Topic
Lyonothamnus
About: Lyonothamnus is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 48 citations.
Papers
TL;DR: It is found that groves are largely genetically distinct clones, indicating that they are not remnants of a once larger clonal forest, and that the two subspecies of L. floribundus are very closely related rather than being two distinct lineages dating to the Miocene, as indicated by the fossil record.
Abstract: Lyonothamnus floribundus, or island ironwood, is a relictual endemic species found on only four of the eight California Channel Islands. It has been suggested that this species is capable of clonal growth, although the extent of clonality has not been determined. We have used random amplified polymorphic DNA (RAPD) analysis to examine clonality and genetic diversity in L. floribundus. We found that groves are largely genetically distinct clones, indicating that they are not remnants of a once larger clonal forest. Our data also indicate that the population size of L. floribundus on Santa Cruz Island is closer to 1125 individuals, rather than 32 000 based on the number of trunks. The extensive clonality in this species may have a severe impact on its ability to reproduce sexually owing to limitation of pollinator movements among flowers within a single individual. In addition, our data indicate that the two subspecies of L. floribundus are very closely related rather than being two distinct lineages dating to the Miocene, as indicated by the fossil record.
26 citations
TL;DR: A renewed taxonomy within an updated temporal framework provides an important first step toward understanding the evolution, diversity, paleoecology, and paleobiogeographic history of this unusual member of the Rosaceae.
Abstract: Lyonothamnus Gray is a monotypic genus of evergreen trees endemic to California’s Channel Islands. There is one species, L. floribundus, with two subspecies, ssp. floribundus and ssp. asplenifolius. Subspecies floribundus has simple and entire‐margined leaves, while leaves of ssp. asplenifolius are pinnate and composed of three to seven primary segments. Despite its restricted modern occurrence, three fossil species have been described from Neogene paleofloras in the far western United States. Lyonothamnus mohavensis Axelrod is known from California; L. parvifolius (Axelrod) Wolfe and L. cedrusensis Axelrod, from Nevada. However, the size ranges used to segregate these species were all found to fall within the range of L. parvifolius from Stewart Valley, Nevada. Study of intact leaves reveals that the combination of (1) number of primary segments, (2) length of primary segments, (3) number of medial secondary segments per primary segment, and (4) lengths and widths of medial secondary segments is importan...
21 citations
1 Jan 1993
TL;DR: In this paper, a preliminary checklist of soil mites from Santa Catalina Island is appended, along with a sample of the soil in order to determine what impact feral animals may have on populations of soil inhabiting mites, and a depauperate soil fauna may result in a decrease in nutrients for plant growth and development.
Abstract: Several plant communities on Santa Catalina Island have been altered by trampling and over-grazing from such animals as goats and pigs. The soil beneath selected groves of Lyonothamnus floribundus floribundus was sampled in order to determine what impact feral animals may have on populations of soil inhabiting mites. Marked decreases in diversity and abundance of species were noted in heavily disturbed areas. A depauperate soil fauna may result in a decrease in nutrients for plant growth and development. A preliminary checklist of soil mites from Santa Catalina Island is appended.
5 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2000 | 1 |
| 1999 | 1 |
| 1993 | 1 |