Table 1. Main differences of the species of Xanthoparmelia pulla group studied in this paper [38], [44], [47], [59], [60].

	Characters and distribution
Species	Morphology of lobes	Isidia	Lower surface	Chemistry	Distribution
X. atroviridis	1–2 mm broad, subirregular, contiguous to imbricate	Absent	Black, moderately rhizinate, rhizines concolorous, up to 0.4 mm long.	Medulla: Hypoconstictic, hypostictic, hyposalazinic acids; Cortex: HNO3 + violet	South Africa
X. caliginosa	1–2.5 (−3.5) mm broad, subirregular, contiguous to imbricate	Sparse to crowded and areolate. Isidia erumpent, globose to cylindrical, 0.1–0.6 (−0.8) mm tall.	Dark brown to black, moderately rhizinate, rhizines more or less concolorous, up to 0.6 mm long.	Medulla: Olivetoric acid. Cortex: HNO3 + blue-green	South Africa
X. delisei	1–4 mm broad, sublinear to irregular, flat to slightly concave or convex, becoming laciniate, often imbricate and entangled	Absent	Dark brown to black, often paler near the apices, moderately to densely rhizinate, the rhizines simple and concolorous with the lower surface, to 1 mm long	Medulla: glomelliferic, glomellic, perlatolic acids; ± gyrophoric acid. Cortex: HNO3 + blue-green	Europe, Asia, Africa, Australia, Macaronesia, South America
X. fissurina	1–3 mm broad, contiguous to imbricate or entangled	Absent	Pale tan to pale brown, moderately rhizinate, rhizines concolorous, to 1 mm long	Medulla: hypostictic, hypoconstictic, hyposalazinic acids, unknown compounds. Cortex: HNO3 + blue-green	South Africa and South America
X. glabrans	0.5–3.0 mm broad, sublinear to linear-elongate, imbricate to loosely entangled.	Absent	black, dull, slightly rugulose, moderately rhizinate; rhizines black, simple or fasciculate, to 1 mm long	Medulla: alectoronic acid; ± a-collatolic and gyrophoric acids. Cortex: HNO3 + blue-green	Australia, Europe, Africa, South America, New Zealand
X. imitatrix	0.5–3.0 mm broad, sublinear to linear-elongate, imbricate to laciniate entangled, rarely developing subfruticose branches	Absent	Dark brown to black, sparsely to moderately rhizinate, rhizines simple, to 1.5 mm long	Medulla: physodic acid; ±4-O-methylphysodic and alectoronic acids. Cortex: HNO3 + blue-green	Australia, Africa, South America, New Zealand
X. lineella	0.1–0.5mm broad, linear and dichotomously branched and entangled	Absent	Black, sparsely rhizinate, rhizines concolorous, to 1 mm long	Medulla: physodic acid; Cortex: HNO3 + blue-green	South Africa
X. loxodes	(0.5-)1–3(−5) mm broad, subirregular to sublinear, contiguous to entangled.	Sparsely to densely isidiate, isidia more or less spherical and distinctly pustular, erumpent	Dark brown to black, smooth to somewhat rugulose, moderately rhizinate, rhizines concolorous, to 1 mm long	Medulla: glomelliferic, glomellic and perlatolic acids; ±gyrophoric acid. Cortex: HNO3 + blue-green	Europe, North Africa, Asia, North America, Macaronesia
X. luteonotata	(0.5-)1–3 mm broad, sublinear to irregular, discrete to imbricate, rarely developing subfruticose branches	Absent	Pale tan to pale brown, moderately to densely rhizinate, rhizines simple, to 0.5 mm long	Medulla: ± divaricatic and stenosporic acids; ± gyrophoric acid. Cortex: HNO3 + blue-green	Australia, Europe, Africa, New Zealand
X. pokornyi	1–2 mm broad, sublinear to linear, discrete to loosely imbricate or entangled	Absent	Pale tan to brown, moderately to sparsely rhizinate, rhizines concolorous or darkening, to 1 (−1.5) mm long	Medulla: stenosporic acid; ± gyrophoric and divaricatic acids. Cortex: HNO3 + blue-green	Europe, Asia
X. perrugata	1–3 (−5) mm broad, sublinear to linear-elongate, discrete to imbricate or entangled.	Absent	Dark brown to black, moderately to densely rhizinate, rhizines simple, to 1.5 mm long.	Medulla: divaricatic acid; ± stenosporic, oxostenosporic, gyrophoric, lecanoric acids. Cortex: HNO3 + blue-green	Europe, North Africa, Australia, Asia
X. pseudoglabrans	1–2.5 mm broad, subirregular to sublinear, imbricate to entangled	Absent	Black; moderately rhizinate or rhizines rather parse, concolorous with the lower surface	Medulla: alectoronic acid; ± a-collatolic acid. Cortex: HNO3 -	South Africa
X. pulla	1–3 (−5) mm broad, sublinear to linear-elongate, discrete to imbricate or entangled	Absent	Dark brown to black, moderately to densely rhizinate, rhizines simple, to 1.5 mm long	Medulla: stenosporic acid; ± divaricatic, gyrophoric, perlatolic, 4-O-demethylstenosporic acid, oxostenosporic acids. Cortex: HNO3 + blue-green	Europe, Australia, New Zealand, Africa
X. pulloides	1–2 mm broad, subirregular to sublinear, contiguous to subimbricate	Absent	Black, moderately rhizinate, rhizines concolorous, to 0.5 mm long	Medulla: constipatic and protoconstipatic acids; ± gyrophoric acid. Cortex: HNO3 + blue-green	Macaronesia, Asia
X. quintarioides	1–2.5 (−3) mm broad, strongly convex and short-flabellate, discrete but close to more or less contiguous	Absent	Tan to pale brown, sparsely to moderately rhizinate, the rhizines short and hapterate	Medulla: hypostictic, hypoconstictic, cryptostictic acids; ± hyposalazinic acid. Cortex: HNO3 + blue-green	South Africa
X. ryssolea	1–3 mm broad, linear elongate, subterete, convex.	Absent	Pale yellow-brown to red-brown, canaliculate, sparsely rhizinate, rhizines concolorous, to 0.6 mm long.	Medulla: stenosporic acid; ± gyrophoric, oxostenosporic, divaricatic acids. HNO3 + blue-green	Europe, Asia
X. squamans	1–2 mm broad, sublinear, imbricate to contiguous	Absent	Dark brown to black, moderately to sparsely rhizinate, rhizines concolorous, to 1 mm long	Medulla: hypostictic, hypoconstictic, hyposalazinic acids. HNO3 + blue-green	South Africa, South America, New Zealand
X. subhosseana	1–2 mm broad, subirregular, contiguous to slightly imbricate	Sparsely to densely isidiate. Isidia pustular, erumpent	Dark brown to black, moderately rhizinate, rhizines concolorous, to 0.6 mm long	Medulla: hypostictic, hyposalazinic, hypoconstictic acids. Cortex: HNO3 + blue-green	South Africa, North America, South America, New Zealand
X. subimitatrix	0.5–2.0 mm broad, sublinear to subirregular, discrete to subimbricate	Absent	Pale tan to brown, moderately rhizinate, rhizines simple, brown or often blackened, to 0.8 mm long	Medulla: physodic acid and alectoronic acids. Cortex: HNO3 + blue-green	South Africa, Australia.
X. subincerta	0.5–1 mm broad, flat, sublinear, more or less imbricate	Isidia cylindrical, simple or densely branched, 0.08–0.5 mm tall. Apices syncorticate	Black, moderately rhizinate, rhizines simple, black, to 0.3 mm long	Medulla: glomelliferonic acid; ± loxodellonic and glomellonic acids. Cortex: HNO3 + blue-green	Australia, South Africa
X. subprolixa	1–3 (−5) mm broad, sublinear to linear-elongate, discrete to imbricate or entangled.	Absent	Dark brown to black, often paler at apices, moderately to densely rhizinate, rhizines simple, to 1.5 mm long	Medulla: divaricatic acid; ± stenosporic, nordivaricatic acids. Cortex: HNO3 + blue-green	Australia, New Zealand
X. torulosa	1.0–3.5 mm broad, sublinear to sublirregular, imbricate; laciniae at periphery and within thallus, ± subfruticose, sublinear to elongate, 0.3–1.0 mm broad.	Absent	Black, moderately to densely rhizinate; rhizines simple or occasionally tufted, slender.	Medulla: divaricatic acid; ± nordivaricatic, stenosporic acids. Cortex: HNO3 + blue-green	Australia
X. verisidiosa	1–3 mm broad, irregular to sublinear, flat, short and rounded, contiguous to imbricate	Sparsely to densely isidiate. Isidia cylindrical, simple or becoming densely branched, 0.2–1 mm tall. Apices syncorticate	Black, moderately to sparsely rhizinate, rhizines simple, black to 0.4 mm long	Medulla: alectoronic and a-collatolic acids. Cortex: HNO3 + blue-green	Australia, New Zealand, South Africa
X. verrucella	0.5–2 mm wide, irregular to sublinear, flat, imbricate to entangled.	Moderate to densely isidiate. Isidia cylindrical, simple or becoming branched, to 1 mm tall. Apices syncorticate	Black, sparsely to moderately rhizinate, rhizines simple, simple, black, to 0.4 mm long.	Medulla: divaricatic acid; ± stenosporic acid. Cortex: HNO3 + blue-green	Australia, New Zealand, South Africa
X. verruculifera	1–2 mm broad, subirregular to sublinear, contiguous to imbricate	Sparcely to densely isidiate. Isidia pustular, erumpent.	Dark brown to black, moderately rhizinate, rhizines concolorous, to 0.8 mm long	Medulla: divaricatic acid; ± stenosporic and gyrophoric acids. Cortex: HNO3 + blue-green	North Africa, Europe, North America