Physcia stellaris is a species of lichen. It is pale grey, but darker in the centre, and lacks isidia, lobules, soredia and pruina.It tests positive K+ yellow upper cortex with a 10% potassium hydroxide solution. In North America, it is known colloquially as the fringed rosette lichen.
Letharia vulpina, commonly known as the wolf lichen, is a fruticose lichenized species of fungus in the family Parmeliaceae. It is bright yellow-green, shrubby and highly branched, and grows on the bark of living and dead conifers in parts of western and continental Europe and the Pacific Northwest and northern Rocky Mountains of North America. This species is somewhat toxic to mammals due to the yellow pigment vulpinic acid, and has been used historically as a poison for wolves and foxes. It has also been used traditionally by many native North American ethnic groups as a pigment source for dyes and paints.
Xanthoparmelia chlorochroa, known as the tumbleweed shield lichen or ground lichen, is a foliose lichen in the Parmeliaceae family. It is not fixed to a substrate, and blows around in the wind from location to location.
Cladonia furcata or the many-forked cup lichen is a species of cup lichen in the family Cladoniaceae. It has an intermediate to tolerant air pollution sensitivity. Extracts of this species have been shown to kill leukemia cells in vitro, and may have possible value in the treatment of cancer.
Hypogymnia is a genus of foliose lichens in the family Parmeliaceae. They are commonly known as tube lichens, bone lichens, or pillow lichens. Most species lack rhizines that are otherwise common in members of the Parmeliaceae, and have swollen lobes that are usually hollow. Other common characteristics are relatively small spores and the presence of physodic acid and related lichen products. The lichens usually grow on the bark and wood of coniferous trees.
Menegazzia terebrata is a species of foliose lichen found scattered across many continents, including North America, South America, Europe, Africa, and Asia.
Pilophorus acicularis, commonly known as the nail lichen or the devil's matchstick lichen, is a species of matchstick lichen in the family Cladoniaceae.
A foliose lichen is a lichen with flat, leaf-like lobes, which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common growth forms of lichens. It typically has distinct upper and lower surfaces, each of which is usually covered with a cortex; some, however, lack a lower cortex. The photobiont layer lies just below the upper cortex. Where present, the lower cortex is usually dark, but occasionally white. Foliose lichens are attached to their substrate either by hyphae extending from the cortex or medulla, or by root-like structures called rhizines. The latter, which are found only in foliose lichens, come in a variety of shapes, the specifics of which can aid in species identification. Some foliose lichens attach only at a single stout peg called a holdfast, typically located near the lichen's centre. Lichens with this structure are called "umbilicate". In general, medium to large epiphytic foliose lichens are moderately sensitive to air pollution, while smaller or ground-dwelling foliose lichens are more tolerant. The term "foliose" derives from the Latin word foliosus, meaning "leafy".
Lichens are symbiotic organisms made up of multiple species: a fungus, one or more photobionts and sometimes a yeast. They are regularly grouped by their external appearance – a characteristic known as their growth form. This form, which is based on the appearance of vegetative part of the lichen, varies depending on the species and the environmental conditions it faces. Those who study lichens (lichenologists) have described a dozen of these forms: areolate, byssoid, calicioid, cladoniform, crustose, filamentous, foliose, fruticose, gelatinous, leprose, placoidioid and squamulose. Traditionally, crustose (flat), foliose (leafy) and fruticose (shrubby) are considered to be the three main forms. In addition to these more formalised, traditional growth types, there are a handful of informal types named for their resemblance to the lichens of specific genera. These include alectorioid, catapyrenioid, cetrarioid, hypogymnioid, parmelioid and usneoid.
Stephen Sharnoff is a photographer, especially of botanical and lichen subjects. He specializes in close-up botanical color work. He is also a research associate at the University and Jepson Herbaria of the University of California, Berkeley and a past associate of the Missouri Botanical Garden.
A spot test in lichenology is a spot analysis used to help identify lichens. It is performed by placing a drop of a chemical on different parts of the lichen and noting the colour change associated with application of the chemical. The tests are routinely encountered in dichotomous keys for lichen species, and they take advantage of the wide array of lichen products produced by lichens and their uniqueness among taxa. As such, spot tests reveal the presence or absence of chemicals in various parts of a lichen. They were first proposed by the botanist William Nylander in 1866.
Lepraria pacifica, the Pacific dust lichen, is a whitish-blue-green leprose crustose lichen that grows on its substrate like patches of granular, caked-up, mealy dust grains. Like other members of the Lepraria genus, it only reproduces asexually.
Alectoria sarmentosa is a long-lived, perennial witch's-hair lichen. It is also sometimes classified as a fungus. It is a light greenish colored and fruticose or bushy bodied. This epiphytic lichen belongs to the family Parmeliaceae and the suborder Lecanorineae, which includes six similar species. A. sarmentosa grows draped or strung over conifer tree limbs and deciduous shrub branches in Northern temperate rainforest. This lichen favors mature and old growth, wet conifer and hardwood forests with clean air. A. sarmentosa is sensitive to air pollution and used for air quality monitoring. Areas required by A. sarmentosa are found in northern and southern temperate zones and receive high rainfall. This lichen is commonly found in transitional areas between valley and mountainous forests, but usually avoiding the immediate coast.
A podetium is the upright secondary thallus in Cladonia lichens. It is a hollow stalk extending from the primary thallus. Podetia can be pointed stalks, club like, cupped, or branched in shape and may or may not contain the ascocarp, the fruiting body, of the lichen. It is not considered part of the primary thallus as it is a fruiting structure for reproduction.
Bruce Pettit McCune is an American lichenologist, botanist, plant ecologist, and software developer for analysis of ecological data.
Punctelia rudecta, commonly known as the rough speckled shield or the speckleback lichen, is a North American species of foliose lichen in the family Parmeliaceae. This species can be readily identified by the light color of the thallus underside, the relatively large lobes at the edges of the thallus, and the tiny white pores present on the top of the thallus that are characteristic of the genus Punctelia. The lichen is quite abundant and widespread in the eastern and southeastern United States, although it also occurs in Canada and northern Mexico, but is less common in these regions. The lichen usually grows on bark, and less commonly on shaded rocks. There are several lookalike Punctelia species; these can often be distinguished from P. rudecta by differences in distribution or in the nature of the reproductive structures present on the thallus.
Hypogymnia krogiae, commonly known as the freckled tube lichen, is a species of foliose lichen in the family Parmeliaceae. Found in North America, it was described as a new species in 1973 by Karl Ohlsson. The type specimen was collected near Cheat Bridge, West Virginia by Mason Hale in 1956.
Letharia columbiana is a common lichen in subalpine forests, particularly in the Pacific Northwest of the United States, and parts of Canada. It is in the family Parmeliaceae, and the genus Letharia. Its characteristics include a bright citron color, “brown-eyes”, and rounded, irregular branches. Though previously believed to lump together several lineages such as Letharia gracilis and others, there now exists more specific characteristics to identify the species. This lichen grows on the bark of conifers a couple inches tall. L. Columbiana’s cousin, Letharia vulpina (common name wolf lichen), has similar geographical distribution and morphological features, with the major difference being the “brown-eyes” of L. columbiana.
Candelaria concolor, commonly known as the candleflame lichen or the lemon lichen, is an ascomycete of the genus Candelaria. It is a small foliose lichen dispersed globally.
Solorina crocea, commonly known as the orange chocolate chip lichen, is a species of terricolous (ground-dwelling) and foliose (leafy) lichen in the family Peltigeraceae. The lichen, which was first formally described by Carl Linnaeus in 1753, has an arctic–alpine and circumpolar distribution and occurs in Asia, Europe, North America, and New Zealand. It generally grows on the bare ground in sandy soils, often in moist soil near snow patches or seepage areas. Although several forms and varieties of the lichen have been proposed in its history, these are not considered to have any independent taxonomic significance.
