Ian Crown took today's Botany Photo of the Day on his farm in Puerto Rico, where he planted the featured specimen almost a decade ago. He included a short write-up with the image, which we here include as the first section of the day's entry.
"I planted the Paullinia cupana maybe 8 years ago, and I remember seeing references to it being either a vine or a shrub. In a sense, these references are correct, for years of selection by people wanting an easier harvest led to shorter and fuller growth; but the tendrils identify this "cultigen" as a vining shrub trying to reach for support. I rarely have enough time to make morning coffee when I am on the farm, so I frequently pop out a Paullinia seed (with its distinctive white powdery cup attached to the basal end) and crush it in my mouth just enough to release the caffeine and other alkaloids. Though rather bitter, it is a great pick-me-up. The flowers are also quite beautiful. But the plants? The fact that we did not provide support means that we have heaps of guaraná with tendrils reaching everywhere but with nothing to fasten on to; they therefore look like brush piles. My morning wake up plant".
Sapindaceae (soapberry family) consists of between 140 and 150 genera and between 1400 and 2000 flowering plant species that are distributed throughout the world's temperate and tropical regions. The genus that includes today's plant, Paullinia, is, along with the maples, one of the family's largest. It derives its name from its European discoverer, the 18th century German botanist Christian Franz Paullini, and counts liana (woody climbing plants), tree, and shrubby species among its ranks, the majority of which are native to Central America, the Caribbean, and northern South America (Brazil, Venezuela, Peru).
Paullinia cupana can grow to a height of 12 metres in its native habitat, which is centered in Amazonian Brazil. The plant puts forth dense clusters of small round fruit, the shells of which range from red to orange in colour. When the fruit opens to reveal its shiny black seed, these clusters tend to resemble a collection of gazing eyeballs yoked together, a trait that has inspired several legends concerning the plant (See here for more information). It derives its common name, guaraná, from Satere-Mawe, the language of one of Brazil's native tribes. The Guarinis—the tribe that, historically, has most regularly treated the plant as an edible—dry and roast the seeds, subsequently including them in a paste that serves a wide variety of culinary and medicinal functions. That is to say that beyond its raw power as a stimulant—which makes it a quite lucrative crop in the South American beverage business—the plant has also served as a treatment for digestive problems and as a means by which to thin the blood.