Syzygiella trigonifolia (Stephani, 1902) Herzog, 1934

Váňa, Jiří, Feldberg, Kathrin, Söderström, Jochen Heinrichs Lars, Hagborg, Anders & Konrat, Matt Von, 2014, Notes on Early Land Plants Today. 55. New taxa and synonyms in Adelanthaceae (Marchantiophyta), Phytotaxa 173 (1), pp. 80-86 : 82

Syzygiella trigonifolia

The combination Syzygiella trigonifolia ( Stephani1902b: 863) Herzog (1934:87) was made without citing the basionym. Inoue (1966) interpreted the possible basionym to be Plagiochila trigonifolia Steph. but his opinion was probably influenced by the fact that he was an expert on the genus Plagiochila ( Dumortier 1831: 42) Dumortier (1835: 14) . However, Herzog (1934) wrote “Diese Art vermittelt zwischen Jamesoniella und Syzygiella , steht aber letzterer näher, so dass eine Versetzung in diese Gattung berechtigt erscheint“ (“This species is intermediate between Jamesoniella and Syzygiella , but is more closely to the latter, therefore a transfer to this genus seems justified”). In contrast to Inoue´s (1966) opinion, Grolle (1971) accepted Syzygiella trigonifolia as a synonym of Jamesoniella trigonifolia Stephani (1916: 185) which corresponds to Herzog’s description. Jamesoniella trigonifolia was synonymized by Grolle (1971) with Plagiochila fuscolutea Taylor (1846: 263) , and already Herzog (in sched.) had noted “ob nicht Form von Pl. fuscolutea ”. Heinrichs (2002) excluded Jamesoniella trigonifolia from the synonymy of Plagiochila fuscolutea and placed it in the synonymy of Syzygiella anomala (Lindenb. et Gottsche in Gottsche et al. 1847: 646) Stephani (1902a: 471), accepting forms with subopposite as well as opposite leaves in this taxon and noting that “a specimen from Tablas (Herzog 2915) was accepted as Syzygiella anomala by the monographer of the genus ( Inoue 1966)”. Reconsidering molecular and morphological evidence ( Feldberg et al. 2010a), we find that the above forms belong to different species, namely Syzygiella anomala and Syzygiella liberata Inoue (1974: 301) . Syzygiella liberata differs from Syzygiella anomala in having broadly triangular rather than elongate triangular leaves with a recurved dorsal leaf margin, and, most importantly, laterally compressed, dorsally subopposite leaves, while Syzygiella anomala has leaves which are regularly spreading and adnate dorsally and ventrally. Syzygiella liberata also shows a stronger tendency to produce rhizoids at the ventral leaf bases. The latter species was not treated in Inoue (1966), hence his determination key leads to Syzygiella anomala . The type material of Jamesoniella trigonifolia matches the morphology of Syzygiella liberata ; hence, we place Syzygiella liberata in the synonymy of the older taxon, Syzygiella trigonifolia .