Sphagnum

Ignatov, M. S., Lamkowski, P., Ignatova, E. A. & Perkovsky, E. E., 2019, Mosses from Rovno amber (Ukraine), 4. Sphagnum heinrichsii, a new moss species from Eocene, Arctoa 28 (1), pp. 1-11 : 2

Genus Sphagnum L. gen. nov. [order Sphagnales , family Sphagnaceae ]

Type species: Sphagnum palustre L., extant .

Diagnosis: Single layered laminal cells dimorphous: narrow chlorocysts form loops embracing hyalocysts forming a regular cell network of which the latter have conspicuous fibrils and often also pores.

Comment: Sphagnum (and related genera, recently segregated from Sphagnum , but similar, so previously placed in this genus), have many features unique for bryophytes in both sporophyte and gametophyte structure. Here we mention only a character which is easy to observe even in a small leaf fragment, and therefore alone is sufficient to refer a specimen to the order Sphagnopsida. Until recently this order was treated as containing the only genus Sphagnum , however phylogeny reconstruction ( Shaw et al., 2010b) revealed ancient groups, segregated in two families with three genera: Flatbergiaceae ( Flatbergium ), and Ambuchananiaceae ( Ambuchanania and Eosphagnum ). Two latter genera are characterised by strongly concave, not acuminate and usually blunt branch leaves, very different from our amber specimen. Flatbergium has completely efibrillose hyalocysts thus not worthy further enumeration of numerous distinctions.