Steinera Zahlbr.

Ertz, Damien, Poulsen, Roar S., Charrier, Maryvonne & Søchting, Ulrik, 2017, Taxonomy and phylogeny of the genus Steinera (Arctomiales, Arctomiaceae) in the subantarctic islands of Crozet and Kerguelen, Phytotaxa 324 (3), pp. 201-238 : 209-210

Steinera Zahlbr.

Deutsche Südpolar-Expedition 1901-1903, 8 Bot.: 41 (1906). Type: Steinera molybdoplaca (Nyl. ex Cromb.) Zahlbr.

Description (adapted from Henssen & James 1982): Thallus subfoliose to placodioid (sometimes entirely isidiate and then appearing composed of ascending, terete lobes), loosely to closely attached to the substrate, rosette-shaped, to 6 cm diam., margin distinctly and ±regularly lobate; marginal lobes separated by deep fissures, rarely partly overlapping, radiating. Upper surface smooth to roughened, sometimes scabrid. Lower surface smooth, usually without rhizohyphae. Prothallus not developed. Apothecia discrete or contiguous, usually laminal and mostly restricted to the central areas of the thallus, developed on the upper surface of the thallus, up to 1 mm diam., immersed or eventually sessile and then often with a thin thalline margin concolourous with the thallus. Thalline anatomy: hyphae in upper 1/2–1/3 of thallus running perpendicularly to surface; upper ±algal-free layer (or ‘cortex’) consists of a layer of thin-walled, oval, cuboidal or shortly elongated cells, usually ±paraplectenchymatous and overlaid by an uneven, amorphous, semi-translucent, thin, necrotic layer. Photobiont a species of Nostoc , mainly aggregated in the upper c. 1/3–1/2 of the thallus; individual photobiont cells pale orange to olivaceous green (heterocytes paler, yellowish), spherical or slightly wider than long, in clusters surrounded by a gelatinous sheath; clusters typically arranged in vertically elongated fascicles between the fan-shaped ascending hyphae, being usually pale orange near the surface and greenish in deeper parts of the thallus; hyphae below algal layer usually more loosely arranged, ±horizontally radiating towards the apices of the marginal lobes, generally interspersed with simple chains of algal cells. Lower surface with a ±irregularly developed and usually ±paraplectenchymatous cortex layer in the distal parts of thallus. Apothecial anatomy: Excipulum inconspicuous or thin, consisting laterally of short-celled, hyaline hyphae arranged in parallel, basally becoming ±paraplectenchymatous; sometimes with a thin thalline margin at the outer edge containing clusters of the photobiont. Hymenium hyaline, not inspersed, I+ deep dark blue turning dark reddish brown, KI+ deep blue; epihymenium pale yellowish to pale brown, rarely hyaline, I+ deep dark blue turning dark reddish brown, K– or K+ faintly darker brown; paraphyses simple to branched-anastomosing mainly in upper parts of hymenium; apical cells shortened, swollen. Hypothecium hyaline, consisting of densely short-celled hyphae above, becoming ±paraplectenchymatous below, KI+ blue. Asci (4–)8- spored, clavate, usually with a distinct foot, with a well-developed tholus; ascospores transversely septate, straight or slightly curved, narrowly ellipsoid, oblong or fusiform, with rounded or ±acicular ends, without a distinct gelatinous sheath, I–, KI–. Pycnidia rarely present, immersed in thallus; conidiophores short-celled; conidia hyaline, rod-shaped to ellipsoid.

Chemistry: No lichen substances detected by TLC.

Notes: Zahlbruckner (1906) typified the new genus Steinera on ‘ Amphidium molybdoplacum ’ as he wrote (pg 42): “Die neue Gattung wird auf jene Flechte begründet, welche Nylander under dem Namen ‘ Amphidium molybdoplacum ’ beschrieb”. S. glaucella and S. molybdoplaca were not recognized as separate species by Zahlbruckner (1906) who treated S. glaucella as a synonym of S. molybdoplaca in his publication describing the genus Steinera . Unfortunately, S. glaucella was published one month earlier than S. molybdoplaca , a fact to which Tuckerman (1877) drew attention. As a consequence, Dodge (1948) published the new combination Steinera glaucella (Tuck.) Dodge and treated Steinera molybdoplaca as a synonym, with “ Amphidium molybdoplaca Nyl. ” cited as being the type of the genus Steinera .

We compared the types of S. glaucella and S. molybdoplaca and despite the fragmentary nature of the type of S. glaucella it became clear that they represent two different species. They share the greyish thallus colour but differ in a number of other important characters, such as thallus size, and apothecium and spore characters, and belong to the two different species groups that we have recognized in Steinera sensu Henssen & James (1982) , with S. glaucella belonging to the group with simple spores and S. molybdoplaca to the group with septate spores. Therefore, Dodge (1948) wrongly treated Steinera glaucella as a species having the morphology of Steinera molybdoplaca sensu Nylander (original description of the species), and thus as a species having mainly 3-septate ascospores and a large thallus that might reach 4 cm in diameter. Later, Henssen & James (1982), who also considered S. molybdoplaca as a synonym of S. glaucella , used “ Steinera glaucella ” as the type species of the genus Steinera . Because Zahlbruckner (1906) wrongly treated Pannaria glaucella (published in October 1875) as a synonym of Amphidium molybdoplaca (published in November 1875) in the original description of the genus Steinera, Henssen & James (1982, p. 246) wrote that “Even if Steinera glaucella and S. molybdoplaca had been found to be different entities the specific epithet molybdoplaca was rendered nomenclaturally superfluous when published (Art. 63). This is because the earlier name Pannaria glaucella , which should have formed the basionym, is cited in the synonymy of Zahbruckner’s new combination Steinera molybdoplaca , which was based on Amphidium molybdophaeum , which was published a month later.” [Note: Art. 63 at this time is Art. 52 in the current code of nomenclature]. However, Zahlbruckner (1906) clearly typified the genus Steinera on “ Amphidium molybdoplacum ” (see above), thus on a legitimate basionym having its own type specimen different from that of Steinera glaucella . He also correctly illustrated the 3-septate ascospores for S. molybdoplaca showing that his concept of S. molybdoplaca was that of the type specimen of that species and not that of S. glaucella . It must be noted that the new combination Steinera molybdoplaca (Nyl. ex Cromb.) Zahlbr. is not illegitimate (Art. 52.3, see also example 15 about Chloris radiata and Andropogon fasciculatus ). Zahlbruckner (1906) wrongly considered “ Pannaria glaucella Tuck. ” as a synonym of Steinera molybdoplaca , but this does not imply that P. glaucella should be considered as the type species of the genus Steinera as has been stated by Henssen & James (1982), in particular as Steinera glaucella is a species different from Zahlbruckner’s concept of Steinera molybdoplaca . Therefore, we conclude that the correct type species of the genus Steinera is S. molybdoplaca (Nyl.) Zahlbr. , as has been cited for instance by Keuk (1977).

The following taxonomic treatment does not take into account the infraspecific taxa.