The legend of the money tree

Dillenia indica is a plant native to tropical Asia, brought to Brazil by the Portuguese and it was a Portuguese that built up the idea of a tree that produces money. The legend says that D. Pedro I of Brazil (D. Pedro IV of Portugal) sent the fruits of this plant to Portugal with the note “In this land money grows on trees”. When the Portuguese opened the fruits they were astonished! All the fruits had patacas’ coins inside! – the Brazilian currency used on those days. This was a very extravagant way that D. Pedro found to symbolize the natural richness of Brazil. 

D. Pedro I of Brazil

As you can imagine that was a trick, Dillenia does not grow patacas nor any other currency in their fruits, but the trick was so good that the legend remained and stayed in people’s imaginary – even today people from Portuguese speaking countries keep talking about the Patacas’ tree as a hypothetical easy way to make money, but I can assure that such trees do not exist!

Imagine what it would be like if you find a coin inside this fruit...

But the mystery remains – if Dillenia don’t make patacas, how did the fruits had patacas inside without being opened before? I must say D. Pedro had sense of humor, and by using a very cheap trick he managed to keep this legend in people’s mouth until today. The Patacas’ tree is known in Brazil also as the chest-fruit tree, and the origin of this name is the key to solve the mystery. When the flowers of Dillenia are fertilized, the fruit grows in the middle as usual, however, also the petals start developing and growing around, becoming juicy, edible and protecting the fruit inside. Whatever you place in the flower (between the ovary and the petals) remains there, and obviously the coins that D. Pedro placed in the flowers remained inside until they got ripe and someone shopped the fruit. 

Chopped fruit of Dillenia indica - the coins were placed in the gap between the fleshy petals and the inner core - the real fruit! Source: http://come-se.blogspot.pt

Basically, the coins were not inside the real fruit, even though for non-botanists that’s what it looks like, the petals and all organs that are part of the flower are not considered to be the fruit, so the juicy edible petals are just that - petals and are not considered to be part of the fruit (at least, botanically speaking). For all those that are now disappointed knowing that money really doesn’t grow on trees, at least now you know how to trick a friend!

Even though the way that the fruit is formed is pretty odd, also the flowers are quite impressive, and have a lot of evolutionary clues to be demystified. From my view, one of the most interesting morphological characters of Dilleniaceae, apart from the petals that become part of the fruit, is the androecium. The androecium is known to be polyandric in most cases, which means that it is formed by many stamens (more than double the number of petals), originated by the division of common primordia.

Dillenia indica flower. Source: André Benedito

Some other morphological aspects are said to be related with basal Caryophyllales (including the centrifugally developing multistaminate androecium, persistent calyces and campylotrous ovules), but the truth is that the placement of this group among eudicots is not entirely clear yet.