Erythrina herbacea

Fabaceae

Erythrina herbacea is sometimes called “Devil in the Bush.”   I’ve heard this explained as being based on the plant’s devilish thorns, but a scarlet flower cluster hiding in the undergrowth looks like a devil in the bush to me.    This perennial, or shrub, or small tree is in flower now.

You’d think its flowering period and the presence of hummingbirds who pollinate it should be matched.    So let’s see, a quick look at herbarium specimens from Florida shows the Erythrina blooming February-May, especially March and April.  Snowbird Hummingbirds return northward through Florida mostly February-March, matching the presence of the flowers.   The continued flowering in April and May may sound mildly mysterious, and is probably best explained by the plant’s distribution as far north as the Carolinas and near or into Oklahoma, where the late-spring flowering probably corresponds to progress of the northward migration. 

Hummingbirds need a lot of nectar, and Coral-Bean produces nectar so abundant it literally can drip from the maturing flowers, much to the delight of visiting ants and bees who do not seem to respect the exclusivity of “hummingbird” flowers.   It would be interesting—and unstudied—to know the contribution to pollination by such unofficial visitors.

The weirdest floral visitors are thrips, sometimes found partying abundantly on the flower tubes.  Why?  Not much is known about this, but there are hints.   Although thrips usually consume plant tissues, some flower thrips ingest nectar, so those nectar-drippy flowers may feed their resident thrips. That they are abundant on the red Erythrina flowers may (or may not) be significant.  Research shows thrips to be able to see red, and females of some species congregate preferentially on red flowers for mating.    It would be fun to know if those general observations apply to Coral-Bean.  My bet is on “yes.”

After pollination by a hummingbird, or however else it may occur, a big bean pod forms containing bright red seeds no doubt attractive to birds.  The pods can persist on the stems for multiple months.

The seeds and other plant parts are dangerously toxic, the poison acting similar to the curare used on poison arrows, and causing paralysis.    They have served as low-budget rat poison, and sadly to murder dogs.   Makes one wonder a bit about even worse applications?

Depending on the habitat and latitude, the plants can be perennial herbs, or shrubs, or trees.  Their massive taproot drills multiple feet down into the soil,  allowing the perennial individuals to withstand fires, floods, storms, and cold, and to live a long long time to feed many many hummingbirds.