It’s hard to find, but yes Miami, mistletoe grows here

Friday, December 16, 2016

Kenenth Setzer Fairchild Tropical Botanic Garden

As published in the Miami Herald, DECEMBER 16, 2016 7:00 AM

A healthy growth of mistletoe on an otherwise almost bare mahogany. KENNETH SETZER Fairchild Tropical Botanic Garden

Classic European mistletoe — the species most commonly associated with Christmas, ancient Celts, and kissing — does not grow in our region. However there are mistletoe species in North America, and we actually have our very own native Florida species of mistletoe to kiss beneath.

Phoradendron rubrum, the mahogany mistletoe, is exceedingly rare. Its host, West Indian mahogany (Swietenia mahagoni), is commonly used in landscaping, but is listed as threatened in the wild. Mahogany mistletoe is unlikely to be found on planted trees, only those that grow in the wild.

So perusing Fairchild’s plant list recently, I was pretty stunned to find mahogany mistletoe included. I had the impression it survived only on a few Florida Keys. Off I trudged into the wilds of the Garden’s lowlands and the Keys Coastal Habitat. Many visitors don’t realize they are welcome to explore our unpaved, less manicured, lowlands trails, where there are a lot of treasures to discover.

I found mahoganies, and kept looking up and up, referring to a photo on my phone. I spotted translucent white berries among mahogany branches. This must be it! Wrong. Our conservation experts set me straight: It was snowberry or milkberry, Chiococca alba. They then took me out to find the real thing.

I would never have spotted them on my own. But there they were, little sprigs of green. Part of mistletoe’s intrigue may come from the fact that in winter, with its host tree bare, the mistletoe remains green. South Florida’s mahoganies are at their northern limit here, and consequently are semi-deciduous, so this time of year I could see the mistletoe clearly. Although it’s a different plant, its appearance is similar to European mistletoe.

Mistletoe has come to refer to many different parasitic plants. The European plant is Viscum album, while the Eastern mistletoe native to North America is Phoradendron leucarpum, in separate genera. There are even mistletoes in different families. Mistletoe, then, is more of a way of life; a parasitic one at least. Ours produces pale orange berries that are consumed by birds and spread when the bird deposits the undigested seed on a branch.

The seedling eventually penetrates the vascular system of its host and takes advantage of the tree’s water and nutrients. The mistletoe does obtain some nutrition on its own, through photosynthesis, making it only a hemiparasite. Fairchild’s were introduced years ago by conservation staff and have survived. It may seem odd to introduce a parasite, but it has its place.

Its etymology is a lot less clear than its lifestyle. There are lots of conflicting linguistic tales, but the best I can get from the Oxford English Dictionary is that mistle meant mistletoe or basil, and tan meant twig, and changing noun genders led to something more like -toe. I have a suspicion the first part is related to German mist, but it’s pure speculation that only time travel is likely to confirm.

But don’t let this take away the romantic notions of standing under the mistletoe. While mistletoe has been associated with Christmas decoration and kissing rituals only since about the 18th century, Pliny the Elder a couple millennia ago described its use in Druidic rituals, so mistletoe has been special to people for thousands of years.

While you are unlikely to run across mahogany mistletoe, it’s satisfying to know it is out there still, feeding birds and fueling imaginations.

Mahogany mistletoe’s leaves are thicker and smoother than its host’s foliage.
Mahogany mistletoe’s leaves are thicker and smoother than its host’s foliage. KENNETH SETZER Fairchild Tropical Botanic Garden

Pale orange mistletoe fruit, barely visible.
Pale orange mistletoe fruit, barely visible. KENNETH SETZER Fairchild Tropical Botanic Garden