Holotype: East Asia, Malasia: Malacca, Tanjong, on coccoa-palms, 09-Nov-1866, Maingay 2865 (H-Nyl!, isotype in BM!).
Thallus corticolous, greenish gray becoming pale dusky, green or gray in the herbarium, medulla white. Lobes ca. 0.3–1.2 mm wide, , sublinear to distinctly laciniate, dichotomously, trichotomously or irregularly branched, contiguous to ± slightly imbricate, adnate, firmly attached; apices truncate to subtruncate; margin smooth and sinuous to subcrenate or subirregular. Upper surface continuous, rarely with irregular fissures, smooth, without laminal ciliary bulbs, maculae weak to distinct, punctiform, laminal, ±frequent, amidst scars from isidia that have broken off; adventive lacinules absent to frequent, short, randomly distributed along the margins or rarely laminal amidst the isidia. Cilia black to deep brown, simple to eventually furcate and then dichotomously or irregularly branched, abundant, but confined to the lobe margins, with basal bulbs. Soredia and pustules absent. Isidia frequent, laminal to rarely marginal, simple to sparsely branched, eciliate. Lower surface ±shiny, smooth to subrugose, black to very deep brown and densely rhizinate throughout (Fig. 2D) or gradually becoming paler and often less rhizinate towards the margin (Fig. 2E), and moderately to densely rhizinate in the center. Rhizines black to brown or pale brown, simple soon becoming furcate and then dichotomously or irregularly branched, abundant and evenly distributed (almost like a tomentum), some rhizines with inconspicuous basal bulbs. Apothecia rare (not observed in Galapagos specimens), if present laminal or submarginal, ±plane, adnate; margin smooth, ecoronate; disc dark brown, epruinose, imperforate; ascospores ellipsoid to oval, 5.0–8.0 (–9.0) × 4.0–5.0 µm, epispore ca. 1.0 µm thick (Benatti & Elix 2012). Pycnidia (not examined in Galapagos specimens) laminal to submarginal, with black ostioles; conidia bacilliform to bifusiform, (4.0–) 5.0–6.0 × ca. 0.5−1.0 µm (Benatti & Elix 2012).
Spot test reactions. Cortex K+ yellow, C−, KC−, P+ yellow, UV− (dull); medulla K−, C+ pale pink, KC+ pale pink, P−, UV± bluish (reaction often faint and inconspicuous).
Chemistry. Cortex with atranorin, medulla with gyrophoric, ±lobaric, and oxolobaric acids, ± traces of hiascic acid (reports of lecanoric acid in addition to gyrophoric acid are doubtful).
Distribution and ecology. Cosmopolitan, Asia (Philipines, Malaysia). South America (French Guiana, Brazil) (see Benatti & Elix 2012); new to Galapagos and Ecuador; about half of the previous specimens reports of B. laevigatula from Galapagos (Floreana, San Cristóbal, Santa Cruz, Santiago, Volcán Cerro Azul and Volcán Sierra Negra, on Isabela) belong to this species, most specimens have been found from the dry to the transition zone, but like B. scortella it also occurs in the humid zone, the ecological amplitude of B. subdissecta may be wider than that of other species of Galapagos Bulbothrix. It is the only species that was found both in sunny, exposed and sheltered, shaded habitats, where it occurs on the trunks or stems, branches and twigs of native trees, rarely shrubs, most frequently on bark of Bursera graveolens and Psidium galapageium, but also on Zanthoxylum fagara, Cordia lutea, and Hippomane mancinella.
Specimens examined. Ecuador. Galapagos Islands: Isla Floreana, trail from La Primavera Farm to La Corona and Arco de la Reina, southeastern part of the island, permanent plot 32, 1˚ 18’ 56.79” S, 90˚ 25’ 13.80” W, 278 m alt., dense forest of low Psidium guajava forest with some Zanthoxylum fagara trees, some Macraea laricifolia, Clerodendrum molle, Tournefortia rufo-sericea and Chiococca alba in lower humid zone; bryophytes hanging in curtains from trunks and branches especial, on fallen twig, 24-Jan-2011, Yánez, A. 2084 (CDS 48430). Isla San Cristóbal, Cerro Partido along trail from entrance to Cerro Pelado to El Ripioso, 0˚ 51’ 23.00” S, 89˚ 27’ 37.00” W, 376 m alt., rocky SW-exposed slope of hill with Jasminocereus thouarsii, Clerodendrum molle var. glabrescens, Psidium galapageium, Bromeliaceae and ferns growing in rock crevices, on twigs and branches of Croton scouleri; semi-shaded, wind- and rain-sheltered, 28-Apr-2007, Bungartz, F. 6620 (CDS 34840). Isla Santa Cruz, above the quarry Mina Granillo Rojo, off the main road to the channel, on the N-side of the island, 0˚ 37’ 5.79” S, 90˚ 21’ 59.10” W, 617 m alt., open and dry forest of mainly Psidium galapageium, with some Scalesia pedunculata and Pisonia floribunda, and basalt outcrops, on SE-exposed trunk of Bursera graveolens (ca. 10 cm in diam.); semi-shaded, wind- and rain-exposed, 21-Oct-2007, Bungartz, F. 7119 (CDS 37604); along the road from Bellavista to El Garrapatero, at the boundary of the National Park, 0˚ 40’ 14.00” S, 90˚ 15’ 58.00” W, 252 m alt., with Zanthoxylum fagara, Lantana camara, Citrus sp. and Croton scouleri, 14-Feb-2006, Aptroot, A. 63933 (CDS 30489); Camote, finca de René Valle, lindero del Parque Nacional Galápagos, al borde, 0˚ 38’ 15.19” S, 90˚ 17’ 53.29” W, 471 m alt., bosque secundario de Psidium galapageium y Scalesia pedunculata, perturbado, restaurado y PNG intervenido por especies vegetales invasoras, on Psidium galapageium altura al pecho, exposición NE, 21-Sep-2007, Nugra, F. 449 (CDS 36763); on farm N of Bellavista, 0˚ 41’ 4” S, 90˚ 19’ 29” W, 250 m alt., agricultural area, on Prosopis, 30-May-2005, Aptroot, A. 63315 (CDS 30055). Isla Santiago, permanent plot # 5 Guayabillos nuevo abierto, 0˚ 14’ 0” S, 90˚ 43’ 52” W, 625 m alt., open woodland of Psidium galapageium, Zanthoxylum fagara, Bursera graveolens, Trema micrantha and shrubs of Clerodendrum molle in between, on Trema micrantha, 25-Mar-2006, Aptroot, A. 65592 (CDS 32181). Isla Isabela, Volcán Cerro Azul, path from the fist Caseta del Parque to Caleta Iguana, appox. a third of the way, 0˚ 59’ 9.50” S, 91˚ 26’ 4.90” W, 224 m alt., dense Guayaba (Psidium guajava) woodland with few large Zanthoxylon fagara, pega pega (Pisonia floribunda) and Scalesia cordata trees, understory with Tournefortia rufo-sericea shrubs and ferns, on Manzanilla, cicatriz, 08-May-2012, Nugra, F. 1102 (CDS 52454); path from the fist Caseta del Parque to Caleta Iguana, approx. a third of the way, 0˚ 59’ 9.50” S, 91˚ 26’ 4.90” W, 224 m alt., dense Guayaba (Psidium guajava) woodland with few large Zanthoxylon fagara, pega pega (Pisonia floribunda) and Scalesia cordata trees, understory with Tournefortia rufo-sericea shrubs and ferns, on tree inside small bosque, shaded, epyphytic, trunk, 07-May-2012, Spielmann, A. 10642 (CDS 52009); steep outer slopes of the volcano above Cerro Verde, 0˚ 57’ 28.50” S, 91˚ 24’ 29.10” W, 1238 m alt., grassy pasture with scarce Tournefortia rufo-sericea scrub, very few Zanthoxylon fagara and Guayabillo (Psidium galapageium) trees, on small agglomeratoin of shrubs,Guayabillo, semi-shaded, branches and twigs, epiphyte, 07-May-2012, Spielmann, A. 10610 (CDS 51977); Volcán Sierra Negra, Isabela Island, La Cueva Sucre, abandoned farm bought by the National Park, 0˚ 50’ 34.60” S, 91˚ 1’ 39.10” W, 362 m alt., agricultural area, Syzygium jambos trees and Coffea arabica shrubs along a trail, on leaves of Syzygium jambos; shaded, wind- and rain-sheltered, 15-Aug-2008, Bungartz, F. 8273 (CDS 40919).
from: Bungartz, F., Benatti, M.N. & Spielmann, A. (2013) Parmeliaceae of the Galapagos Islands, part I: The genus Bulbothrix Hale. The Bryologist116(4): 358–372.