Table 4.

Diagnostic characters in species with long, parallela-like ascomata

	X. carneopallida	X. difformis	X. pallens	X. parallela	X. rubescens	X. septentrionalis	X. stenospora
Ascomatal regeneration	bidirectional, linear	irregular, deformed	bidirectional, multiple growth tips, old ascomata forming stars	mainly unidirectional, often one apothecium end blunt	bidirectional, multiple growth tips, old ascomata forming (irregular) stars	bidirectional, multiple growth tips, old ascomata occasionally forming weak stars	bidirectional, linear, old ascomata tending to become deformed
Ascoma length/width ratio (mean±SD)	2.75–17.5	4.12±2.09	7.79±4.75	5.69±2.56	8.73±7.45	6.89±3.78	3.71±1.33
Ascomatal margin colour and habit	pale, lighter than disc, straight	brown to pale cream, thin, flexuose	brown to cream, ±straight	brown	brown to cream, flexuose	brown to cream, ±straight	brown to black, usually “crimped” or flexuose
Birefringence in exciple (POL+)	entire exciple full of true crystals	entire exciple full of true crystals	inner exciple	inner exciple	entire exciple full of true crystals	entire exciple full of true crystals	inner exciple
Ascoma “peeling”	no	no	frequently	frequently	frequently, also fragmenting	no	no
Hymenial pigments	±unpigmented	brown and sometimes also gray	brown	brown and gray	brown and gray	brown and sometimes also gray	gray and brown
Hymenial amyloidity	euamyloid	euamyloid	hemiamyloid	hemiamyloid	hemiamyloid	hemiamyloid	hemiamyloid
Paraphysis terminal cells	not expanded	expanded to 6 μm	expanded to 6 μm	expanded to 6 μm	expanded to 5 μm	expanded to 6.5 μm	expanded to 5 μm
Mean ascospore length (μm)	11.4	12.4–14.5	12.3–16.1	11.3–14.5	10.8–12.5	11.9–16.1	10.9–12.7
Mean ascospore width (μm)	5.3	4.1–6.1	5.8–7.2	5.9–7.6	5.5–6.7	5.9–7.8	3.3–4.5
Ascospore L/W ratio (mean±SD)	1.9–2.4	2.74±0.74	2.1 ±0.4	2.03 ±0.35	1.98 ±0.33	2.05±0.41	3.06±0.33
Thallus	well developed, white, lumpy	endoxylic to well developed, white, lumpy	well developed, white, forming lens-like surficial patches	consisting of lichenized algal clumps between wood fibres, seldom surficial	granular to rimose and lumpy	consisting of lichenized algal plugs between wood fibres, breaking out in goniocysts	consisting of sparse lichenized algal plugs between wood fibres
Gonio cysts	absent	absent	often present	often present	usually present	constant, abundant, forming soralia	absent
Major substances	norstictic and stictic acids in ±equal amounts	norstictic only or norstictic and stictic acids in ±equal amounts	stictic acid (major), norstictic (trace)	stictic acid or substances not detected	norstictic only or norstictic and stictic acids in ±equal amounts, norstictic localized	norstictic only or norstictic and stictic acids in ±equal amounts	stictic acid or substances not detected
Distribution	Boreal-montane, North America, Europe, Asia	Boreal-montane, western North America, Europe	Boreal-montane, North America, Europe, Asia	Boreal-montane, North America, Europe, Asia	Boreal-montane, western North America, Europe, central Asia	Boreal-montane, North America	Inland western North America