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Aim Scaly tree ferns, Cyatheaceae, are a well-supported group of mostly tree-forming ferns found throughout the tropics, the subtropics and the south-temperate zone. Fossil evidence shows that the lineage originated in the Late Jurassic period. We reconstructed large-scale historical biogeographical patterns of Cyatheaceae and tested the hypothesis that some of the observed distribution patterns are in fact compatible, in time and space, with a vicariance scenario related to the break-up of Gondwana. Location Tropics, subtropics and south-temperate areas of the world. Methods The historical biogeography of Cyatheaceae was analysed in a maximum likelihood framework using Lagrange. The 78 ingroup taxa are representative of the geographical distribution of the entire family. The phylogenies that served as a basis for the analyses were obtained by Bayesian inference analyses of mainly previously published DNA sequence data using MrBayes. Lineage divergence dates were estimated in a Bayesian Markov chain Monte Carlo framework using BEAST. Results Cyatheaceae originated in the Late Jurassic in either South America or Australasia. Following a range expansion, the ancestral distribution of the marginate-scaled clade included both these areas, whereas Sphaeropteris is reconstructed as having its origin only in Australasia. Within the marginate-scaled clade, reconstructions of early divergences are hampered by the unresolved relationships among the Alsophila, Cyathea and Gymnosphaera lineages. Never-theless, it is clear that the occurrence of the Cyathea and Sphaeropteris lineages in South America may be related to vicariance, whereas transoceanic dispersal needs to be inferred for the range shifts seen in Alsophila and Gymnosphaera. Main conclusions The evolutionary history of Cyatheaceae involves both Gondwanan vicariance scenarios as well as long-distance dispersal events. The number of transoceanic dispersals reconstructed for the family is rather few when compared with other fern lineages. We suggest that a causal relationship between reproductive mode (outcrossing) and dispersal limitations is the most plausible explanation for the pattern observed.

By studying the population structure and spatial characteristics, the relationship between tree‐ferns and the environment can be reflected, which has high practical significance. In this study, we employed an ensemble distribution model to evaluate the relative contribution of various environmental variables and predict suitable habitats for tree‐fern across past, present, and future periods. Fieldwork was carried out between May–June 2019 and September 2022 in 11 districts of Nepal for population sampling and collecting the geocoordinates. Additional geocoordinates were collected from secondary sources such as previous literature, herbarium records, and online resources. We reported the occurrence of tree‐ferns from 28 districts within the altitudinal range of 300–2500 m. Longitudinally, the species is distributed only in central and eastern Nepal, with maximum density in central Nepal's Kaski and Lamjung districts. The central mid‐hills of Koshi and Gandaki provinces, particularly with the moist habitats and maximum rainfall, are suitable for the distribution of tree‐ferns. The projected distribution is influenced mainly by the mean temperature of the coldest quarter—Bio11 (34.9%), precipitation in dry months—Bio14 (34.5%), and mean annual temperature—Bio1 (33.9%). Climate extreme variables (maximum temperature in warmest months—Bio5, minimum temperature in coldest months—Bio6, precipitation in wettest months—Bio13, precipitation in wettest quarter—Bio16) contract the future distribution of species. The result portrays an expansion of suitable habitat for tree‐ferns while minor contractions are predicted in four districts of Bagmati province. As the Gandaki province receives the highest rainfall and the Koshi province has rich soil moisture, and precipitation plays a significant role in distribution, humid riverine places of Koshi and Gandaki support tree‐fern populations. Tree‐ferns could be an indicator species of the moist and humid climate. Given the extensive distribution in Nepal, India, and China, sustainable conservation of tree‐ferns through a species conservation action plan holds broader implications. Tree‐ferns are distributed only in central and eastern Nepal with maximum density in Kaski and Lamjung districts, Central Nepal. This reveals that the central mid‐hills of Koshi and Gandaki provinces, particularly with the moist habitats and maximum rainfall areas, are suitable for tree‐ferns. The projected distribution is influenced mostly by the mean temperature of the coldest quarter—Bio11 (34.9%), precipitation in dry months—Bio14 (34.5%), and mean annual temperature—Bio1 (33.9%).

KEY MESSAGE : Somatic embryogenesis has never been reported in ferns. The study showed that it is much easier to evoke the acquisition and expression of embryogenic competence in ferns than in spermatophytes. We discovered that the tree fern Cyathea delgadii offers an effective model for the reproducible and rapid formation of somatic embryos on hormone-free medium. Our study provides cyto-morphological evidence for the single cell origin and development of somatic embryos. Somatic embryogenesis (SE) in both primary and secondary explants was induced on half-strength micro- and macro-nutrients Murashige and Skoog medium without the application of exogenous plant growth regulators, in darkness. The early stage of SE was characterized by sequential perpendicular cell divisions of an individual epidermal cell of etiolated stipe explant. These resulted in the formation of a linear pro-embryo. Later their development resembled that of the zygotic embryo. We defined three morphogenetic stages of fern somatic embryo development: linear, early and late embryonic leaf stage. The transition from somatic embryo to juvenile sporophyte was quick and proceeded without interruption caused by dormancy. Following 9 weeks of culture the efficiency of somatic embryogenesis reached 12–13 embryos per responding explant. Spontaneous formation of somatic embryos and callus production, which improved the effectiveness of the process sevenfold in 10-month-long culture, occurred without subculturing. The tendency for C. delgadii to propagate by SE in vitro makes this species an excellent model for studies relating to asexual embryogenesis and the endogenous hormonal regulation of that process and opens new avenues of experimentation.

Alsophila costularis Barker (Cyathea costularis), an endangered tree fern with tree-like erect stem, attracts gardening enthusiasts as a special ornamental plant. In vitro propagation can be advantageous for germplasm conservation and commercial application of A. costularis. Here, we described in vitro propagation of A. costularis via spore culture and green globular bodies (GGBs) system, as well as the long-term observation of acclimated plants regenerated from GGBs. In spore culture, the low concentration of mineral salt (1/8 MS) was beneficial for sporophyte formation on gametophytes, but sporophytes per conical flask was only 8 plantlets. In GGB system, cytokinin thidiazuron (TDZ) was essential for GGB induction and multiplication. The maximum of GGB induction frequency (93.33%) was obtained on 1/2MS medium with 2.0 mg/l TDZ by using juvenile sporophytes as explants, and the same medium was optimal for GGB multiplication. 1/4 MS supplemented with 0.1% (w/v) activated carbon (AC) was appropriate for plantlet regeneration from GGB, GGB differentiation frequency was 100%, and 42.40 plantlets could be regenerated from one piece of GGBs. The maximum of plantlet height (4.64 cm) was obtained on 1/2 MS with 0.1% (w/v) AC. After 6 years of acclimatization cultivation for plantlets regenerated from GGBs, plants in plastic pots with diameter of 60 cm showed an excellent vegetative and reproductive growth, and the mature spores of these plants could produce sporophytes. Morphological and histological observation demonstrated that A. costularis GGBs was a green structure that consisted of multiple single GGBs with hair-like structures. One single GGB could develop into one plantlet.Key messageEstablishment of an in vitro propagation protocol of endangered tree fern Alsophila costularis, and long-term observation of acclimated plants regenerated from green globular bodies (GGBs) in A. costularis.

Premise The entire life cycle of ferns has been documented, yet their life histories are still poorly understood. In particular, the phenology of fern gametophytes remains largely unknown. To address this issue, we demonstrated a new ecological approach to explore the phenological link between spore release and gametophyte maturation within the life history of a tree fern species. Methods We conducted a serial survey of Alsophila podophylla gametophyte abundance in the field, and recorded the time of its spore release. Every two months for one year, all terrestrial fern gametophytes in an unsampled subplot were collected and identified using tissue‐direct PCR. Results We found temporal differences in gametophyte abundances, with a sevenfold difference between the highest and lowest months. The number of spores released was linked to the gametophyte abundance two months later. The switch from gametophyte to juvenile sporophyte was found to be most correlated with precipitation. Discussion The observed fluctuation in gametophyte abundance and population structure was likely associated with the phenology of spore release and environmental factors. Importantly, these findings provide the first evidence of phenological links between different developmental stages in a fern's life history.

1. The experimental removal of early successional species can explain how plant communities change over time. 2. During a 7.3-year period, early successional woody species, scrambling ferns and tree ferns were removed from a total of 10 landslides in the Luquillo Experimental Forest in north-eastern Puerto Rico. 3. Early successional woody plants in combination with tree ferns decreased species richness and cover of forbs and increased richness of late-successional woody plants compared to removals, facilitating long-term forest development. 4. Dense stands of scrambling ferns decreased both forb and woody plant richness compared to removals, inhibiting forest development. 5. Stands of monospecific tree ferns initially increased woody plant richness compared to removals, but overall decreased woody plant richness and cover, inhibiting forest development. 6.Synthesis. Early successional species both facilitate and inhibit succession on tropical landslides, but detailed predictions of successional trajectories remain elusive and are influenced by stochastic processes including arrival order, the life-form of colonizing species and their competitive interactions.

Soil nitrogen and phosphorus pools shift strongly along soil chronosequences worldwide, but variation in plant nutrient resorption along these sequences is poorly understood. We quantified leaf and litter nutrient concentrations in 28 woody species along the Franz Josef soil chronosequence, New Zealand, a strong fertility gradient in temperate rain forest, to address two questions: How do leaf and litter nutrient concentrations vary along a soil chronosequence? And are the community-level responses driven by compositional differences among fertile and infertile sites, or by consistent changes in resorption proficiency within growth forms, and within species? Community-level leaf and litter N and P concentrations declined by between 67% and 88% along the soil chronosequence, and these responses were remarkably consistent within three contrasting growth forms (angiosperms, conifers, tree ferns), and within individual species. In spite of the three growth forms sharing similar responses to the soil chronosequence, tree ferns had higher absolute concentrations of leaf N, leaf P, and litter N relative to angiosperms, and higher concentrations of leaf N relative to conifers. These results clearly indicate that differences among fertile and infertile sites are driven both by compositional differences, as has been previously demonstrated, and by plasticity of individual species.

The scaly tree fern, Cyathea lepifera, in Taiwan has been devastated by an ascomycetous pathogen in recent years. This fungus resembles species of Diaporthe, but unlike anamorphs of Diaporthe that produce two types of conidia, its anamorph produces one conidium type. It is described herein as Ophiodiaporthe cyatheae gen. et sp. nov. Through pathogenicity tests, O. cyatheae was demonstrated to be the causal agent of the C. lepifera wilt disease. Of interest, sporulating structures of O. cyatheae have not been found on C. lepifera plants but in culture thus far. The mating system is homothallic. Phylogenetic analyses based on combined sequences of nSSU-rDNA, nLSU-rDNA, EF1-α-1 and RPB2 placed O. cyatheae in Diaporthaceae. Combined sequences of EF1-α-2 and TUB indicated that O. cyatheae had its origin within Diaporthe.

Cyatheaceae (tree ferns) appeared during the Jurassic period and some of the species still remain. Those species may have some morphological and/or physiological characteristics for survival. A tree fern was observed to suppress the growth of other ligneous plants in a tropical forest. It was assumed that the fern may release toxic substances into the forest floor, but those toxic substances have not yet been identified. Therefore, we investigated the phytotoxicity and phytotoxic substances of Cyathea lepifera (J. Sm. ex Hook.) Copel. An aqueous methanol extract of C. lepifera fronds inhibited the growth of roots and shoots of dicotyledonous garden cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), and alfalfa (Medicago sativa L.), and monocotyledonous ryegrass (Lolium multiflorum Lam.), timothy (Phleum pratense L.), and barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.). The results suggest that C. lepifera fronds may have phytotoxicity and contain some phytotoxic substances. The extract was purified through several chromatographic steps during which inhibitory activity was monitored, and p-coumaric acid and (-)-3-hydroxy-β-ionone were isolated. Those compounds showed phytotoxic activity and may contribute to the phytotoxic effects caused by the C. lepifera fronds. The fronds fall and accumulate on the forest floor through defoliation, and the compounds may be released into the forest soils through the decomposition process of the fronds. The phytotoxic activities of the compounds may be partly responsible for the fern’s survival.

Sixty fern species are considered problematic worldwide because of their invasiveness, but only two of them are tree ferns. This paper reports the invasion by the Australian tree fern Dicksonia antarctica to the eastern part of São Miguel Island (Azores archipelago—Portugal). It probably escaped from cultivation in the nineteenth century and has spread to an area of over 48 km 2 , mainly at high altitude (>500 m a.s.l.). The invaded area is characterized by high precipitation (mean = 2,857 mm/year), high relative humidity (mean = 96.4%), and mild temperatures (mean = 12.1°C). The species has invaded forest plantations, exotic forests and two habitats of European conservation priority: native laurel forests and blanket bogs. Dicksonia antarctica plantlets (individuals with no trunk) were predominant in exotic forests , D. antarctica shrubs (trunk height < 1 m) were most frequent in blanket bogs and forest plantations whereas trees (trunk height > 1 m) in gardens. Blanket bogs had the maximum percentage (90%) of fertile individuals (i.e. with sporangia). The large size and poor access of invaded area makes full eradication from the island impossible. We recommend complete elimination in blanket bogs and to take control measures in native laurel forests as these are priority conservation habitats.