Usnea substerilis

	*Usnea substerilis* Motyka


	Nomenclatural data
	Wydaw. Muz. Slask. Katowic. 3(2): 24 (1930).—Usnea sorediifera Motyka, Wydaw. Muz. Slask. Katowic. 3(2): 24 (1930), nom. illeg., non Usnea sorediifera (Arnold) Lynge (1921).—Usnea stuppea (Räsänen) Motyka
	Morphology
	For a detailed description, see Halonen et al. (1998, 1999) and Clerc (2007). Thallus shrubby, usually short, richly branched; branching mainly anisotomic-dichotomous; base pale to blackened; branches of uneven thickness, may be irregularly deformed, swollen and foveolate, with annular cracks which may have white medullary rings; fibrils present, sometimes abundant also terminally; isidiomorphs short, present at least on young soralia (and abraded on mature soralia); papillae numerous; soralia irregular, slightly tuberculate to slightly excavate, with granulose soredia. Cortex thin; medulla variable in thickness and density.
	Medullary chemistry
	(1) the main chemotype contains salazinic acid (K+ red, Pd+ yellow to orange) with different accessory substances (protocetraric, barbatic, 4-O-demethylbarbatic acids); (2) chemotype without medullary compounds (K–, Pd–) is also known (Halonen et al. 1998). In Estonia both chemotypes are recorded (n=6 and n=4, respectively), chemotype (1) is prevailing (Tõrra & Randlane 2007).
	Remarks
	Distinction from closely related taxa see under U. diplotypus.
Click on images to see more!	Ecology and distribution
	Europe (map legend) Corticolous both on coniferous and on deciduous trees. Reported in Europe: Austria, Bulgaria, Estonia, Finland, Germany, Italy, Latvia, Lithuania, Norway, Poland, Romania, Russia, Slovakia, Spain, Sweden, Switzerland, Ukraine. Estonia Grows mainly on deciduous trees (on Betula 17% of examined specimens, on other deciduous trees 33%); conifers are inhabited less often (Picea 17%, Pinus 8%, other tree species 15%) than by most Usnea species. Rather rare in Estonia (10 specimens), found scattered in all regions of Estonia (Tõrra & Randlane 2007).

Species pages available articulata \| barbata \| cavernosa \| ceratina \| chaetophora \| cornuta \| dasaea \| dasypoga \| diplotypus \| esperantiana \| flammea \| flavocardia \| florida \| fragilescens \| fulvoreagens \| glabrata \| glabrescens \| hirta \| intermedia \| lapponica \| longissima \| mutabilis \| praetervisa \| rubicunda \| schadenbergiana \| silesiaca \| subcornuta \| subfloridana \| subscabrosa \| substerilis \| wasmuthii