Today John and I started a new old project….to update and upgrade the photos in the old Palm Beach State College Guide to South Florida Weeds.

We soon met a Southern Leopard Frog happy to duck amphibian decline.

Portrait today by John Bradford.

The frog’s fancy-pants pattern brought to mind the patterned leaves encountered sporadically in weeds and other plants.  Setting aside variegation caused by mutations and by viruses, what I’m thinking of now are species with white veins.

In houseplants

In orchids

And so forth and what-have-you.  Compare this Milk Thistle to the similar but unrelated Mexican Poppy below:

Why would unrelated plant species do the same odd thing?  Gotta be an adaptive benefit.    The proposed benefit I like, not original with me, is that maybe leaves with white veins are mimicking the streakings and vein discolorations of senescent, nutrient-deficient, or infected leaves.  Such leaves presumably offer poor nutrition to pests and may be unpromising nurseries for buggy eggs.   Go bother a different “healthy” plant!   Of course  this is pure speculation.

Sick leaf.

The most striking local white-veiner is the Mexican Poppy, Argemone mexicana, which is arguably native here.     This prickly beauty has spread itself around the world in agricultural seed, and maybe sometimes as a garden flower or oil-producing and medicinal plant.

Mexican Poppy

The traditional medicinal uses are many, and are the ancient roots of its name, probably from Greek argemos for cataract, as in the eye.  But beware, in India over-exposure to its many toxins has caused plant-induced dropsy (aka heart failure).   The seeds give up oil for lamps and for lubrication.

White veins, as promised.

Being a poppy, does Mexican Poppy have psychotropic effects, as in opium poppies?    Probably,  to a limited and poorly documented point, but to be repetitive and uber-emphatic the yellow sap is dangerously toxic, laden with alkaloids, and AT LEAST damaging to the heart it seems.  So forget it.

For a weed taking over the world, MP sure is fussy about appearances in South Florida.  I can’t recall encountering it in a wild area.   The species likes agriculture.   The bristly capsule drops seeds all over the ground.   They lie dormant then in the seedbank until cows or plows rouse them to sprout, often in unison.  You know, fields of poppies.