The widely distributed genus is represented in
Eurasia, North Africa, Central America, western North America, and Australia. Species of
Lobothallia are overwhelmingly
saxicolous, occupying exposed faces of
siliceous or
calcareous bedrock ranging from low‑elevation
steppe outcrops (roughly 200 m elevation) to high‑
montane belts above 2,600 m. The genus is characteristically northern‑hemispheric, with its greatest diversity recorded in the semi‑arid mountains of
Central Asia—especially the
Altai system where 12 taxa occur—and in the
Mediterranean–Alpine arc; by contrast, only five species reach
Fennoscandia and the
Urals, and very few extend into boreal substrates beyond 50° N.
Substratum specificity is broad in
Lobothallia: some taxa favour basic
limestones, others siliceous
schists,
gneiss or
serpentinite, and several tolerate heavily weathered desert
sandstones. Thalli are highly adapted to
xeric microclimates—lobes in many species are thick, and tightly , reducing water loss under intense
insolation—yet a few in the genus exploit very different
niches. The freshwater specialist
L. hydrocharis forms extensive placodioid crusts in the
splash zone of shaded mountain streams on
Sardinia, where it structures a distinctive
rheophytic lichen
community rich in
parasitic and epilichenic interactions; true submersion is avoided, but thalli are periodically inundated by water. At the opposite moisture extreme, several Asian members (e.g.
L. brachyloba and
L. zogtii) inhabit fully insolated desert pavements where summer surface temperatures exceed . Ecological
plasticity also includes a transient
lichenicolous (lichen-dwelling) phase:
L. epiadelpha initiates development on the thalli of
Circinaria maculata before overgrowing the
host and becoming free‑living, while certain
chemotypes of
L. radiosa begin as facultative parasites on
Aspicilia (in the loose sense) Recent discoveries have broadened the known range of the genus into the
Himalayas and
Hindu Kush. Four species new to science—
L. elobulata,
L. iqbalii,
L. pakistanica and
L. pulvinata—were collected on crystalline blocks and thin soil veneers between in northern Pakistan, demonstrating that continental Asian lineages extend well into
subtropical montane belts. In the neighbouring
Margalla Hills,
L. densipruinosa colonises sun‑facing
conglomerate ledges at roughly 900 m elevation, its dark‑olive discs protected by a dense cortical pruina. China has yielded parallel novelties—
L. crenulata,
L. lobulata and
L. subdiffracta var.
rimosa—which, together with previously known taxa, form a well‑supported eastern Asian clade growing on
granitic ridges between 1,500 m and 2,400 m. ==Species==