Opuscula Philolichenum, 11: 19-25. 2012. *pdf available online 3January2012 via (http://sweetgum.nybg.org/philolichenum/) The name Myriospora is available for the Acarospora smaragdula group 1 2 LINDA IN ARCADIA & KERRY KNUDSEN ABSTRACT. – The name Myriospora Nägeli ex Hue (1909) is not legitimate, because of its earlier validation by Uloth (1861). The name Myriospora Nägeli ex Uloth (1861) is here typified on M. smaragdula (Wahlenb. ex Ach.) Nägeli ex Uloth. The names Silobia M. Westb. & Wedin and Trimmatothelopsis Zschacke which have been used for the Acarospora smaragdula group, are placed in synonymy with Myriospora as circumscribed here. Seven new combinations are made in Myriospora: M. dilatata (M. Westb. & Wedin) K. Knudsen & L. Arcadia, M. hassei (Herre) K. Knudsen & L. Arcadia, M. myochroa (M. Westb.) K. Knudsen & L. Arcadia, M. rhagadiza (Nyl.) K. Knudsen & L. Arcadia, M. scabrida (Hedl. ex H. Magn.) K. Knudsen & L. Arcadia, M. tangerina (M. Westb. & Wedin) K. Knudsen & L. Arcadia, and M. versipellis (Nyl.) K. Knudsen & L. Arcadia. The new genus Caeruleum K. Knudsen & L. Arcadia is described to accommodate the species previously placed in Myriospora, necessitating two new combinations: C. heppii (Nägeli ex Körb.) K. Knudsen & L. Arcadia and C. immersum (Fink) K. Knudsen & L. Arcadia. INTRODUCTION The genus Myriospora Hepp, long treated as a synonym of Acarospora A. Massal., was resurrected by Harris (2004) to accommodate Myriospora immersa (Fink) R. C. Harris. Harris and Knudsen (2006) pointed out that the question of whether the name Myriospora was validly published by Hepp (1853) depends on whether or not fascicles 1 and 23 of Hepp's exsiccata Flechten Europas were published simultaneously. Harris and Knudsen (2006) argued that these fascicles were indeed published simultaneously. We agree with this conclusion, and with the fact that Myriospora was not validly published by Hepp (1853). Recognizing that Myriospora was not validly published by Hepp (1853), Harris and Knudsen concluded that the name was validated by Hue (1909). Unfortunately, they overlooked a much earlier validation of the name by Uloth (1861: 617). The relevant passage reads: "Myriospora Näg. Apothecia fast krugförmig. Sporen einzellig, eiförmig oder elliptisch, in grosser Anzahl in einem Schlauch." This description, though brief, is enough for valid publication of the name Myriospora Nägeli ex Uloth. As a result, Myriospora Nägeli ex Hue is a later homonym, and not legitimate. Uloth validly published three names at species rank in Myriospora as follows: 1) Myriospora macrospora (A. Massal. ex Bagl.) Hepp ex Uloth – Uloth introduced the name without any reference to Baglietto and as though it were a new name at the species rank for Lecanora cervina β castanea e. scutellaris Schaer. (1850: 55), which Uloth cited in synonymy. In other words, its type is the type of Schaerer's name. When Baglietto (1857: 396) published the name Acarospora 1 LINDA IN ARCADIA – Kastri, 22013 Arkadias, Greece. – e-mail: [email protected] 2 KERRY KNUDSEN – The Herbarium, Department of Biology and Plant Sciences, University of California, Riverside, CA 92521, U.S.A. – e-mail: [email protected] 3By "fascicle 1" Harris and Knudsen meant Band 1, Heft 1 -- 2, and by "fascicle 2" they meant Band 1, Heft 3 -- 4; see Sayre (1969). 19 macrospora he did so in a way that also typified it on L. cervina β castanea e. scutellaris Schaer. The name M. macrospora can be regarded as a combination from A. macrospora A. Massal. ex Bagl. 2) Myriospora rufescens (Ach.) Hepp ex Uloth – This name was based, via Lecanora cervina γ rufescens (Ach.) Schaer. (1850: 56) and Lecidea rufescens (Ach.) Borrer in Hooker & Sowerby (1831: tab. 2657), on Sagedia rufescens Ach. (1810: 329). This is treated today as Acarospora rufescens (Ach.) Zwackh (in Flora 45: 482. 1862, where in our view the name is validly published, though the combination is often ascribed to Bausch (1869)) or in a segregate genus as either Silobia rufescens (Ach.) M. Westb. & Wedin or Trimmatothelopsis rufescens (Ach.) Cl. Roux & Nav.-Ros. 3) Myriospora smaragdula (Wahlenb. ex Ach.) Nägeli ex Uloth – This name was based, via Acarospora sinopica var. smaragdula (Wahlenb. ex Ach.) Körb. (1855: 156), on Endocarpon smaragdulum Wahlenb. ex Ach. (1803: 29-30). (Authorship of the basionym is cited correctly under the Vienna Code: see Arcadia (2010). However, the Melbourne Code may adopt different rules; authorship may become Wahlenb.) This is treated today as Acarospora smaragdula (Wahlenb. ex Ach.) A. Massal. or in a segregate genus as either Silobia smaragdula (Wahlenb. ex Ach.) M. Westb. & Wedin or Trimmatothelopsis smaragdula (Wahlenb. ex Ach.) Cl. Roux & Nav.-Ros. Uloth did not designate a type species when he validated Myriospora. Harris and Knudsen (2006) typified Myriospora Nägeli ex Hue on M. heppii (Nägeli ex Körb.) Hue, based on Acarospora heppii Nägeli ex Körb. (1859) (not "1865" as stated by Harris and Knudsen, because pages 1-96 of Körber's Parerga Lichenologica were published in 1859). However, that name is neither one of those included by Uloth in Myriospora, nor is it synonymous with any of Uloth's species. Unless we resort to conservation, which does not seem appropriate here, Myriospora Nägeli ex Uloth must be typified on one of the three species listed above. The first of Uloth's species falls within the present circumscription of Acarospora, but the other two were recently placed in the new genus Silobia M. Westb. & Wedin. Thus there are two options: either typify the name Myriospora on M. macrospora, which would make Myriospora a synonym of Acarospora, at least for the present, or typify the name on M. rufescens or M. smaragdula. Because two of Uloth's three species belong to the A. smaragdula group, we consider the second option to be preferable and we here typify Myriospora on M. smaragdula (Wahlenb. ex Ach.) Nägeli ex Uloth, the more common of the two species. The genus Silobia M. Westb. & Wedin, which was published by Westberg et al. (2011), is typified on S. smaragdula, the same species, so the name Silobia automatically becomes a synonym of Myriospora. Roux and Navarro-Rosinés (2011), typifying the smaragdula group, including S. smaragdula, on Trimmatothelopsis versipellis (Nyl.) Zschacke, made Silobia a synonym of Trimmatothelopsis Zschacke. We agree that T. versipellis belongs in Myriospora and the name Trimmatothelopsis is also a synonym of Myriospora. This resolves the debate between Westberg and Wedin (2011) and Roux and Navarro-Rosinés (2011) over the correct generic name for the smaragdula group. The generic concepts and the species concepts we accept here are based exclusively on Westberg and Wedin’s excellent revision of the smaragdula group (Westberg et al. 2011). All the recognized members of the smaragdula group (Westberg et al. 2011, Knudsen 2011, Roux & Navarro-Rosinés 2011) are now here transferred to Myriospora. The second author has studied the type of Verrucaria versipellis Nyl. It has a high hymenium (180-200(-220) μm in height) in elevated parathecial crowns (i.e., an expanded true exciple elevated above the thallus surface). The parathecium of the elevated crowns is 70-100+ μm thick in the sections measured. The parathecial crowns can clearly be seen in the color picture of the type published by Westberg and Wedin (2011). This high hymenium height was originally observed in the type by Roux and Navarro- Rosinés (2002), though they did not recognize the character of parathecial crowns in their analysis. The higher hymenium and elevated parathecial crowns suggest a taxon more closely related to the Acarospora scabrida lineages, and more specimens of V. versipellis might be found among Mediterranean, central European or British specimens identified as A. scabrida. Such specimens would have a scabrid disc which is more punctiform than the dilated discs in A. scabrida s. str. Because of the higher hymenium and elevated parathecial crowns, we reject S. rhagadiza (Nyl.) M. Westb. as a synonym of V. versipellis as proposed by Roux and Navarro-Rosinés (2011). We are also concerned that their revised description of V. versipellis in the same paper is not based solely on the type, which based on annotations they have not seen since 2002. For the same reasons (height of hymenium and presence of parathecial crowns) we reject the 20 synonymy of the forms of A. scyphulifera with V. versipellis proposed by Roux and Navarro-Rosinés (2011) and instead accept the synonymy of these forms with A. rhagadiza in Westberg et al. (2011). It should be noted that without explanation, Roux (2007) separated A. versipellis from A. scyphulifera in his Acarospora key, which was published between Roux and Navarro-Rosinés (2002, 2011), thus agreeing with us for at least the period from 2007 to 2011. The black scabrid discs of the type of Verrucaria versipellis (with some ontogenic thalline remnants persisting as an umbo on some apothecia) as well as the parathecial crowns (which, in addition to probably being naturally somewhat melanized, appear to have been melanized much further by interactions with the substrate and with cyanobacteria) gave Westberg and Wedin (2011) the impression that a lichenicolous fungus was growing on the areoles of a brown Acarospora. We disagree with their interpretation of this material and thus reject the synonymy of V. versipellis with Polysporina subfuscescens (Nyl.) K. Knudsen & Kocourk. The monophyletic nature of the smaragdula group was well-supported in the molecular phylogenetic analyses of Wedin et al. (2009). Myriospora heppii is not a member of the smaragdula group; it differs in having a tholus staining blue in Lugol’s iodine after pre-treatment with potassium hydroxide (Harris & Knudsen 2006; Knudsen 2007). Initial molecular results tentatively place it in an isolated position in the Acarosporaceae (Westberg, pers. comm., 2011). We thus erect the new genus Caeruleum K. Knudsen and L. Arcadia which we typify on C.