Layia discoidea
| Layia discoidea | |
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| Species: | L. discoidea
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| Binomial name | |
| Layia discoidea | |
Layia discoidea is a rare species of flowering plant in the daisy family known by the common name rayless tidytips, or rayless layia. It is endemic to California, where it is known only from the Diablo Range in southern San Benito County and far western Fresno County. It is a member of the serpentine soils flora. This is an annual herb growing a small glandular stem to a maximum height of about 20 centimeters. The thin leaves are generally lance-shaped, but the larger leaves on the lower part of the stem are usually lobed. Unlike other tidytips species, which are known for their sharply white-tipped yellow ray florets, the rayless tidytips has no ray flowers or real phyllaries. The flower head is a cluster of many golden disc florets with a base of bractlike scales. The fruit is an achene with a short scaly brown pappus.
Genetic analysis performed on this species suggest that it evolved directly from Layia glandulosa in what may be an example of both allopatric speciation and peripatric speciation.[1] Layia discoidea looks quite different from the white-rayed Layia glandulosa, and it lives in a specialized habitat, but the two species are genetically very similar and produce robust, fertile hybrids when crossed.[2]
References
- ^ Baldwin, B. G. (2005). Origin of the serpentine-endemic herb Layia discoidea from the widespread L. glandulosa (Compositae). Evolution 59:11 2473-79.
- ^ Gottlieb, L. D., S. I. Warwick and V. S. Ford. (1985). Morphological and electrophoretic divergence between Layia discoidea and L. glandulosa. Systematic Botany 10:4 484-95.
External links
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