Special Origins
All North American Drosera species except for D. anglica have a chromosome count of 2n=20. In 1955, Wood noted that D. anglica had a chromosome count of 2n=40, and hypothesized that it was of hybrid amphidiploid origin. Since the leaf morphology of D. anglica is an intermediary between that of D. rotundifolia and D. linearis and the two occur sympatrically in several locations, Wood conjectured that D. anglica likely originated from a hybrid between these two.
All North American Drosera species produce sterile hybrids. The natural hybrid D. rotundifolia × D. linearis (conventionally but incorrectly referred to as Drosera ×anglica), is also sterile but is morphologically similar to the modern D. anglica. Errors in meiosis during ovule and pollen production, however, can result in a chromosome doubling which can allow for viable seed to be produced. The resulting plants, known as amphiploids, would be fertile. Woods noted that this appeared to be an ongoing process with D. anglica speciating from D. rotundifolia × D. linearis through amphidiploidy in multiple locations. The question remains as to why D. anglica is so widespread, whereas the range of D. linearis is limited to the Great Lakes region of North America. The greater adaptability of D. anglica to varied habitat conditions could be a major factor.
Read more about this topic: Drosera Anglica
Famous quotes containing the words special and/or origins:
“Beauty, like all other qualities presented to human experience, is relative; and the definition of it becomes unmeaning and useless in proportion to its abstractness. To define beauty not in the most abstract, but in the most concrete terms possible, not to find a universal formula for it, but the formula which expresses most adequately this or that special manifestation of it, is the aim of the true student of aesthetics.”
—Walter Pater (1839–1894)
“Grown onto every inch of plate, except
Where the hinges let it move, were living things,
Barnacles, mussels, water weeds—and one
Blue bit of polished glass, glued there by time:
The origins of art.”
—Howard Moss (b. 1922)