Botanic Notables: A Flower That Plants Its Own Seeds

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Botanic Notables: A Flower That Plants Its Own Seeds

December 6, 2009
02:11pm
Photo by: Alex Popovkin

 

 

Most plants try to disperse their seeds far and wide. That way, if a flood or fire kills the parent plant, at least the progeny will be spared. Moreover, any plant can be a competitor for nutrients, so the further flung the children, the better. Geocarpic plants are exceptions to this rule. These rare angiosperms prefer to keep their young close to home—actually, they don't even leave the nest before settling into the ground. By depositing their seeds in the ground, geocarpic plants are their own so-called seed sowers. 

Geocarpy is an adaptation to harsh environments. In a landscape with little arable soil, a plant's seeds are unlikely to happen upon another good spot to grow. Geocarpic species have evolved mechanisms to keep their seeds close by, where they have a good chance of growing. The mechanism is often gravity: pliable branches bend under the weight of maturing fruits, burying the plant's developing fruit (diaspore). Peanuts are a well-known example of geocarpy.

Geocarpy is pretty uncommon, so Alex Popovkin, a botanist in eastern Brazil, was excited to discover a new species that displays the behavior. The scientist's assistant first noticed the tiny plant in 2009, behind a backyard bush. A new plant in Popovkin's yard in rural Bahia is a notable event: In the twelve years he'd lived there, Popovkin has catalogued over 800 plant species growing in his land. Popovkin brought the plant indoors to observe its growth. 

As its fruits mature, the tiny, inch-tall plant drops its branches to the ground and deposits them in soft soil or moss. Scientists soon identified it as a new species, and named it Spigelia genuflexa, referring to the "bending of its infructescence branches to the ground, figuratively evoking an image of genuflection."

Lena Struwe, a botanist at Rutgers who assisted Popovkin in studying the new species, told the BBC, "In this species, it is most likely that because it is so short-lived (just a few months) and lives in small fragments of suitable environments, the mother plant is most successful if she deposits her seeds right next to herself, [rather than] spreading them around far into less suitable environments."

For Popovkin, a Russian emigré who lived in New York City before moving to Brazil, the new plant was the culmination of a long journey. "It's taken me 30 years, from my days as a volunteer at the greenhouses of the botanic garden of the University of St Petersburg, Russia, to realise my dream of living in the tropics and studying its plants up close."

More photos of Spigelia genuflexa are here