(Upload on November 22 2014) [ 日本語 | English ]

Lichens (地衣類)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Consortium (共同体):
fungi + algae → consortium
an association, or 'living together', of organisms, ranging from epiphytism without obvious interdependence to symbiosis with definite mutual depencencies between the partners


Crustose lichen (固着地衣, 痂状地衣)
crust-like lichens that may be buried in tree bark, or even between the crystals of rocks
Fruticose lichen (樹状地衣, 樹枝状地衣)
miniature shrub-like lichens.- one lichen of this type is the famous "reindeer moss" of Lapland
Foliose lichen (葉状地衣)
flat leaf-like lichens
Squamulose lichens (鱗片状地衣)

scaly lichens made of numerous small rounded lobes, intermediate between foliose and crustose lichens


Inner structure

Lichens are composed of a number of layers. The outer layer (farthest from the substrate) is known as the cortex (皮層) and is composed of fungal cells. The next layer, algal layer (藻類層) or gonidial layer (ゴニディア層), is dominated by algal cells in a matrix of fungal threads that hold them in place, close to the surface. The third layer is the medulla (髄層), which is largely made up of fungal cells. In crustose lichens, this layer is directly connected to the substrate, but the other two groups differ: foliose lichens have another layer, the lower cortex (下皮層), and are attached to the substrate by means of rhizine (偽根), hair-like strands; in fruticose lichens, the cortex and algal layer are repeated below the medulla. The entire structure is called a lichen body (地衣体) or thallus.
crustose lichen
Upper cortex

Algal layer

fruticose lichen
Upper cortex

Algal layer


Algal layer

Lower cortex
foliose lichen
Upper cortex

Algal layer


Lower cortex

crustose lichenfruticose lichenfoliose lichen

Chemical components (地衣成分)

Shikimic acid origin (シキミ酸経路)
Chemical commponent Orcin system β-orcin system
Olivetolic acid
shikimic acid
shikimic acid
Despidone Pysodic acid
shikimic acid

shikimic acid

Taxonomy (分類)

classified by the fungal component
  • Zahlbruckner A. 1926. Lichens. In: Engler & Prantl: Die naturlichen Pflanzenfamilien 8 Bd., 2 Aufl. Verlag Wilhelm Engelmann, Leipzig. pp. 61-270

Photobiont (共生藻類)

Greenfilamentous /placoidCephaleuros, Leptosira, Phycopettis, Pseudopleurococcus
monocellular/short, irregular filamentousChlorella, Chlorosarcina, Cocobotrys, Coccomyxa, Gleocystis, Hyalococcus, Myrmecia, Protococcus, Pseudochlorella, Stichococcus, Trebouxia, Trochiscia
Blue-greenfilamentousCalothrix, Dichothrix, Hyella, Nostoc, Scytonema
colonialChroococcus, Gloeocapsa


Indicator species of pollution
Species promoting chemical weathering
Sometiems pioneer species along successional sere