Sticta rhizinata Moncada & Lücking, 2012

Moncada, Bibiana & Lücking, Robert, 2012, Ten new species of Sticta and counting: Colombia as a hot spot for unrecognized diversification in a conspicuous macrolichen genus, Phytotaxa 74 (1), pp. 1-29 : 17-18

Sticta rhizinata Moncada & Lücking , spec. nov. ( Fig. 7 )

MycoBank #801849

Differing from Sticta weigelii in the bryophilous growth habit and the long rhizines on the underside.

Holotype: — COLOMBIA. Cundinamarca. Mun. La Calera, Parque Nacional Natural Chingaza, Monterrendondo ; 4º 44' N, 73º 50' E; 3430 m; 13 Apr 2011, Moncada 4638 ( UDBC; isotypes: COL, F).

Primary photobiont cyanobacterial ( Nostoc ). Stipe absent. Thallus irregular to suborbicular, up to 15 cm diam., moderately branched, with 3–5 branches per 5 cm radius, branching anisotomous to pleurotomous; lobes laciniate, horizontal, adjacent to imbricate, involute, their apices rounded, involute, their margins crenate to sinuous, not thickened; lobe internodes (6–)8–13(–16) mm long, (6–)12–28(–32) mm broad; thallus coriaceous. Upper surface smooth to weakly foveolate or rugose–costillate, green-brown when fresh, redbrown and darkening towards the apices in the herbarium, shiny; surface glabrous, without papillae and pruina, but with irregular, yellowish maculae; marginal cilia absent. Apothecia not observed. Isidia abundant, predominantly marginal, aggregate, branched to coralloid, with rather long branches, vertically to obliquely oriented, up to 0.5 mm long and 0.5 mm broad, darker than the thallus, blackish brown to black, shiny, cylindrical to slightly flattened and becoming spathulate; basal stalk when present cylindrical, without cyphellae. Lower surface uneven, brown; primary tomentum dense up to the margin, thick but thinner towards the margin, spongy, rough, brown-black; secondary tomentum arachnoid, pale. Rhizines abundant, submarginal, aggregate, fibrillate and covered with secondary tomentum, brown-black, up to 10 mm long. Cyphellae 1–20 per cm 2 towards the thallus center and 61–100 per cm 2 towards the margin, scattered, round, urceolate with wide pore, erumpent to prominent, remaining below the level of the primary tomentum, with the margin elevated and involute, pale brown, without tomentum; pore (0.25–)0.4–0.8(–1.5) mm diam.; basal membrane pubescent, white, K + yellow, C –, KC–, P –. Medulla compact, cream-colored, K + yellow, C –, KC–, P –. No substances detected by TLC.

Upper cortex paraplectenchymatous, 45–65 µm thick, formed by two different layers: upper layer consisting of 1–2 cell layers with cells 3–4 µm diam., their walls 1.2–2.5 µm thick and their lumina rounded to isodiametric, 1.2–2.5 µm diam.; lower layer consisting of 2–3 cell layers; cells 6–11 µm diam., their walls 1–1.2 µm thick and their lumina rounded to isodiametric, 5–10 µm diam. Photobiont layer 25–50 µm thick, its cells 10–20 µm diam. Medulla 55–175 µm thick, its hyphae 2.5 µm broad, without crystals. Lower cortex paraplectenchymatous, 25–40 µm thick, with 3–4 cell layers; cells 6–16 µm diam., their walls 1–1.5 µm thick. Hairs of lower primary tomentum 110–470 µm long, in fascicles of 12–20, branched hyphae, septate with their apices intertwined. Hairs of lower secondary tomentum 8–18 µm long, of single, branched, moniliform hyphae with free apices. Cyphellae cavity 30–150 µm deep; cells of basal membrane without papillae.

Distribution and Ecology: —South American Andes ( Colombia). Sticta rhizinata has been found between 2300 and 3720 m altitude in subandine forest and páramo regions in microhabitats with low to high light intensity. It occurs on the western slopes of the Cordilleras Central and Occidental. Typically it grows on the ground inbetween bryophytes of the genera Plagiochila , Frullania Raddi (1818) , Metzgeria , Campylopus Brid. ( Bridel 1819) and Dicranum Hedw. ( Hedwig 1801) , and lichens of the genera Hypotrachyna (Vain.) Hale ( Hale 1974) , Everniastrum Hale ex Sipman ( Sipman 1986) , and Peltigera Willd. ( Willdenow 1787) .

Etymology: —The epithet refers to the very conspicuous rhizines of this species, quite different from other similar species in the Sticta weigelii complex.

Remarks: —This species belongs in the Sticta weigelii complex, being characterized by a cyanobacterial photobiont and comparatively narrow, much branched lobes with marginal isidia ( McDonald et al. 2003; Galloway 2006). Within that complex, S. rhizinata is well-characterized by its very narrow, laciniate lobes forming large and conspicuous rhizines on the underside, as well as its ecology, being typically found growing between bryophytes on the ground.

Additional specimens examined (paratypes): — COLOMBIA. Boyacá: Mun. Aquitania, Páramo de los Pozos ; 3115–3320 m; 26 Feb 2004, Medina & Castillo 10 ( UPTC) . Mun. Duitama, road from Duitama to Charalá ; 3070 m; 23 Jul 1985, Escobar & Santa 213 ( HUA) . Mun. El Cocuy, Parque Nacional Natural El Cocuy, Alto de la Cueva ; 3800 m; 21 Apr 2011, Fonseca & Martínez 224 ( UDBC) . Mun. Gachantivá, Vereda la Ciénaga, vía Cáscada La Honda ; 2300 m; 18 May 2001, Moncada & Dávila 1846b ( UDBC) . Mun. Socha, Páramo de Pisba, road from Socha to La Punta, km 61.5, Alto de Granados ; 3600 m; 10 Jun 1972, Cleef 4356 ( B, COL, L) . Cundinamarca. Alto de la Viga, Páramo de Cruz Verde, Camino Real towards Las Lagunas ; 3450 m; 28 Nov 1974, Van den Hammen 3113 ( B, COL) . Parque Nacional Natural Sumapaz, Páramo de Chisacá, Santa Rosa , Bodegas de Sumapaz , Valle del Rio Colorados ( Santa Rosita ); 3470 m; 20 Aug 1976, Van den Hammen & Jaramillo-M. 4420 ( B, COL) . Parque Nacional Natural Sumapaz, Corregimiento Nazareth, summit to the east of Caseta Los Pinos ; 3450 m; 11 May 2004, Moncada & Dávila 2178 ( UDBC) . Surroundings of Laguna de Chisacá ; 4º 17' N, 74º 12 E; 3724 m; 15 Aug 2010, Moncada et al. 4063 ( UDBC) . Mun. Chipaque, Vereda Marilandia, vía Santuario ; 2400 m; 8 Sep 2011, Moncada 4790, 4796, 4896 ( UDBC) . Mun. Choachí, El Verjón; PE Matarredonda ; 04º 34' N, 74º 00' E; 2900–3220 m; 8 May 2010, Moncada 3163 ( UDBC) ; ibid.; 3220 m; 23 Jan 2011, Moncada 4535 ( UDBC) . Mun. Guasca, Páramo de Guasca ; 3350 m; 18 Aug 2011, Moncada 4766 ( UDBC) . Mun. La Calera, Parque Nacional Natural Chingaza, Monterrendondo ; 4º 44' N, 73º 50' E; 3430 m; 13 Apr 2011, Moncada 4635b ( UDBC) . Mun. Supatá, Alto El Tablazo, Carretera Estación Radar to Supatá ; 3400 m; 11–12 Sep 1984, Aguirre & Sipman 5262 ( B, COL) . Risaralda: Mun. Santa Rosa de Cabal, Vereda El Cedral , vía El Cedral to Laguna del Otún , 100 m of Finca Ceilán ; 2300 m; 3 Sep 2003, Moncada & Dávila 2060 ( UDBC) .

Figures

FIGURE 7. Sticta rhizinata (holotype collection). A. Thallus in situ. B. Lower surface of thallus in situ showing rhizines. C. Thallus in herbarium. D. Lower surface enlarged showing rhizines. E. Marginal isidia. F–G. Detail of marginal isidia. H. Microscopic section through thallus showing lower cortex and moniliform tomentum. Scale in A–D = 5 mm, in E–G = 0.5 mm, in H = 20 µm.