Howker Ridge • Plant

Field Notes

• A fruticose (branching) lichen that forms upright hollow tubes with flaring cup-shaped tops. The **podetia** (cup stalks) are 0.5–1.5 cm tall and 2–6 mm wide at the top, tapering toward the base. They are pale green-gray and covered in coarse granules (soredia) and often small scale-like areoles. The rim of each cup may be even or have a few small tooth-like lobules. The interior of the cup is typically granular as well. The base of the lichen (the primary thallus) consists of small, flat to somewhat curled lobes (about 2–4 mm across) that are gray-green on top and white below, pressed against the substrate. These basal squamules provide nourishment to the fungus via their algae and help attach the lichen. Pixie-cup lichen may produce sexual reproductive structures (apothecia), but in this species they are not showy – they would appear as tiny brown discs on the cup edges (often the cups remain sterile, reproducing mainly by soredia). The entire organism is fairly brittle; pieces can break off and form new colonies (a form of vegetative reproduction). The lichen’s cross-section (if you could slice the cup) shows distinct layers: an outer cortex, the algal layer beneath, and a medulla (fungal layer) inside – but these details require magnification. From above, especially when moist, the cups have a greenish cast due to the algae; in dry conditions, the lichen looks grayer. It’s often found intermingled with mosses, so it might have fragments of moss or organic matter stuck to it.
• Pixie-cup Lichen contributes to the slow breakdown of wood and the creation of soil. Lichens like this can colonize bare wood or soil surfaces, and by secreting certain acids they help erode their substrate – for example, aiding in decaying a stump into soil over years. They also trap moisture and provide a foothold for other small organisms. These lichens are part of forest nutrient cycles: when they eventually die, they add organic matter and minerals (accumulated from rainfall and dust) to the soil. Pixie-cups often grow intermingled with mosses (as seen in the photos), and likely benefit from the moisture the moss holds. They, in turn, may protect the moss from drying out by shading the surface slightly. As a symbiotic organism, the alga in the lichen photosynthesizes and provides food for the fungus, while the fungus provides structure and protection – an arrangement that allows pixie-cup lichens to live in nutrient-poor niches. A few creatures utilize these lichens: some snails and slugs will graze on lichens including Cladonia (the soft tissues and algae are a source of nutrients), and certain mites or springtails might feed on the fungal or algal components. Lichen-feeding insects (like some Lepidoptera larvae) might occasionally include Cladonia in their diet, though pixie-cups are small. There are also specialized lichenicolous fungi (fungi that parasitize lichens) that can infect pixie-cup lichens, though this is not easily observed without a lens. In terms of succession, pixie-cup lichen is somewhat of a transitional colonizer – it often appears after mosses on a dead log and will flourish until the wood becomes too decomposed and soil accumulates, at which point higher plants or thicker moss might take over. Cladonias are also indicators of good air quality; they do not thrive in polluted air (sulfur dioxide, for instance, can kill them). So healthy populations of pixie-cup lichen in a forest suggest a relatively unpolluted environment. On a whimsical note, their fairy-goblet appearance has led to folklore that they are used by pixies or forest fairies for drinking cups, which, while fanciful, reflects the charm they add to the forest micro-landscape. They create a **miniature ecosystem** on each stump, complete with its own cycle of growth and decay, contributing to the forest’s diversity at a tiny scale.
• Pixie-cup lichens are common and widespread across the Northern Hemisphere. Cladonia pyxidata (and its close relatives in the pixie-cup complex) are considered globally secure (G5). In New Hampshire and the White Mountains, they are frequently found in appropriate habitats – any decaying log in a moist forest might host them. There are no known threats specific to this species; their health is tied largely to air quality and habitat availability. As long as forests with rotting wood exist and the air remains relatively clean, pixie-cup lichens will persist. They are not subject to collection pressure (occasionally hobbyists or educators might gather a piece to show students, but this has negligible impact). Environmental changes that could affect them include severe air pollution or drastic changes in forest moisture (e.g., extreme droughts may cause local die-back, but lichens can often rebound or survive dormant). Because they rely on a stable partnership between fungus and alga, they are sensitive to disruptions like acidic pollution or heavy metals, which can damage the algal cells. Historically, industrial pollution in parts of Europe caused declines in sensitive lichens, but the White Mountains, being largely rural, haven’t seen such lichen losses. Indeed, pixie-cup lichens are still flourishing on logs from valley floors up to subalpine elevations (though in alpine areas the Cladonia genus tends to form reindeer lichens rather than cups). Conservation-wise, they don’t require direct intervention; protecting forest habitats and maintaining air quality suffices. They serve as reminders of the importance of **Leave No Trace** – a heavy boot scrape on a mossy log can obliterate decades of slow lichen growth in an instant. However, given time and good conditions, they’ll recolonize. In summary, pixie-cup lichens are not endangered or rare; they are small but resilient denizens of the forest, continuing their quiet work of turning wood into soil, one tiny cup at a time.

Photo Credits

(c) Nathan Sobol / NH48pics.com