A monograph of the genus Lilaeopsis (Umbelliferae) (America, North, South, Australia, New Zealand) [microform]
- Bib ID:
- 3287463
- Format:
- Book and Microform
- Author:
- Affolter, James Martin
- Description:
- 344 p.
- Summary:
-
Lilaeopsis is a genus of perennial, rhizomatous herbs in the Umbelliferae. Its thirteen species occupy damp, marshy, or truly aquatic habitats. The genus is well-developed in temperate and alpine zones of North America, South America, and Australasia. The group is difficult taxonomically, due to its simplified vegetative morphology. The leaves are linear or spatulate, hollow, and transversely septate. They have apparently been derived from the axis of a compound leaf. The size and shape of the leaves are readily modified by the environment. Traditionally, microscopic characters of the fruit have been emphasized to distinguish the species. This study was undertaken to revise the taxonomy of Lilaeopsis, to collect more information concerning the biology of the plants, and to throw light upon the biogeographical history of the genus. The investigation employed standard herbarium techniques, numerical analysis, and light and scanning electron microscopy.
Extensive field work in North and South America, Australia, and New Zealand was supplemented by cultivation of living material at the University of Michigan Botanical Gardens. Samples from 53 populations, representing eleven of the thirteen species, were grown in the common-garden. Data were collected concerning limits of phenotypic plasticity in response to various degrees of submergence and light intensity. The study reduces the number of species recognized from twenty-two to thirteen. Carpological characters continue to receive emphasis, but recognition of their extensive variability in some taxa resulted in the merging of several previously recognized species. There appear to have been at least two waves of migration of Lilaeopsis between North and South America, one between the eastern sides of the continents, a second between the northern Andes and southwestern North America.
High latitude migration across the southern hemisphere is the most reasonable explanation for the disjunction between South America and Australasia. The timing and mode of these migrations are uncertain, but long-distance dispersal, more favorable climatic conditions, and perhaps greater proximity of the southern land masses were probably involved.
- Notes:
-
- (UnM)AAI8314226
- Source: Dissertation Abstracts International, Volume: 44-02, Section: B, page: 0393.
- Thesis (Ph.D.)--University of Michigan, 1983.
- Reproduction:
- Microfiche. Ann Arbor, Mich.: University Microfilms International.
- Subject:
- Biology, Botany
- Other authors/contributors:
- University of Michigan
- Copyright:
-
In Copyright
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Copyright status was determined using the following information:
- Material type:
- Literary Dramatic Musical
- Published status:
- Unpublished
- Creation date:
- 1983
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