Taxonomic assessment of O. furcillata (Oxalidaceae)
Date
2005-12
Authors
Bissiengou, Pulcherie
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
The family Oxalidaceae has a worldwide distribution, but is most common in tropical
and subtropical regions. Oxalis L. is the largest genus of the family comprising ca.
800 of the 900 species. Oxalis species are annual or perennial herbs or rarely
subshrubs or trees. The current study assesses on the taxonomic placement of
O. furcillata Salter. Currently this species, comprising two varieties, O. furcillata var.
furcillata and O. furcillata var. caulescens Salter, is placed in section Foveolatae.
Members of this section have endospermous seeds and fleshy leaflets. However, both
in terms of leaf morphological and seed characters the two varieties of this species
appear to be misplaced within this section. In addition O. furcillata var. caulescens
has a unique pollen type, different from both the typical variety and the rest of the
section. Both lines of evidence thus suggest that O. furcillata var. caulescens may be
misplaced within this section. The present study thus sets out to assess the placement
of O. furcillata in general, and the placement of O. furcillata var. caulescens in
particular. A multi-disciplinary approach was followed, which included analyses of
macro-morphological (including LM and SEM analyses), biogeographical and
palynological characters. The variability of quantitative characters was assessed using
the STATISTICA 6.0 software package. Leaf dimensions, plant height, bulb length,
petiole length and palynology showed sufficient differences between the two taxa to
confirm the separate identity of these two varieties as separate species. O. furcillata
var. caulescens was thus raised to specific status as O. caulescens (Salter) Bissiengou.
The results suggest two different options in terms of the taxonomic placement of the
species O. furcillata and O. caulescens. They can either remain in section Foveolatae,
best placed near O. senecta and O. densa or may moved to the highly variable section
Latifoliolatae. But retaining them within the section Foveolatae appeared to be the
better alternative. The correct position will be established both through further
morphological analyses and correlation to the trnL-F and ITS sequence-based
phylogeny of the southern African members of Oxalis.
Description
Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2005.
Keywords
Dissertations -- Botany, Theses -- Botany, Assignments -- Botany, Dissertations -- Systematics and biodiversity science, Theses -- Systematics and biodiversity science, Assignments -- Systematics and biodiversity science, Oxalidaceae -- Classification, Oxalis -- Classification