Pebbled pixie cup has upright, stalked reproductive structures (podetia) in the form of tiny, pale brownish or gray-green goblets. Inside the cups are circular, flattened squamules (leaflike structures that can break off and start new lichens elsewhere), which are often greener than the rest of the cup. They look almost like little, flattened eggs in a nest. The podetia are not coated with granular, mealy-looking soredia (tiny packets of lichen tissue that fall away to begin new lichens elsewhere).
Pebbled pixie cup is considered a fruticose lichen, meaning it is three-dimensional as opposed to flat or crusty. Like other cladoniform lichens (members of its genus), the thallus (main body) is a patch of pale green, scale-like squamules. Cladoniform lichens have a variety of reproductive structures, including clubs with colored tips, tiny goblets, horns, or shrubby branching structures.
A lichen is an organism that results when a fungus species and an algae species join together. Although the relationship between the fungi and algae is quite intimate and integrated, the lichen that is formed does not much resemble either of the components. Learn more about lichens on their group page.
Similar species
Missouri has about 37 species in genus Cladonia, most of which, at some point in their life cycle, exist as patches of rather unspectacular greenish or grayish, scalelike squamules. The various shapes, colors, and textures of the fruiting bodies are important for identification in this group. Pebbled pixie cup is not the only species that produces cup- or goblet-shaped podetia.
Mealy pixie cup (Cladonia pyxidata) is common. It is quite similar, except that the inside of the cup lacks the circular, flattened squamules. Instead, mealy pixie cup’s podetia are coated with granular soredia, so they appear mealy.
There are other Missouri pixie cup species that look quite similar, including Gray’s cup lichen (C. grayi). Specialists use chemical tests for precise identifications.
Height: The cup-shaped podetia usually only reach about ¾ inch tall. Cladoniform lichens, as they spread, may cover several square inches of substrate.
Statewide.
Habitat and Conservation
Mealy pixie cup grows on soil. It usually occurs on mildly acidic soils over rocks such as sandstone or granite, sometimes over wood. This species is found worldwide.
Fruticose lichens are some of the first to disappear when a natural habitat is disrupted. They are also sensitive to pollution.
Life Cycle
Lichens can reproduce vegetatively or sexually. Vegetative (asexual) reproduction occurs when a piece of a lichen’s thallus (main body) breaks away and begins growing independently elsewhere.
- The thallus of cladonia species typically looks like a patch of green scale-like structures (squamules) covering a small area of substrate, much like a little carpet of moss. These may easily be dislodged and moved elsewhere.
- The “pebbles” attached to the cup and stalks of pebbled pixie cup are also squamules. These can break free and become new lichens elsewhere.
The fungal component of a lichen can reproduce sexually, in the same manner as other fungi: spores are created as the result of a fusion of gametes (sperm and ova) that occurs in reproductive structures of the fungus. The spores develop in, and are released from, a mushroom-like structure.
- In the case of pebbled pixie cup, these structures look something like the podetia of a lichen called brown cap (or turban lichen, C. peziziformis): upright stalks bearing ball-like, spore-shedding, brown knobs. In this case, they form around the cup rims.
Human Connections
Pebbled pixie cup is a joy to any photographer with a macro lens.
The Dutch graphic artist M. C. Escher created illustrations of geometrically impossible objects, such as infinite staircases, reflections on curved surfaces, and other mind-boggling subjects. In his famous piece “Waterfall,” he carefully drew fruticose lichens, with their branching knobby podetia and pixie goblets, as the trees and shrubs in his imaginary landscape.
Ecosystem Connections
Soil-living lichens are important stabilizers, preventing soil from being washed away by rain or blown by the wind.
Pebbled pixie cup and other lichens and mosses that live at the bases of rotting logs tend to retain moisture, and they trap and collect soil and organic detritus, which encourages the decomposition of the wood.
Mosses, liverworts, hornworts, and lichens seem rather similar, but these organisms are in very different groups. Mosses, liverworts, and hornworts are small, low plants usually found in damp habitats. Unlike more familiar plants, they lack veinlike structures and do not produce flowers or seeds — instead, they produce spores. Meanwhile, lichens are not plants at all: they are a collection of different fungi that have photosynthetic algae living within their tissues.