As promised, the program sees botanical history through Kewian lenses -- the program on the rubber trade, for example, doesn't mention what Britain's successful transplantation of smuggled rubber trees from Brazil did to the Brazilian rubber trade and Brazil's economy, a bit of sanitized history as told by the victor. Still, the program is fascinating, with the history of many individual plants, including the cycad (Encephalartos altensteinii) that arrived at the gardens in 1755, before Linnaeus devised his naming system, or notes from Charles Darwin on plants he brought to the garden. Only at Kew could this long history be told.
And then there's the Amazonian water lily (now called Victoria amazonica, it was originally named Victoria regis after the queen). In 1837 botanist Robert Schomburgk found this plant in the Berbice River as he was exploring British Guiana. The plant is called "water maize" in its native habitat, where it grows abundantly. The leaves can be up to 3m, or 9.8ft across, and sturdy enough to hold a small child. The flowers are huge, colorful and highly scented -- sometimes. The plant produces 40 - 50 leaves in a single season.
|Flowering Victoria amazonica,|
Amsterdam Hortus Botanicus, Ellie Swindells; Wikipedia
|Amazonian water lily at Kew Gardens; The Telegraph|
As Bean et al. wrote in 1908:
As one might infer from its enormous dimensions and extraordinarily quick growth, the Victoria regis is a gross feeder. Every fresh plant has to be supplied with several cartloads of good loam, enriched by rotted manure. The water is kept at first at a temperature of about 80 degrees F., deducted to 75 degrees as the plant becomes strong and established. Perhaps the most important desideratum is abundant and unrestricted light. With these needs supplied, the cultivation of this noblest of aquatics presents no difficulty, except that in late years a troublesome fungus has often disfigured the leaves.Flowers are a variety of pinks and whites, and the plant has an unusual mechanism of pollination. The plant's first blossoms are large and white, and female. The flowers open in the evening, and smell of pineapple, and actually heat up. The scent beckons to beetles, and when they sit on the flower, transferring pollen to the stigma, the flower closes around them. The beetles are attracting mates, and then mating inside the flower, all easier at higher than ambient temperatures. The flower reopens the following night but it is pink, it has lost its smell and it is now male, its anthers mature and ready to shed pollen. The beetle picks up the pollen and flies to the next white flower, still a female, waiting to be pollinated (source).
This is interesting in its own right. Hermaphroditic flowers, with both male and female organs, aren't uncommon, but flowers that are one and then the other are less so. Here's an extremely successful plant in its native habitat, with a reproductive trick that it shares with few plants.
This could be, like any trait, an example of what Ken discussed in his final post on the mythology of natural selection about the meandering path from then to now. Does this pollination mechanism have an adaptive advantage? Is it due to natural selection, meaning that water lilies that are male or female, or hermaphrodites, with two sets of sex organs, reproduced less successfully than the V. amazonica in this plant's natural habitat long ago, allowing V. amazonica to overrun the habitat?
Or, alternatively, did some of these flowers, those with this dynamic gender ability, perhaps for locally specific reasons in a scenario we can only guess at, increase in frequency over eons just by chance? Here a change and there, at some other time, another change until eventually the plant acquired this ability to change gender? If or how much was aided by specific natural selection for the trait, and what kind of selection are unknown, and may not even be knowable. Indeed, this may not be the most energy efficient way to reproduce, nor the only way the plant could reproduce. It just happens to be the way that currently works.
|Modified from Google Images images|