Oregon State University
| |
C.V. |
Publications |
Presentations |
R language |
Software |
Astragalus references |
Courses |
Systematics |
Ophelia |
Journals |
And I look at varieties which are in any degree more distinct and permanent, as steps leading to more strongly marked and more permanent varieties; and these latter, as leading to sub-species, and to species.
- Darwin
| Research
Program Infraspecific ranks (i.e., subspecies and variety) have been considered a pathway to speciation. As variation increases it leads to an unstable state where variation can no longer be maintained, resulting in divergence. Others have considered infraspecific taxa to be minor novelties (e.g., geographic races) which only serve as a distraction from the fundamental unit of biology, the species. I've chosen to investigate infra-species as a potential pathway to species by investigating the most taxonomically complex species in the U.S. flora: Astragalus lentiginosus (Fabaceae). My research focuses on the question of what are infraspecific taxa and do they appear to be significant in the process of speciation. My choice of organism is the legume Astragalus lentiginsus. Consisting of 35 varieties, this is the most taxonomically complex species in the North America Flora. This research provides three different methodological perspectives on A. lentiginosus: morphological (the phenotype), chloroplast microsatellites (seed flow), and amplified fragment length polymorphisms (nuclear markers, some of which may be under selection). |
|
Astragalus
lentiginosus
...the most
variable
of all Astragali (Jones 1923: 123)...an excessively polymorphic complex which embraces a range of variation far greater than can appear reasonable (Barneby 1964: 912) Visit my Astragalus lentiginosus website, to shed some light on the most taxonomically complex species in the North American Flora. |
|
|