Excerpts from Jim Conrad's
Naturalist Newsletter

from the May 5, 2007 Newsletter issued from Sierra Gorda Biosphere Reserve, QUERÉTARO, MÉXICO

Down at the end of the reservoir where Spot-breasted Wrens sing and the vegetation is darker and ranker than elsewhere, scrambling into trees there's a woody vine so gloriously decked with brightly yellow, two-inch-long flowers that you feel glad just seeing it all. You can see what I mean below:


The vine almost reminds me of the Yellow Jessamine that used to flower so prettily in Mississippi about when Purple Martins arrived in spring, but this is a much more robust plant. It's MACFADYENA UNGUIS-CATI, often called Cat's Claw in Englis. It's a member of the Bignonia Family, along with North America's Trumpet Creeper vine and Catalpa trees. In the tropics Cat's Claw can be confused with the much-planted Allamanda, which is another vine with large, yellow, tubular flowers. Anatomically, however, the blossoms are very dissimilar, and the two species reside in different families.

You can see where the vine gets its Cat-claw name below:


That picture shows that the vine bears opposite, compound leaves. Each leaf consists of two leaflets, and where the leaflets' stalks, or petiolules, unite often there emerges a three-fingered, grappling-hook-like "compound tendril." Each tendril "finger" ends with a very sharp, stiff, curved hook. Most leaves do not bear these three-parted tendrils. The cat-claw tendrils are mostly restricted to elongating shoots.

This is another of those native Mexican plants behaving neighborly in our local ecosystems, but in other parts of the world becoming a troublemaker. Australians regard it as "one of the most destructive exotic vines" degrading their rainforest communities. Even in the US Deep South many consider it a noxious weed. One writer in Florida posting to a gardener's forum calls it an "extremely horrible plant. It is a Category I Exotic Pest Plant in Florida." Someone in Arizona writes, "I have seen it actually lift the shingles off of roofs. It also attaches itself with the 'claw' to stucco homes and walls and when you try to remove it the stucco comes off with it!"

You can read more comments aboutn it, pro and con, at http://davesgarden.com/pf/go/1769/index.html.

What a contrast those words are to our pretty, unobtrusive vines draping themselves so prettily on our trees, causing no trouble at all and only bringing pleasure to pollinators and people.