Argemone mexicana

(Argemone is an ancient Greek name for a similar plant.)

Papaveraceae, the Poppy Family

The trouble with species and actors known for one thing is that they become typecast at the expense of “other things.”  So it is for the biochemical factory known as Mexican Poppy. You’d be challenged to find a plant with a thicker pharmacological portfolio, but little else is known about it.    Despite the deficiency, let’s explore the “other things” first.

Native to Florida and Tropical America, Mexican Poppy is a colorful and bioactive invasive annual in the warm-climate Old World, prominently so in Africa and India, where it has woven itself into local cultures.   Its splendid yellow flowers and white-patterned leaves plus dubious medicinal benefits have created a market for the seeds.

The plant loves uncrowded disturbed situations, popping up socially distanced on bare soil.  Its basic strategy is fast growth to seed production in nasty sun-baked places free of competitors.   Down goes a quick taproot and up come those gorgeous flowers and prickly pods before neighbors crowd in.  And should that threaten, well, Mexican Poppy can poison surrounding plants.   This diminishes its popularity in agricultural fields, except sometimes for suppressing other weeds.   Herbivores tend to take a raincheck, since the leaves are painfully prickly and the plant is a cauldron of bioactive chemicals, many of them in yellow sticky sap.

Botanist M. Kaul studied the floral biology in India in the 1960s.  The vivid showiness of the blossoms may be largely wasted, given that they are in large part self-pollinating, no big surprise in a pioneering weed.  Pollen releases before the flowers open, although visiting insects probably add cross-pollination when the flowers are open.   Oddly, the flowers have a second, post-opening opportunity for self-pollination.  While open the petals collect pollen like sugar on a spoon, then when the flowers close the rising petals lift the pollen up to the pollen-receiving stigma.  Reproductive assurance!    Dr. Kaul’s sketch of what happens is below:

An aspect of the pollination that I’ve never encountered before, perhaps revealing bone-headed ignorance, is that pollen fertility increases at the height of the flowering season.  This pattern was consistent across many flowers at many localities in India.  Could it be that during the off-season more reliance on self-pollination allows reliance on less-fertile pollen, with an investment in the “good stuff” saved for a precious peak-season insect agents?  Or a boring alternative is that poor weather in the off-season interferes with pollen quality. This should be checked out here in native Florida, and I might try.

The seeds look like mustard seeds and similarly, contain oil.   They have been mixed as a cheap extender to mustard seeds, with fatal consequences when used in cooking.  The oil serves less dangerously as lamp fuel and has been investigated as a source of biodiesel growable where other crops won’t grow.

Name any human medical need from malaria to male contraception.   Mexican Poppy has been applied for or suspected as potentially useful for a hundred problems.  (Forget trying anything—it is dangerously toxic.)  Among the more prevalent applications are to cure worms, to fight leprosy, and  to counter skin conditions.   The ancient Greeks used related species to treat cataracts.  Morphine comes from poppies. Does Mexican Poppy contain morphine?  Not to my knowledge, but it does contains chemicals animal-tested for morphine-withdrawal.  Modern medicine is perpetually interested in cell-killing (cytotoxic) compounds to treat tumors.   A wart is a (benign) tumor, and historical uses of Mexican Poppy to kill warts signals potentially useful cytotoxicity.

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