The other day when I noticed the humble little vine with quarter-size flowers shown below:
This plant is common here, twining among cacti, henequen plants and
branches of dead trees. They like light. You'd never imagine that they'd have anything to
do with milkweeds until you look into the little flowers' throats with a lens, and then
you see the pretty complexity there all set down along themes recognizably
Sigrid is on sabbatical so I sent the above picture for identification to my friend Ulli back in Bayreuth. He was tickled with the picture, for the little vine, despite its commonness here, is endemic, in the whole world found only in the Yucatán. It's DICTYANTHUS YUCATANENSIS, formerly called Matelea yucatanensis.
The plant is so low-key that I doubt it has any common name. However, Weakley's Flora of the Carolinas refers to species in the genus Matelea as Spinypods, so maybe a good English name for this vine is the Yucatan Spinypod.