No abstract

Summary Baum, B. R.: Combining trees as a way of combining data sets for phylogenetic inference, and the desirability of combining gene trees. ‐ Taxoni 41: 3–10. 1992. ‐ ISSN 0040‐0262. A procedure of combining trees obtained from data sets of different kinds, similar to Brooks's technique but for a different purpose, with the aim of combining these data sets, is detailed along with examples used in five unrepeated combinations from a total of 15 published datasets. The procedure does not adjoin raw data sets, but instead combines the binary‐coded factors of the trees, each tree from a different data set, together. This allows the combining of data that are only available as pairwise distances with data obtained directly from characters of the organisms. It economizes the analysis of combined nucleotide sequence data which can be very large, and preserves information for each kind of data in the combination. The procedure allows for missing data as well, and can be regarded as a new consensus method ‐ mathematical properties have yet to be investigated. The desirability of combining gene trees, obtained from molecular data, to enable the inference of species trees is discussed in light of using this procedure.

Quantitative phytochemical variation was determined from roots and inflorescences of native plant populations in the genus Echinacea. Specimens were collected in situ throughout the natural range of each putative taxon and transplanted to greenhouse cultivation. Ethanolic extracts from individual plants were separated by reversed-phase HPLC to quantify the alkamides, polyenes/ynes, and phenolics, and then grouped by age and taxonomically, according to a recent morphometric taxonomic revision of the genus. Canonical discriminant analysis revealed that cichoric acid, the diene alkamides 1-3 and 7, and ketoalkene 24 were the best taxonomic markers. Mean content for each of 26 phytochemicals revealed useful agronomic information, such as those varieties and organs with the highest accumulations, as well as the optimal age and growth conditions for each variety. The highest amounts of cichoric acid were measured from the older, wild inflorescences of E. pallida var.sanguinea, whereas the highest quantities of the alkamides 1-3 and 7 were present in roots of wild and transplanted E. purpurea. Baseline phytochemical data and chromatographic profiles for all types of wild Echinacea may be used for protection of wild stands, germplasm identification, and crop improvement.

A survey of the phytochemistry of Panax quinquefolius L. (North American ginseng) collected from wild populations in Ontario, Quebec, Maine, Vermont, and Wisconsin was undertaken. Reverse-phase HPLC was used to determine the natural variation of levels of ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd and their total in leaf, stem, and root of authentic wild-grown material. The totals in roots varied from 1 to 16%, with the greatest number of individual samples having 4-5% total ginsenosides. The lack of ginsenoside Rf in roots of authentic wild populations confirmed its status as a phytochemical marker differentiating American and Asian ginseng. Ten geographically isolated wild populations were collected, and several showed significant variation in the levels of major ginsenosides. There was no statistical difference in mean ginsenoside content between wild and cultivated P. quinquefolius roots at 4 years of age, suggesting there is no phytochemical justification for wild crafting. Baseline data on total ginsenoside levels for authentic wild P. quinquefolius reported here provide reference levels for quality assurance programs.