Crescentia alata is a species in
the trumpet-flower family Bignoniaceae, native to southern Mexico and Central
America south to Costa Rica.
It is a small tree growing to 8 m tall. It has hard, cannonball-like fruit
7-10 cm diameter, that are difficult to break into. It is believed that these
fruit characteristics evolved as a defense mechanism against seed predation.
However, it seems to be a counter-productive strategy, as the seeds inside
the fruits never germinate unless the fruits are broken open, and with the
exception of horses and humans, no animals break open the fruits.
While it has been observed that domestic horses may smash the fruit with their
hooves and eat the pulp and seeds (suggesting that they may serve as seed
distribution vectors), horses were only very recently (in evolutionary time)
introduced to the native range of C. alata, which implies that C. alata evolved
thick-walled, impenetrable fruits long before the introduction of horses to
its native range. So the question remains: how did C. alata evolve a defense
mechanism (impenetrable fruits) that entirely prevents the germination of
Daniel Janzen suggested that Gomphotheres (large, prehistoric, sloth-like
mammals) may have previously been responsible for the dispersal of C. alata
seeds. With their extinction, C. alata became threatened with the possibility
of habitat loss and suffered an extremely limited ability to migrate, but
the introduction of a new vector, in the form of domestic horses, has allowed
the species to maintain its viability. C. alata is, not surprisingly, most
often found in open areas, such as pastures and fields. It is also cultivated
for its gourd-like fruits, which may be hollowed and dried and used as containers
for food and drink.
The fruit plays a role in the Popol Vuh (book of myths of the Mayan civilization).
After the first generation of hero twins, 1 Hunajpu and 7 Hunajpu, fail and
are killed in the ball game in Xibalba, the demonic Xibalbans hang their skull
in this tree, thus the resemblance of the fruit to skulls and the carrion
smell of the tree in flower (pollinated by flies). The skull later spits in
the hand of the Xibalban princess Ixquic, thus impregnating her and begetting
the second, successful generation of Maya Hero Twins.
The seeds are edible and high in protein with a licorice-like sweet taste,
used in El Salvador to make a kind of horchata.