Ignatov, M.S., T.V. Voronkova, A.S. Kartasheva & U.N. Spirina. 2021. On the branch primordia in Neckera and related genera (Bryophyta)

Arctoa (2021) 30: 434–450

doi: 10.15298/arctoa.30.29

Foliose and filamentose structures around branch primordia in Neckera and related genera were described by different authors using different terms. This study applied both morphological and physiological criteria to elucidation homology of structures around dormant branch buds. An effect of exogenous abscisic acid was studied on Exsertotheca crispa, and morphological studies were conducted on species of Neckera with and without paraphyllia. A specifics of Neckeraceae is that the dormant branch buds are large and not very clearly delimited. Proximal branch leaves are often spaced from the inner part of primordium and subdivided into 2–4 separate parts, which are very similar to paraphyllia. However, unlike paraphyllia, the proximal branch leaves are defined as descendants of branch apical cell, possess phylotaxis and are arranged in a pellucid zone around branch primordium. A large size of dormant branch buds in Neckera and related genera is associated or maybe even defined by shape of the apical cell. The apical cell is relatively small and more deeply sinked in the stem tissue than in most other pleurocarpous mosses. The homology and terminology of various foliose and filamentose structures around branch primordia are discussed.