Frullania

Hentschel, Jörn, Konrat, Matt Von, Söderström, Lars, Hagborg, Anders, Larraín, Juan, Sukkharak, Phiangphak, Uribe, Jaime & Zhang, Li, 2015, Notes on Early Land Plants Today. 72. Infrageneric classification and new combinations, new names, new synonyms in Frullania (Marchantiophyta), Phytotaxa 220 (2), pp. 127-142 : 129-131

Frullania (subg. Chonanthelia ) sect. Pluricarinatae (Yuzawa, Mues et S.Hatt.) Hentschel et von Konrat, comb.

nov. Basionym:— Frullania ser. Pluricarinatae Yuzawa, Mues et S.Hatt., J. Hattori Bot. Lab. 63: 428, 1987 ( Yuzawa et al. 1987). Type (ICN Art. 22.6):— Frullania pluricarinata Gottsche (1864: 168) .

Note:—The new section is created to host the taxa Hentschel et al. (2009) erroneously referred to F. sect. Chonanthelia as we have not been able to find any existing sectional name that can be applied.

Frullania subg. Diastaloba Spruce, Trans. & Proc. Bot. Soc. Edinburgh 15: 55, 1884 ( Spruce 1884). Lectotype (Hattori 1982: 235):— Frullania subtilissima (Nees ex Montagne 1840: 333) Lindenb. in Gottsche et al. (1845: 443).

Note:—This subgenus is characterized basically by the shape, position and orientation of the leaf lobule ( Spruce 1884). According to the molecular data at hand, the subgenus includes at least four genetically distinct lineages, provisionally named “ Diastaloba I–IV” ( Hentschel et al. 2009). Furthermore, the Diastaloba -like habit reoccurs in F. subg. Microfrullania, which makes the discrimination between both subgenera even more challenging ( Schuster 1992). Although much progress has been made towards a refined circumscription of F. subg. Microfrullania (e.g., von Konrat et al. 2006, Hentschel et al. 2009, von Konrat et al. 2010, 2011a, 2012, 2013), the taxonomic problems concerning the classification of F. subg. Diastaloba have not yet been satisfactorily solved. Frullania subg. Diastaloba was typified by Hattori (1982) with F. subtilissima , a rare and enigmatic species from Guyana. Based on preliminary observations, including the study of relevant type specimens, a morphological characterization of the corresponding lineages seems possible. A taxonomical revision is currently underway and will lead to an extensive reclassification of this by far most complex subgenus. We hereby recognize the four informal clades that correspond to “ Diastaloba I, II, III and IV” and have attempted to place species within these units for the forthcoming worldwide liverwort checklist (Söderström et al., in press). Not all purported taxa of these groups have been investigated using molecular tools. However, attempted groupings have been made based on morphological similarity and purported relationships described by previous workers, especially the many publications by S. Hattori on the genus. Since we do not yet know in which of the four lineages the type, F. subtilissima , belongs, we refrain from giving them formal sectional names. Below a brief discussion of these four natural units is presented.

Diastaloba I corresponds to three well supported clades which in Hentschel et al. (2009) included the type species of F. sect. Graciles Verdoorn (1930: 110) [type F. gracilis ( Reinwardt et al. 1824: 221) Nees in Gottsche et al. (1845: 452)], F. sect. Serratae Verdoorn (1930: 85) [type F. serrata Gottsche in Gottsche et al. (1845: 453)] and F. sect. Inconditum von Konrat et al. (2010: 480) [type F. hodgsoniae von Konrat et al. (2010: 492) ] (as Rostratae ). Although not included in any molecular study, F. sect. Vaginatae Verdoorn (1930: 141) [type F. vaginata ( Swartz 1781: 35) Dumortier (1835: 13) ], F. subsect. Ternatenses Hattori (1976: 466) [type F. ternatensis Gottsche in Gottsche et al. (1846: 465)], F. sect. Sinuatae Schuster (1985: 371) [type F. sinuata Sande Lacoste (1854: 424) ], F. sect. Pycnophyllae Schuster (1985: 370) [type F. pycnophylla Hattori (1973a: 60) (= F. curvistipula Stephani (1911: 541) ] and F. sect. Curvistipulae Schuster (1991: 144) [type F. curvistipula ] seem to belong here.

Diastaloba II includes the type species of one section in Hentschel et al. (2009), F. sect. Lucidae Verdoorn (1930: 125) [type F.repandistipula Sande Lacoste (1854 [1855]: 422)]. Although not included in any molecular study, F. sect. Ocellatae Schuster (1985: 371) [type F. ocellata Hattori & Kamimura (1973: 531) ] seems to belong here.

Diastaloba III comprises two species from Madagascar, F. usambarana Schiffn. ex Stephani (1894: 160) and F. grossiclava Stephani (1910: 384) ; neither of these represent a type of any subgeneric taxon. We were not able to find any existing name that would be possible to apply on this group.

Diastaloba IV corresponds to a group of distinctive plants that have strong microphyllous branches and long, narrow lobules oblique to the stem, e.g., F. hypoleuca Nees in Gottsche et al. (1843: 471) and F. obcordata ( Lehmann 1834: 51) Lehm. et Lindenb. in Gottsche et al. (1845: 447) [= F. caulisequa ( Nees 1833: 373) Montagne (1839: 51) ]. As with the previous group, none of the taxa included by Hentschel et al. (2009) in this group is a type of any subgeneric taxon, and we have no existing name that we think may be applicable to it.

Frullania subg. Diversitextae (Kamim.) S.Hatt., J. Hattori Bot. Lab. 59: 154, 1985 ( Hattori & Lin 1985). Basionym:— Frullania subsect. Diversitextae Kamim., J. Hattori Bot. Lab. 24: 80, 1961 ( Kamimura 1961). Type (ICN Art. 22.6):— Frullania diversitexta Stephani (1897: 89) .

Note:—We treat F. subg. Diversitextae as circumscribed by Hattori & Lin (1985) as monotypic and including only F. diversitexta . Kamimura (1961) first diagnosed F. subg. Diversitextae as a subsection of subg. F. sect. Diastaloba. Hattori & Lin (1985) raised it to subgeneric rank recognizing its somewhat chimeric appearance; the combination of tuberculate perianths—a feature unique to F. subg. Frullania , and its otherwise Diastaloba -like habit. This species has not yet been included in a molecular study, and its phylogenetic position therefore remains unclear. Judging from a morphological point of view, especially the development of the first branch leaf and the first branch underleaf as well as the shape of the stylus, there are certain affinities with the “ Diastaloba I”-clade of Hentschel et al. (2009).

Frullania subg. Frullania, Trans. & Proc. Bot. Soc. Edinburgh 15: 8, 1884 ( Spruce 1884). Lectotype ( Evans 1918: 468):— Frullania major Raddi (1818: 9) , nom. illeg. (ICN Art. 52.1; earlier name included) ≡ Frullania dilatata ( Linnaeus 1753: 1133) Dumortier (1835: 13) .

Note:— Raddi (1818) included two species in his new genus Frullania , F. major ( Raddi 1818: 9) and F. minor Raddi (1818: 10) , both being illegitimate as they included earlier names. Raddi had Linnaeus’ (1753: 1134) synonymy confused treating the larger species [ F. tamarisci ( Linnaeus 1753) Dumortier (1835: 13) ] as F. minor and the smaller species [ F. dilatata ( Linnaeus 1753: 1133) Dumortier (1835: 13) ] as F. major . Evans (1918: 468) was the first to select a type. He selected F. dilatata which was included as a synonym of F. major in Raddi (1818). It is often argued that Evans used the American Code and thus that the typification was mechanical, which is not allowed by the International Code (cf. ICN Art. 10.5(b)). However, in this case he did not choose the species first mentioned by Raddi, but a synonym of it, and thus it cannot be a mechanical selection. Frye & Clark (1947: 736) lectotypified the genus with F. tamarisci . However, their synonymy included F. major , the only element of their synonymy possible to choose as lectotype. Thus, the lectotype of Frullania (and also the autonym) is F. major which has long been treated as a synonym of F. tamarisci (e.g., Frye & Clark 1947). Also, F. subg. Frullania was used for what is now F. subg. Thyopsiella while what we currently accept as F. subg. Frullania used to be named F. subg. Trachycolea Spruce (1884: 31). Frullania subg. Frullania accommodates about 250 accepted species and represents one of the most specious subgenera of Frullania , especially in the extratropical regions, and includes a large number of polymorphic species ( Hentschel et al. 2009). The further subdivision in a number of sections and subsections as well as the occurrence of many rather polymorphic species makes this subgenus taxonomically fairly difficult ( Schuster 1992, Hentschel et al. 2009). Hence, it is not surprising that the group remains unrevised on a global scale. Yuzawa (1991) regarded species of F. subg. Frullania as being closely related to species of F. subg. Chonanthelia , but the lineage proved to be distinct based on the morphological and molecular data at hand (e.g., Schuster 1992, Hentschel et al. 2009). Although the analysis of Hentschel et al. (2009) is based on a rather large dataset, the taxon sampling is still inadequate to revise all sections and subsections, but it is obvious that the sectional and subsectional assignment for several taxa based on morphological evidence is not supported by the molecular data. Key taxa to be investigated include the missing type species of supraspecific entities, e.g., F. errans Verdoorn (1930: 59) , F. monocera ( Hooker & Taylor 1845: 89) Gottsche et al. (1845: 418) and F. ornithocephala ( Reinwardt et al. 1824: 216) Nees in Gottsche et al. 1845: 425, and more accessions of genetically complex species, like F. ericoides ( Nees 1833: 346) Montagne (1839: 51) , F. nepalensis ( Sprengel 1827: 324) Lehm. in Gottsche et al. (1845: 422), and F. fugax ( Hooker & Taylor 1845: 87) Gottsche et al. (1845: 445) . Despite strong evidence that some sections and subsections likely will become synonyms ( Hentschel et al. 2009), proposing formal synonymy now would only contribute to the already inflated sectional and subsectional classification due to some paraphyletic species such as F. ericoides Nees (1833: 346) Montagne (1839: 51) . However, a suite of subclades can be recognized at present and are therefore adopted for the forthcoming worldwide checklist.

Frullania (subg. Frullania ) sect. Acutilobae Verd., Ann. Bryol., Suppl. 1: 44, 1930 ( Verdoorn 1930). Lectotype (here designated):— Frullania monocera ( Hooker & Taylor 1845: 89) Gottsche et al. (1845: 418) .

Note:— Schuster (1992) noted that the form of gynoecial axes in this section should be investigated citing that typical members, e.g. F. allanii Hodgson (1949: 371) , bear gynoecia on unspecialised leafy axes that again branch, in contrast to the simple gynoecial branches of F. bonincola Hattori (1978: 551) , which is purportedly allied to the section. Kamimura (1961) noted that F. sect. Acutilobae is a weak taxon and that the acute rostrum of the leaf-lobules was the only significant difference between F. sect. Acutilobae and F. sect. Trachycolea. However, Hattori (1983) stated that F. sect. Acutilobae was unique with the long piliferous beaks of the leaf-lobules. The molecular analysis by Hentschel et al. (2009) supports this classification.

Frullania (subg. Frullania ) sect. Australes Verd., Ann. Bryol., Suppl. 1: 58, 1930 ( Verdoorn 1930). Lectotype ( Hattori 1976: 463):— Frullania errans Verdoorn (1930: 59) .

Note:— Verdoorn (1930) first established F. sect. Australes as a section within F. subg. Frullania (as F. subg. Trachycolea). Later Hattori (1976) made a new combination raising the rank of F. sect. Australes to subgenus. Hentschel et al. (2009) showed molecular evidence that F. subg. Australes forms a robust subclade and is nested within a polytomous topology with several sections of F. subg. Frullania . We therefore prefer Verdoorn’s (1930) treatment of F. sect. Australes as a section of F. subg. Frullania . The majority of species of this lineage is distributed in Eastern Asia and Australasia, but according to the Hentschel et al. (2009) phylogeny the neotropical F. glomerata and African F. obscurifolia Mitten (1879: 400) also belong here.