“The Redcoats are coming, the Redcoats are coming.”

This isn’t a flashback to 1775, although I am writing on the historic Patriots Day holiday. And, no, you don’t have to hear of the midnight ride of Paul Revere. I will save you from that poetic prose, but will tell you of the Redcoats that have invaded the woodlands.

These Brits are small and subtle and won’t scare off even the weakest patriot. British soldier lichens are gathering their troops in the woods. These lichens are found in decaying woods, mossy logs, rotting trees and stump bases. They are small, only growing about one inch high, and are usually found in groups, rather than singly. Their identity is assured when they tip their brightly-colored hat.

British soldier lichens make us see red. Not anger, but apothecia, colors the rot red. Apothecia are the roundish red tips of the British soldier lichen and are the most obvious part of this small lichen. They are the reproductive structure holding the lichen’s spores, and it can take at least four years before these structures can produce spores. Spores are only one way that lichens can reproduce; they can also multiply vegetatively by breaking off and creating new lichens.

To continue with lichen morphology, note the stalk-like part of this fruiticose, or fruiting lichen, called the thallus. Fruiticose describes the type or form of lichen that includes British soldier and other three-dimensional lichens. Alternate growth forms of lichen include crustose (think of a crust of lichen flush with its substrate), or foliose (flaky lichen that can be peeled or pried off).

Lichens are a bit of a mystery to most of us. They are neither animal, plant, nor fungus, but a quirky combination of the latter two. Lichens are part algae and part fungus, but come together to create a new and unique organism, not related to its two initial parts. The algae provides the food via photosynthesis, while the fungal component provides moisture and structure. In the case of lichens, two is better than one.

An easy and fun way to remember basic lichen structure is this: “Anna Algae took a lichen to Fred Fungus and their marriage is often on the rocks.” Lichens are unusual in that they can survive on rocks and other inhospitable surfaces. They function in these cases as a pioneer species, which means that they break down, or decompose their substrate. This helps over the long term in the eventual creation of soil and a more welcoming surface for a new generation of plants.

The scientific name of British soldier lichen is Cladonia cristatella. Translated, this name means small crested and sprouting, which describes its upright lifestyle. Matchstick moss is another alias, though one that is inaccurate since lichens are not moss.

Like Paul Revere, you must be observant to see these little lichens standing at attention in the woods. Whether we are ready or not, here they come. Woodland soldiers uniform up and ready the troops!

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.