Habilla, RHYNCHOSIA RETICULATA

Excerpts from Jim Conrad's
Naturalist Newsletter

from the February 14, 2016 Newsletter issued from Hacienda Chichen Resort beside Chichén Itzá Ruins; limestone bedrock; elevation ~39m (~128ft), N20.675°, W88.569°; central Yucatán state, MÉXICO
HABILLA, THE LITTLE LIMA BEAN
A vine twining among bushes at the edge of a little dirt road through the woods bore compound leaves with three leaflets and orangish-yellow flowers atop a long stem, or peduncle, as shown below:

With those trifoliate leaves and "papilionaceous," bean-type flowers, the vine was clearly a member of the huge Bean Family, and just because so many species of that family exist, often its species are hard to distinguish. However, the flowers were fairly idiosyncratic with their long-hairy sepals and long lower petals -- the wings and keel -- so maybe that would help. The early-morning, dew-covered blossoms are shown close-up below:

The vine also bore distinctive, legume-type fruits, looking a lot like Lima bean fruits, which also was interesting, as shown below:

When you have a Bean Family vine with trifoliate leaves and yellowish flowers with elongate wings and keels, especially if its parts are hairy, you'd do well to think of the genus Rhynchosia, of which six species are listed for the Yucatan. Googling images of the six species quickly turned up ours, which is RHYNCHOSIA RETICULATA, a commonly occurring vine in disturbed areas such as pastures, roadsides, along fences and such, from Mexico and the Caribbean area south through Central America to Brazil in South America. Among the Yucatan's species it's enough to notice the hairiness and especially long wings and keel to know you have Rhynchosia reticulata.

This vine lacks a good English name but the Spanish one is so appropriate that it deserves to be used. It's "Habilla," a "haba" being a Lima bean, and "-illa" being a suffix meaning "little," so Habilla means "Little Lima Bean," though probably no one calls it that in English, other than I.

Habilla seems to be a largely ignored little vine, though one reference says that livestock gladly feed on it. I'll bet that if enough of them could be found the Lima-bean-like beans would make good eating.