from the November 22, 2009 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
KIKCHÉ
Another very common small tree is calling attention to itself these days not because its flowers are so pretty but rather because its massive, brown fruiting clusters are so messy looking -- as shown above. Northerners will think the tree's pinnately compound leaves look a lot like those of Blacklocust trees, and that's not a bad observation since this is Kikché, sometimes called Palo de Arco or "Bow-wood", APOPLANESIA PANICULATA, a member of the Bean Family, like Blacklocust.

If you look closely at the brown masses of fruits you'll see that something pretty is going on at a small scale, despite the large-scale messiness, seen below:

What you have there is a single oval, olive-brown, one-seeded fruit at the base of which five reddish- brown, veiny, leathery, elongate lobes emerge, like the arms of a star. Each lobe is a much enlarged sepal, or calyx segment. During flowering, the sepals looked more or less normal, but once pollination occurred and the corolla dropped off, the sepals grew like crazy until they formed this starry collar below the fruit. That's pretty unusual but a few other species do it in various plant families. I think the lobes help disseminate the fruits by wind. Sepals expanding after flowering are said to be "accrescent."

The fruit is a one-seeded legume. Most legumes contain several seeds in a row, so this is another unusual feature. On the legume, notice the dark brown bumps. Those are glands, and in fact the tree has lots of glands, something again a bit unusual for a tree in the Bean Family. Look at the brown glands embedded in a veiny leaflet held up against the sun below:

Aromatic oils in those glands must be the source of the fragrant, spicy odor smelled when Kikché's leaves are crushed between fingers.

All those unusual features have made it hard for taxonomists to figure out how to classify Kikché. Before it was assigned to the genus Apoplanesia it was placed in Eysenhardtia and Microlobium.

In Maya "kik" means "blood" and "ché" means "wood," so this is the "Bloodwood Tree," so named because if you hack the slender, scaly-barked trunk with a machete it exudes reddish sap. María Luisa Vázquez de Ágredos Pascual's fascinating Los Colores y las Técnicas de la Pintura Mural Maya, available as a free PDF download on the Internet (Google the name for the link), lists Kikché as one of the most important sources of the ancient Mayas' red dyes for mural painting.