## 3 Discussion  
One of our goals was to identify the cyanbiont co-existing with _A. filicuoides_. Given the contrasting information from the literature, this issue is still not completely clear. In the study by [PERSON] and [PERSON] [16], deep screening of the classification and phylogeny of the cyanbiont was carried out. The existing controversy over its classification is associated with the method applied. In addition, co-evolution between the cyanbiont and the _Azolla_ host is possible as well as the existence of more than one genus or more than one species strain. This could explain the different classifications originating from molecular and botanical analysis. Although many publications traditionally name this cyanobacteria _Anabaena azolae_ or _Nostoc azolae_[10], likewise new publications [26], [PERSON] and \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Isolate**} & \multicolumn{2}{c}{**P mineralization**} & \multicolumn{2}{c}{**P solubilization**} & \multicolumn{2}{c}{**Siderophores**} \\ \cline{2-7}  & **h \({}^{1}\) (cm)** & hc \({}^{2}\) & **h (cm)** & **hc** & **h (cm)** & **hc** \\ \hline _Staphylococcus_ sp. & & & & & & \\ AzoEndo11 & 0.26 (0.19) & 0.23 (0.17) & 1.95 (0.72) & 1.91 (0.93) & n/a \({}^{3}\) & n/a \\ _Microoccus_ sp. AzoEndo14 & 0.39 (0.08) & 0.32 (0.12) & 0.29 (0.44) & 0.64 (0.62) & n/a & n/a \\ _Bacillus_ sp. AzoEndo3 & 0.62 (0.18) & 0.47 (0.18) & 1.15 (0.54) & 1.35 (0.43) & 3.56 (0.17) & 10.10 (1.79) \\ _Acinetobacter_ sp. AzoEndo8 & 0.31 (0.10) & 0.25 (0.09) & n/a & n/a & n/a & n/a \\ \hline _Achromobacter_ sp. AzoEpi1 & 0.36 (0.09) & 0.33 (0.11) & n/a & n/a & 0.56 (0.29) & 0.07 (0.04) \\ _Bacillus_ sp. AzoEpi2 & 0.52 (0.18) & 0.43 (0.15) & n/a & n/a & n/a & n/a \\ _Delftia_ sp. AzoEpi7 & 0.49 (0.19) & 0.43 (0.16) & 0.79 (0.29) & 1.01 (0.39) & 0.98 (0.21) & 0.64 (0.10) \\ _Aclaligenes_ sp. AzoEpi21 & 0.35 (0.13) & 0.31 (0.13) & n/a & n/a & 0.10 (0.00) & 0.39 (0.15) \\ _Microobacterium_ sp. AzoEpi23 & 0.46 (0.13) & 0.43 (0.15) & n/a & n/a & n/a & n/a \\ _Agrobacteriumium_ sp. AzoEpi25 & 0.43 (0.13) & 0.39 (0.15) & n/a & n/a & 0.41 (0.14) & 0.17 (0.06) \\ \hline \end{tabular}  
\({}^{1}\) h—halo size; \({}^{2}\) hc—halo-to-colomy size ratio; \({}^{3}\) n/a—no positive reaction.  
\end{table} 
Table 5: Levels of IAA as well as cellulase and protease activities of studied isolates (means\(\pm\)SD). [PERSON] [27] renamed it to _Trichormus azolae_. The results reported by [PERSON] and colleagues [15] are consistent with the latter study. In addition, most of non-plankton species of _Anabeana_ without gas vacuoles are now included in _Trichormus_. All planktonic species with gas vacuoles retain their classification into _Anabeana_. The difference between the two genera, _Trichormus_ and _Anabeana_, as presently understood, is related to the developmental relationships between the heterocysts and spores [28]. The botanical observation carried out in this study revealed these traits, allowing a conclusion that T. azolae is the cyanobient. It is also convincing that the AlgaeBase states that _A. azolae_ is currently regarded as a synonym of _T. azolae_[29]. The main goal in our study was to detect and identify cultured microbiome of _A. filiculoides_. Previous studies mentioned the presence of bacterial endosymionts within fern's cavities; yet, they have not been identified. This could be attributed to insufficient identification tools available at that time, whereas many modern tools are available now. Studies conducted by [PERSON] et al. and [PERSON] [19; 20] typed some bacterial genera: _Pseudomonas_, _Alcaligenes_, _Caulobacter_, and _Arthobacter_. [PERSON] and [PERSON] [18] presented a description of 5 different microorganisms, i.e., both G+ and G- bacteria inhabiting leaf cavities of _A. caroliniana_. All these studies were based on the use of biochemical and microbiological tests for describing these microorganisms. Nevertheless, none of them employed any molecular analysis for identification of bacteria.