
dings.
- DNS analyses, SEM pictures and analyses of the isoenzymes, all in all research methods which are
applicable nowadays due to the technical progress and which are considered as further steps on the way
to a scientifical correct grading.
- The authors investigate and describe the roots of Wilcoxia, which are genetically stated and therefore a
very important issue, which had not been considered in the morphology so far.
- Investigation and description of the structures of the vascular bundle, which is variable within the species
and subspecies of this section and therefore a further character for the classification. Example is E.
schmollii, where the vascular bundle consists of several wooden threads, which give the plant a strong
flexibility.
- Essential investigation of the herbar specimens for a proper classification of plants and the review of the
natural habitats (64 different herbarium sheets in total).
Main part of the publication is the chapter “The Taxa” where first of all the section Wilcoxia is described. Based on the new findings the authors have splitted the section into 2 groups:
- Schmollianae: E. schmollii
- Poselgerianae: E. poselgeri, E. poselgeri ssp. gerhardii, E. tamaulipensis, E. kroenleinii, E. waldeisii,
E. leucanthus
The publication continues with the description of all species and subspecies. Synonyms and the taxonomical development are available as well as common and detailed descriptions of part of plants like body, spination and so on. There are shown original descriptions for all taxa, combinations (partly in extracts), excellent color pictures from the habitats, pictures from plants under greenhouse conditions and from the most important herbarium specimens.
Further part of this book is the first description of E. poselgeri ssp. gerhardii. This plant can be distinguished from the nominate type amongst others by higher number of radial and central spines and its habitat on a higher altitude.
The general illustration section and comparative datas contain several tables with an overview of significant characters and appropriate pictures of seeds, spines and cross-sections of the fruits.
It contains also an identification key, the classifications developed by famous botanists and field explorers, the necessary special protection from the point of view of the authors and the IUCN Red List; further the representation of some hybrid plants, recommendations how to cultivate Wilcoxia, a comprehensive bibliography, a detailed index - and last but not least as a special highlight - a phylogenetic tree based on the analyses of the isoenzymes, drawn up by Helmut Walter.
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