DOE OSTI2012
The large-flowered fiddleneck, Amsinckia grandiflora (A. GRAY) GREENE (Boraginaceae), is a rare annual forb native to the California winter annual grasslands. Amsinckia grandiflora germinates with the onset of fall or early winter rain, grows vegetatively throughout the winter, flowers in the early spring, and sets seeds and dies prior to the summer drought, a pattern observed in most of the herbaceous species of the California winter annual grasslands (Heady, 1990). Of the fifteen species in the genus recognized by Ray and Chisaki (1957a, 1957b), A. grandiflora is one of four heterostylous species with highly restricted distributions that are likely ancestors of the weedy, widespread, and homostylous congeners (Ray and Chisaki, 1957a, 1957b; Shoen et al., 1997). As a heterostylous species, A. grandiflora produces pin and thrum flower forms (also known as morphs) (Figure A1). Each individual plant has only one type of flower. An exerted stigma and anthers within the corolla tube characterize pin flowers. Thrum flowers have the opposing morphology, with the stigma within the corolla tube and exerted anthers. Characteristic of the genus, each flower morph has four ovaries at the base of the style, each of which matures into a seed, known as a nutlet. Thus, each flower can produce a maximum of four nutlets.
54 ENVIRONMENTAL SCIENCES↗