Masters Theses

Date of Award

8-1986

Degree Type

Thesis

Degree Name

Master of Science

Major

Botany

Major Professor

Edward E. Schilling

Committee Members

Hazel R. Delcourt, Eugene B. Wofford

Abstract

A revision of the species placed previously in Viguiera series Maculatae (Asteraceae) was conducted to evaluate the distribution, species relationships and taxonomy. Data from flavonoid chemistry and morphology were integrated to construct a reliable and natural classification of the group which as a result of this study was redesignated to be section Eriophorae.

All of the species of section Eriophorae are endemic to Mexico. They occur primarily in montane, seasonally dry areas. Most of the species have relatively narrow distributions although there are some wide ranging ones as well.

Foliar flavonoids were found to be associated with external glands. Species exhibiting no flavonoids lack external glands. The compounds isolated were flavones and the chalcone butein. The isolation of 6 OH luteolin in this study as a free aglycone is the first report of the compound in this form. Most of the species had distinctive assemblages of compounds, with the number of compounds present varying from six to none.

Floral flavonoids included flavonol glycosides based on quercetin and four chalcone and aurone pairs. Among the chalcones isolated were two distinctive compounds. A' OMe isoliquiritigenin and 3 OMe coreopsin. The distribution of these compounds within the section was of taxonomic interest. Three species presented all the compounds isolated for the section while another species possessed no compounds.

The distribution of foliar and floral flavonoids within the section was integrated with morphological data and analyzed by numerical methods to aid in the classification of the species in the section. A total of 6A morphological characters was measured in the numerical analysis. For the cladistic analysis 23 morphological and 14 chemical characters were used. Both methods produced very similar results, and agreed in the number of subgroups present in the series, although they differed in the arrangement of species within the subgroups. Because the cladistic analysis was thought to reflect a more natural arrangement of species it was used as the basis for classification within the section.

The distinctiveness of the series within the genus, coupled with the close morphological and chemical relationships exhibited by the species of this group, indicated that a change of status from the level of series to that of section is warranted. The name Eriophorae is proposed for the section. Based on the cladistic analysis section Eriophorae can be further subdivided into three series: series Trachyphyllae (V. trachyphylla); series Adenophyllae (V. adenophylla, V. neocronquistii and V. quinqueradiata); and series Eriophorae (V. eriophora subsp. eriophora, V. eriophora subsp. poblana, V. insignis, V. oaxacana, V. puruana and V. sphaerocephala)

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