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Introduction
The second largest group of terrestrial plants, commonly known under the joint name bryophytes (Plantae, subkingdom Bryobiotina) has traditionally been divided into liverworts (class Hepaticae), hornworts (class Anthocerotae) and mosses (class Musci). Lately, based on morphological, molecular and phytochemical evidences, the bryophytes (sensu lato) are now divided into three phyla, viz. Bryophyta (comprising mosses, including peat mosses, lantern mosses, haircap mosses), Marchantiophyta (liverworts, both leafy as well as thalloids) and the Anthocerotophyta (hornworts). Besides being diverse, all bryophytes share the same features of having dominant haploid green photosynthetic phase and lack the key steps towards lignin formation (Weng and Chapple, 2010). Thus, bryophytes are also known as non-vascular plants (atracheophytes), as opposed to vascular plants (tracheophytes) that produce lignin to support their cell wall. Bryophytes occur in all ecosystems except in salt water, although some species inhabit salt rich environment often referred as halophytic bryophytes (Riella sp., Entosthodon hungaricus (Boros) Loeske, Hennediella heimi (Hedw.) Zander). For some non-halophytic species such as Physcomitrella patens (Hedw.) Mitt., it was shown that it could grow well in liquid media with 1.5% salt concentration in laboratory conditions (King et al., 2016).
The species richness within bryophytes comprises up to 24,000 species worldwide (Hallingbäck and Hodgetts, 2000). However, due to many discoveries of new species and synonymization of others every year, the number of taxa keeps changing.
Bryophytes are known to be pioneers and quick settlers of empty spaces (Ingimundardottir et al., 2014). They usually compete with lichens for spaces but cannot compete with vascular plants. Bryophytes are still found in microhabitats in every ecosystem and play significant role in each of them, like in nutrient cycling, water economy or providing shelter for other organismal groups to survive harsh periods and reproduce. Although some animals do consume bryophytes, it is generally accepted that due to their interesting chemical constituents, they are usually avoided by animal herbivores. Likewise, some birds, insects and snails will usually change to vascular plants when given the opportunity (Ingimundardottir et al., 2014).
The size of bryophyte species varies from few millimeters in liverwort Monocarpus to 0.7 m in the self-supporting Dawsonia superba Grev., and 2 m as observed in the water habitat supported Fontinalis antipyretica Hedw.
The reason for this is...