PLANTS | ANIMALS | ECOLOGY | FUNGI | GEOLOGY | GARDENING | TOOLS
MEXICAN PLANTS & ANIMALS HOME
Excerpts from Jim Conrad's
Naturalist Newsletter
Issued July 6, 2020, from the forest just west of Tepakán; elev. ~9m (~30 ft), N21.053°, W89.052°; north-central Yucatán state, MÉXICO
WILD YAM
Ten Wild Yam species -- genus Dioscorea -- are listed by CICY as occurring in the Yucatan Peninsula. Three or four species appear at the ranch, and I've had problems identifying them to species level. One problem is that the technical keys available depend heavily on having male flowers, but male flowers are at hand only briefly throughout the year. When male flowers are found, I document them. For example, currently one of our species is producing the long, spike-like head of male flowers shown below:
The leaves are particularly long and slender, with basal lobes usually somewhat round-pointed, almost sagitate. A close-up on one lobe is shown below:
In that picture also note that the slender stem is somewhat squared in cross section. The hairy, brownish flowers usually appear two or three in a cluster on short pedicels, and hang downward, shown below:
A view into a flower's throat is shown below:
These features lead to DIOSCOREA SPICULIFLORA. The 1987 Dioscorea treatment by Sosa, schubert and Gómez-Pompa Flora of Veracruz lists three varieties of Dioscorea spiculiflora occurring in Veracruz, of which the type variety spiculiflora is the one we seem to have, and which grows commonly in our part of northwestern Yucatan. Key features separating our variety from the others are that its leaves are narrow and there's lots of space between the clusters of male flowers.
The species is distributed from southern Mexico to Costa Rica, while our var. spiculiflora occurs in southern Mexico, the Yucatan Peninsula, and Guatemala.