BGBM: lichen keys, CR Leiorreuma-Platythecium

The species of Leiorreuma in Costa Rica

1A Disc grey; ascospores transversely septate, 8/ascus - - - 2
1B Disc dark red; ascospores muriform, 1/ascus - - - Leiorreuma "pseudomontagnei"

2A Hypostictic acid present; lowland species - - - Leiorreuma hypomelaenum
2B No substance present; montane species - - - Leiorreuma exaltatum

Leiorreuma exaltatum (Mont. & v.d.Bosch) Staiger (Phaeographis exaltata (Mont. & v. d. Bosch) Müll. Arg.) - Ascocarps elongate and sometimes stellately branched, raised, 0.5-0.8 mm wide; margins forming a low thalloid rim around the widely exposed, grey, flat disc; hymenium ca. 110-120 mu; ascospores 8/ascus, transversely septate, ca. 25 x 10-12 mu, 6-8 celled, with thick outer walls. Specimens studied: Sipman 46585, 46590.


Costa Rica (Sipman 46590); picture length = 7 mm.	Costa Rica (Sipman 46585); picture length = 7 mm.

Leiorreuma hypomelaenum - as L. exaltatum, with hypostictic acid.


in prep.

Leiorreuma "pseudomontagnei" - Ascocarps elongate and sometimes stellately branched, raised, 06-1.0 mm wide; margins forming a low thalloid rim around the widely exposed, dark red, flat to slightly convex disc; hymenium 120-130 mu; ascospores 1/ascus, muriform, ca. 100 x 25-30 mu, 30 x 5 celled. Specimens studied: Sipman 51613a, 51687. NOTES: The red disc and phaeographoid hymenium remind of Thecaria montagnei, which differs by stronger carbonisation and persistently concave, narrower discs.


Costa Rica (Sipman 51687); picture length = 7 mm.	Costa Rica (Sipman 51613a), old ascocarp; picture length = 7 mm.

The species of Phaeographopsis in Costa Rica

Phaeographopsis neotropica Kalb - Ascocarps elongate and sometimes branched, immersed, 0.1-0.3 mm wide, of irregular width; margins forming a whitish rim around the exposed, darkgrey, flat disc; hymenium ca. 50 mu, clear; ascospores 8/ascus, transversely septate, ca. 12 x 5 mu, 4 celled, with cylindrical lumina. Specimens studied: Sipman 51128, 51174A.


Costa Rica (Sipman 51128); picture length = 7 mm.	Costa Rica (Sipman 51174A); picture length = 7 mm.

The species of Platygramme in Costa Rica

1A Ascocarp base carbonized, black - - - Platygramme reticulata
1B Ascocarp base not carbonized, pale - - - 2

2A Ascospores transversely septate - - - Platygramme praestans
2B Ascospores muriform - - - Platygramme caesiopruinosa

Platygramme caesiopruinosa (Fée) Fée (Phaeographina caesiopruinosa (Fée) Müll. Arg.) - Ascocarps elongate and branched, raised, 0.6-0.8 mm wide; margins forming a thick thalloid rim, carbonized inside, around the widely exposed, grey, flat disc; hymenium 180-250 mu, inspersed; ascospores (2-)4-8/ascus, muriform, ca. 50-90 x 15-18(-25) mu, 15-25 x 3-5 celled, cells in transverse rows. Specimens studied: Sipman 47991C, 52021.


Costa Rica (Sipman 53293); picture length = 7 mm.	Costa Rica (Sipman 47991C); picture length = 7 mm.

Costa Rica (Sipman 51185); picture length = 7 mm.	Costa Rica (Sipman 51824); picture length = 7 mm.

Platygramme praestans (Müll. Arg.) Staiger (Phaeographis praestans Müll. Arg.) - Ascocarps elongate and branched, raised, 0.5-1.0 mm wide; margins forming a thick thalloid rim, inside carbonized, around the widely exposed, grey, flat disc; hymenium 160-170 mu, inspersed; ascospores 8/ascus, transversely septate, ca. 45-75 x 10-15 mu, 9-18 celled. NOTE: after Staiger 2002).


in prep.

Platygramme reticulata (Fée) Fée - Ascocarps elongate and branched, raised, 0.6-0.8 mm wide; margins forming a thick thalloid, inside carbonized rim around the widely exposed, grey, flat disc; hymenium 130-200 mu, inspersed; ascospores 2-4(-8?)/ascus, muriform, ca. 60-75 x 17-19 mu, ca. 16 x 3 celled. Specimen studied: Sipman 52072.


Costa Rica (Sipman 52072); picture length = 7 mm.

The species of Platythecium in Costa Rica

1A Ascospores submuriform, with longitudinal septa - - - 2
1B Ascocarps transversely septate, without longitudinal septa - - - 3

2A Disc blackish grey; ascospores about twices as long as wide, 3-4 x 1-2 celled, 9-15 x 5-8 mu - - - Platythecium allosporellum
2B Disc brownish grey; ascospores subsphaerical, 2 x 2 celled, ca. 9 x 7 mu - - - Platythecium sphaerosporellum

3A Disc yellow-brown - - - Platythecium grammitis
3B Disc dark brown - - - Platythecium leiogramma

Platythecium allosporellum (Nyl.) Staiger (incl. P. "nigrum") - Ascocarps densely branched, stromatoid or not, immersed, ca. 0.2 mm wide; margins forming a low thalloid rim around the immersed, blackish grey disc; hymenium 60-80 mu, clear; ascospores 8/ascus, submuriform, I+ blue-violet, ca. 9-15 x 5-8 mu, 4 x 1-2 celled. studied: Sipman 51913. NOTE: Description partly after Staiger (2002).


Costa Rica (Sipman 51913); picture length = 7 mm.

Platythecium grammitis (Fée) Staiger (Graphis grammitis Fée) - Ascocarps elongate and branched, finally raised, 0.1-0.2 mm wide; margins forming a low thalloid rim around the exposed, yellowish, flat disc; hymenium 60-80 mu, clear; ascospores 8/ascus, transversely septate, ca. 9-14 x 4-6 mu, 3 celled. NOTE: no CR specimen seen.


in prep.

Platythecium leiogramma (Nyl.) Staiger - Ascocarps elongate and branched, finally raised, 0.1-0.2 mm wide; margins forming a low thalloid rim around the exposed, dark brown, flat disc; hymenium ca. 80 mu, clear; ascospores 8/ascus, transversely septate or submuriform, ca. 9-13 x 4-5 mu, 3 x 1-2 celled. NOTE: no CR specimen seen.


in prep.

Platythecium sphaerosporellum (Nyl.) Staiger - Ascocarps densely branched, more or les stromatoid, immersed, ca. 0.2 mm wide, at the tips narrower and fissurine; margins forming a low thalloid rim around the immersed, brownish grey disc; hymenium ca. 40 mu, clear; ascospores 8/ascus, submuriform, I+ blue-violet, ca. 9 x 7 mu, 2 x 2 celled. Specimen studied: Sipman 53265.


Costa Rica (Sipman 53265); picture length = 7 mm.	id., ascospores in Lugol solution.