(Hamelia honors naturalist Henri L. DuHamel du Monceau. Patens means spreading.)
Rubiaceae (Coffee Family)
Today John’s and my Kiplinger activity centered on photo equipment rather than exploration, making this a good occasion for Firebush. This colorful, drug-bearing shrub or small tree will ring bells with gardeners beyond those dedicated to native species.
As with most species that slip into mainstream gardening, Firebush over many years has wandered at the hand of humans around and far beyond its broad range from South America to Florida, divvied up into cultivars in far-flung nurseries, and redistributed willy nilly. Its garden history is as willy as South Africa and as nilly as China.
My first encounter with Firebush was in the Caribbean, not Florida. This sort of mixed up globe-trotting pattern is obviously standard for any given garden species. I’m going to leave its cultivation to the innumerable websites concerned with growing stuff. To summarize the fine points of cultivating Firebush: plant it, go away.
Or let the birds plant it for you, dispersing seeds from the pea-sized berries. As is true of many species, the fruits mature through a red phase, then black, the two colors often clustered close together. The plant world is rife with red and black juxtaposed as an attractant color combo for birds. If you think about it and watch, you find red and black together in seeds, fruits, and flowers.
Let’s go a little more obscure into the secret life of Hamelia. Firebush belongs to the Coffee Family, and like its kin, the shrub has paired leaves (or leaves whorled in 3’s) with a triangular flap called a stipule on the stem between the leaf bases. Many plants have stipules, but that triangle between the leaf bases is a Coffee Family specialty. When the twig is young, those triangular flap stipules clasp the baby stem tip before the leaves grow.
This will help. Picture the boy’s head as the stem bud. The triangular sides to his hat are stipules. CLICK
In many Coffees, the stipules hide a palisade of brown micro-teeth called colleters. The colleter secretions presumably feed protective ants, and/or protectively varnish the young bud tip under the stipular hat.
Oddly though, in Firebush the colleters are either missing or too inconspicuous for me to find. Instead, the Firebush stipules have a wet-looking glossy inner surface sealed tightly against tender stem tip. As the tip elongates, the stipules remain on the side of the lengthening stem awhile, eventually to wither and drop.
The protective mechanisms get weirder. Many unrelated plants develop microscopic needle-shaped crystals called raphides inside their cells. Did you every carry an armload of prunings to the compost heap, only to suffer a burning sensation on your exposed forearm? Might be those little needles doing their job. For decades, I (and many others) assumed the raphides to work merely by pricking the flesh, and then maybe melting into irritating acid. But no…wrong…here is yet another example of the newly emerging complexities of the green world.
Biologist Kataro Konno and collaborators in 2014 documented the ability of raphide crystals to inject protein-destroying enzymes when they penetrate. They give the victim a toxic shot, or a thousand of them! More precisely, the tiny pricks punch holes in cell membranes, allowing the toxic enzyme associated with the raphides to enter the victim’s cells. Punji sticks.
Flip over a leaf and look at the corners where the side veins join the main vein. With a magnifying glass you can spot kinky white hair tufts. Those nests, called domatia, presumably house predatory mites on duty defending the foliage from leaf-bothering mites.
And speaking of mites, Firebush is a key player in research concerned with flower mites catching an inter-blossom lift from pollinating hummingbirds. (Firebush benefits from many pollinators, including butterflies, especially where hummingbirds are scarce. In its truly tropical range Firebush seemingly depends mostly on hummingbirds for “the birds and the bees.”) Flower mites are parasites able to steal pollen and nectar from the blossoms they invade. Bad news for Firebush! In some studies, those microscopic arachno-rascals have reduced the pollen and nectar substantially. They come, they raid, and then fortified on pilfered booty they reproduce, only then to hop into a hummingbird’s nostrils airborne to the next bush.
Extra notes for inquiring minds…
For taxonomy within the species, written by botanist, Dr. Thomas Elias, who revised Hamelia back in the 70s and then revisted Hamelia patens as a cultivated complex far more recently. CLICK
Persons interested in more depth on the hitch-hiking mites, CLICK
Penetrating article on the raphide needle effect: CLICKITY CLICK