Basiony:Pyxine glebosa Tuck. Syn. N. Amer. Lich. (Boston) 1: 79 (1882), published in footnote no. 1, not the main text.
Type: Ecuador. Galapagos [specific locality and habitat not recorded], Hassler Expedition 1872, Hill s.n. (FH-TUCK 197448–lectotype selected here!).
Protologue (text of footnote 1). “… And a still more marked reduction of this type is presented by a lichen from volcanic rocks of the Galapagos Islands (Dr. Hill in Hassler Exp.) in which while the apothecia offer no differences unless possibly rather smaller spores, the thallus has passed wholly into convex, glebous areoles, somewhat lobed only at the circumference (P. glebosa, Mihi, herb.) …”
Thallus saxicolous, crustose to subfoliose, placodioid, the centre of elongate, typically distinctly convex, convoluted, gnarled, contiguous to ±separate areoles, irregularly radiating towards the margin and extending into contiguous to ±separate, apically broadened, convex to ±flattened marginal lobes; surface faintly olivaceous grey to pale or deep beige, becoming more intensely brown on extended storage, rarely darkened along the lobe margins, ±shiny, with a smooth texture, mainly epruinose, but usually with a very faint, farinose pruina confined to the lobe margin and lining the edges of central areoles; central areoles usually abundantly fertile, very rarely with sparse soralia; soralia very rarely present, convex, erumpent, circular to irregular, occasionally ±confluent, developing from the thallus surface, soredia ivory white, typically paler than the thallus surface, granular compact, ecorticate with sparse, short protruding hyphae [(45–)61–91(–122) µm in diam.]; cortex phenocorticate, with a 7.5–10 µm thick epinecral layer, interspersed with fine crystals and a pale yellowish brown pigment (both dissolving in K), phenocortical layer prosoparenchymatous (ca. 10 µm wide), interspersed with minute crystals (dissolving in K) and a few dead algal cells; medulla of ±densely interwoven, white hyphae, typically with a dirty orange brown pigment near the substrate (unidentified secalonic acid derivatives), IKI-, filled with minute crystals that dissolve in K and sparse, large crystals insoluble in K, no needles formed in H2SO4 (calcium oxalate absent). Apothecia emergent, soon sessile, disc black, typically epruinose to very faintly pruinose, rarely with a bluish tinge caused by a strong white pruina; initially lecideine with a thin proper margin, soon becoming lecanorine, engulfed in and obscured by a thick, often ±discontinuous thalline margin which becomes irregularly crenate with age; thalline exciple with cortex, photobiont layer and medulla, filled with abundant minute crystals (same reactions as the thallus); proper exciple initially conspicuous, dark brown to strongly carbonized, with age becoming reduced, fading to brown or becoming hyaline, extending from a deep, fuscous to reddish brown hypothecium that extends from the base into a short, fuscous brown to reddish brown stipe; subhymenium not distinctly differentiated from hypothecium, not inspersed; hymenium hyaline, not inspersed; epihymenium olivaceous, interspersed with hyaline to brownish granules and a diffuse, dull greenish pigment (K+ faintly violet), paraphyses with brownish pigment cap; asci clavate, 8-spored, similar to the Bacidia-type (central, unstained part cylindrical, but stained flanks merging at the tip); ascospores 1-septate, olive grey then deep brown, smooth, ellipsoid to narrowly oblong, with age ±constricted at septum and often with ±pointed ends, with moderate median and indistinct to soon distinct apical thickenings, cell lumina initially ±angular, but with age becoming thin-walled (±Dirinaria-type), (12–)13.5–19.5(–28.5) × (5–)6–8(–10) mm (n = 45), spore wall smooth, not ornamented. Pycnidia immersed, flask-shaped with colourless wall, and deep fuscous to olivaceous ostiole; conidia simple, bacilliform (slightly tapered at one end) (3–)4–6(–6.5) × ca. 1–1.5 mm (n = 15).
Etymology: From Latin "glebous", meaning lumpy, cloddy, gnarled.
Ecology and distribution: Occurs in the Galapagos from the coastal to the transition zone, in sunny to semi-shaded, rarely ±shaded, mostly wind- and rain exposed habitats like the top of boulders or the front of cliffs.
Notes: Specimens of D. glebosa are fairly uniform in their overall appearance. Recently collected specimens are pale olivaceous grey to pale greenish beige, their surface is shiny though sometimes barely dulled by a very fine, inconspicuous pruina. With storage in the herbarium, the colour of the thalli increasingly darkens and the holotype specimen in FH has become pale brown.
The species is aptly named, because the convoluted central areoles typically appear, knotty, gnarled, lumpy. The systematic position of this species has caused considerable confusion. Tuckerman (1882) described it within Pyxine, which is not surprising as it superficially closely resembles that genus. Thalli of D. glebosa form distinct marginal lobes which appear similar to those of P. endoleuca (Müll. Arg.) Vain. or P. petricola Nyl., but these lobes as well as the central areoles of D. glebosa always adhere directly to the substrate. The thalli do not develop a lower cortex and lack rhizines characteristic for Pyxine and hapters characteristic of Dirinaria.
Imshaug examined and annotated the type material in FH. He must have observed this difference when he annotated the species as Buellia glebosa, comparing it with B. straminea Tuck., a species with much finer lobed, placodioid thalli that are distinctly yellow due to the presence of xanthones.
According to his annotation, Weber studied the type specimen at FH in 1964, and added a lengthy note, writing: "Contrary to Imshaug’s annotation and his notes in Bryologist 58: 283. 1955 [Imshaug 1955], the type specimen is a Pyxine and not a Buellia...". Awasthi subsequently examined the FH material and apparently followed Weber, annotating the specimen as "Pyxine glebosa (Tuck.) Epithet. K+ purple".
Subsequently, Weber (1986) published his observations, but his statements in that publication are contradictory. For P. glebosa, Weber (1986, p. 462) states: "Nothing like it has been collected recently." This was incorrect as he collected specimens of Diploicia glebosa (e.g., COLO 294551; L-62971, COLO 294659; L-62862, cited below), but identified them as Dirinaria caesiopicta (Nyl.) D.D. Awasthi. Among the COLO collections identified as D. caesiopicta several do not belong to Dirinaria; they lack a lower cortex and hapters. Most of these specimens with a lower medulla directly adhering to their substrate are here identified as the newly described Diploicia neotropica, but a few belong to D. glebosa.
It is no surprise that these two Diploicia species have been confused with Pyxineendoleuca and Dirinariacaesiopicta. Whereas the typical, shiny, smooth, beige forms of D. glebosa more closely resemble a Pyxine, the strongly pruinose forms of D. neotropica are superficially similar to those of Dirinaria caesiopicta.