Thesis
SYSTEMATIC IMPLICATIONS OF MICRO- AND MACROMORPHOLOGY IN BERBERIS SENSU LATO (BERBERIDACEAE)
Washington State University
Master of Science (MS), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004579
Handle:
https://hdl.handle.net/2376/124619
Abstract
This study examines systematically important morphology within Berberis L. (Berberidaceae), including the segregate genera Alloberberis C.C. Yu & K.F. Chung, Mahonia Nutt., and Moranothamnus C.C. Yu & K.F. Chung. Generic taxonomy of Berberis sensu lato has been contentious, though both a broadly circumscribed Berberis and the recently circumscribed segregate genera have been recovered as monophyletic. While the diagnosis of taxa and clades within Berberis s.l. has been drawn using discrete morphological characters, these characters are often poorly defined or only described in detail for a small and phylogenetically biased sample of species. Here, we attempt to critically define important morphological characters and their variation across the entirety of the genus.Examination of leaflet surfaces using scanning electron microscopy found significant variation in both epidermal outgrowths and epicuticular waxes, which have both previously been characterized as invariant when present. Abaxial papillae in most of Berberis sensu stricto formed a pavement of irregular shapes. Round and tall papillae were mostly restricted to the clade of Mahonia referred to as the “Occidentales” but were also found in the anomalous species B. hypokerina Airy Shaw (Berberis s.s.) and the monotypic Moranothamnus. Abaxial papillae of Alloberberis formed a complex pavement of ±round outgrowths. Epicuticular wax crystals mostly conformed to previously reported tubules, but we also report granules, platelets, crusts, and large curled structures. Adaxial platelets interspersed within a tubule layer were found in all samples of the Paniculatae clade.
Based on examination of herbarium specimens and living individuals, we define five models of modular aerial shoot system arrangement built from four differentiated shoot types (dolichoblasts, cataphyllous brachyblasts, foliaceous brachyblasts, and inflorescence shoots), in contrast to a “monomorphic” vs. “dimorphic” dichotomy previously employed. A multiple correspondence analysis of 14 morphological characters (10 independent of shoot model) indicates that our models are slightly better at explaining overall morphological diversity than existing segregate genera. Ancestral character state reconstructions using a published phylogeny were largely inconclusive for nodes connecting segregate genera, as well as for interior nodes of Mahonia with respect to suppression of axillary buds of the dolichoblast.
Metrics
2 File views/ downloads
35 Record Views
Details
- Title
- SYSTEMATIC IMPLICATIONS OF MICRO- AND MACROMORPHOLOGY IN BERBERIS SENSU LATO (BERBERIDACEAE)
- Creators
- Alexander John Wright
- Contributors
- Eric H Roalson (Advisor)Jeremiah W Busch (Committee Member)Andrew McCubbin (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 128
- Identifiers
- 99900898739901842
- Language
- English
- Resource Type
- Thesis