Cladonia macilenta Hoffm. (1796: 126)

Yánez-Ayabaca, A., Ahti, T. & Bungartz, F., 2013, The Family Cladoniaceae (Lecanorales) in the Galapagos Islands, Phytotaxa 129 (1), pp. 1-33 : 19-20

Cladonia macilenta Hoffm. (1796: 126)

( Fig. 5a )

Primary thallus subpersistent, of crenulate squamules, esorediate or sometimes with soredia, epruinose; podetia common, greenish gray or pale yellow, occasionally becoming brown (melanotic), but not necrotic, short to elongate; 0.8–2.5 cm tall, simple to slightly branched, tips obtuse or acute; ascyphose; surface mostly ecorticate, with cortex restricted to the base of the podetium and immediately below the apothecia; densely covered with farinose soredia, scarce microsquamules, lacking granules; pycnidia with bright red jelly, apothecia closely aggregated, with bright red jelly.

Spot tests and chemistry: Medulla P+ yellow K+ yellow, C−, KC−, UV−; thamnolic and didymic acid (chemotype I).

Distribution and ecology: Currently known only from Isabela, Pinta, Pinzón, San Cristóbal, Santa Cruz, and Santiago Island; a relatively rare species, known from the humid zone only, on soil or rotten wood, less commonly on bark.

Notes: The species differs from C. didyma by consistently producing abundant soredia, but scarcely any microsquamules. Cladonia didyma instead has densely microsquamulose podetia, and although its squamules can be minute, almost granular, this species only very rarely forms true soredia.

Cladonia bungartzii is similar to both species. Like C. macilenta it is densely sorediate, but has podetia that are mostly corticate. This cortex, although not restricted to the base but present along the length of the podetium, does not remain intact where soredia develop. The stereomes of C. bungartzii are generally not as compact as those of C. macilenta and C. didyma , instead they are composed of relatively loosely interwoven hyphae and unlike the other two re-fruited species, podetia of C. bungartzii are therefore characterized by distinct longitudinal cracks of the cortex and stereome.

All Galapagos specimens contain thamnolic and didymic acid and specimens previously identified as C. macilenta var. bacillaris do not correspond to this taxon.

Selected specimens examined: ECUADOR. GALAPAGOS: Isabela Island, Volcán Alcedo, outer SEexposed slope and crater rim, 0°27’29”S, 91°7’19”W, 1089 m, humid zone, on wood, 5 Mar 2006, Aptroot, A. 65100 ( CDS 31682) , upper NNW-exposed slope inside the crater, 0°27’27”S, 91°7’23”W, 1055 m, humid zone, on bark, 3 May 2006, Bungartz, F. 4093 ( CDS 28057) ; Volcán Darwin, southwestern slope, above Tagus Cove , 0°13’43.29”S, 91°19’47.3”W, 724 m, transition zone, on soil, 11 Dec 2007, Bungartz, F. 7470 ( CDS 37957) ; Volcán Sierra Negra, close to the southern crater rim, along the trail to Alemania , 0°51’12.69”S, 91°8’40.5”W, 1055 m, humid zone, on plant debris, 16 Aug 2008, Bungartz, F. 8342 ( CDS 40988) , close to Volcán Chico , along the trail, 0°46’57.79”S, 91°5’59.4”W, 944 m, transition zone, on rock, 14 Aug 2008, Truong, C. 1280 ( CDS 39591) . Pinta Island, on top of the highest point of the island, 0°35’3”N, 90°45’12”W, 625 m, humid zone, on soil, 26 Feb 2007, Bungartz, F. 5743 ( CDS 33395) . Pinzón Island, E-facing side of a valley on the W-slope of the highest mountain, 0°36’49”S, 90°40’14”W, 294 m, transition zone, on soil, 16 Feb 2006, Bungartz, F. 3606 ( CDS 27424) . San Cristóbal Island, in encanada near El Junco, humid zone, on bark, 21 May 1976, Lanier, J. ( COLO 298441 ) . Santa Cruz Island, vicinity of Academy Bay, La Copa (= Media Luna ), humid zone, 15 Feb 1964, Weber, W.A. 426 ( COLO 193442 ) , along trail from Media Luna to El Puntudo, 0°39’9.80”S, 90°18’59.3”W, 674 m, humid zone, on bryophytes and bark, 8 Oct 2008, Bungartz, F. 8142 ( CDS 40788) . Santiago Island, along the trail from Bucanero to Jaboncillos, ca. 1 km below the summit, Cerro Gavilán , 0°11’45”S, 90°47’20”W, 680 m, transition zone, on wood, 22 Mar 2006, Aptroot, A. 65433 ( CDS 32019) .

Cladonia nana Vain. (1894: 23)

( Fig. 5b )

Primary thallus persistent, thin, coralloid, of elongate to laciniate squamules, corticate above and cottony ecorticate below, the lower side covered with coarsely granular-soredia; epruinose, podetia typically very few or absent, if present, short, 0.5–1.5 (–2) cm tall; phyllopodiate; simple to slightly branched; terete to flattened; tips blunt; surface initially corticate, but soon granular-areolate, peeling off as abundant microsquamules, lacking soredia; pycnidia with hyaline jelly, apothecia with brown jelly.

Spot tests and chemistry: P+ red; K− or + light brown, C−, KC−, UV−; fumarprotocetraric and traces of protocetraric acid.

Distribution and ecology: Known from Floreana, Isabela, Pinta, Santa Cruz, and Santiago Island; possibly the most common species dominated by squamules, often forming extensive matts, most common in the humid and upper transition zone, few collections from the dry zone; on a wide variety of substrates, soil, rotten wood, or as epiphyte.

Notes: The dominant coralloid primary thallus of abundant elongated to strap-shaped squamules with small or even no podetia cannot be confused with any other Galapagos species.

Selected specimens examined: ECUADOR. GALAPAGOS: Isabela Island, Volcán Alcedo, on the crater rim near the hut, 0°26’33”S, 91°5’31”W, 1100 m, humid zone, on bark, 7 Mar 2006, Aptroot, A. 65201 ( CDS 31787) , on soil, 7 Mar 2006, Aptroot, A. 65239 ( CDS 31825) ; Volcán Cerro Azul, S-slope above Iguana Cove , 800 m, humid zone, on steep rocky bank, 24 June 1976, Sipman, H.J.M. L-84 ( COLO 297876 ) . Volcán Sierra Negra, top of eastern crater rim, 0°48’22.30”S, 91°5’15.8”W, 991 m, humid zone, on wood, 8 Sept 2007, Bungartz, F. 6801 ( CDS 36220) . Pinta Island, along the trail up to the summit from the S-coast, 0°34’47”N, 90°45’8”W, 493 m, humid zone, on bark, 26 Feb 2007, Bungartz, F. 5778 ( CDS 33451) . Pinzón Island, in the valley on the W-slope of the highest mountain, 0°36’41”S, 90°40’11”W, 310 m, dry zone, on detritus, 16 Feb 2006, Aptroot, A. 64102 A ( CDS 30663) . Santa Cruz Island, vincinity of Academy Bay , La Copa (= Media Luna), 1964 Weber, W.A. 425 (L-40633; H; COLO 192156 ) , Bellavista, near parking place for trail to Media Luna , 0°40’10”S, 90°19’22”W, 400 m, humid zone, on wood, 27 May 2005, Aptroot, A. 63134 ( CDS 29864) , 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°21’59.1”W, 617 m, transition zone, on soil, 21 Oct 2007, Bungartz, F. 7137 ( CDS 37622) . Santiago Island, along the trail from the caseta in La Central to La Bomba (at the coast), cerro ca. 1 km NE of the caseta and on the W-side of the trail, 0°14’10”S, 90°44’41”W, 664 m, transition zone, on rock, 25 Mar 2006, Bungartz, F. 4855 ( CDS 29051) , summit of Cerro Gavilán , inner N- and NE-exposed crater rim, 0°12’20”S, 90°47’3”W, 840 m, humid zone, on rock, 23 Mar 2006, Aptroot, A. 65700 ( CDS 32292) , Aptroot , A. 65711 ( CDS 32303) , area around the entrance of the lava tunnel at La Central , 0°14’23”S, 90°45’8”W, 667 m, humid zone, on rock, 24 Mar 2006, Bungartz, F. 4850 ( CDS 29026) .

Figures

FIGURE 5. a the predominantly sorediate podetia of Cladonia macilenta (Bungartz 7758, scale 3 mm); b highly dissected, minute squamules with very short podetia, characteristic of Cladonia nana (Aptroot 64501, scale 5 mm); c–d Cladonia polyscypha. c general growth aspect (Bungartz 3970, scale 5 mm); d close-up with podetia terminating in narrow scyphi (Aptroot 64514, scale 5 mm); e podetia of Cladonia pulverulenta (Aptroot 64518, scale 5 mm); f broad, trumpet-shaped podetia with coarse corticate granules