Favoritos de syrinxed

Growing atop a small white (likely calcareous) boulder submerged in damp leaf litter.

The form is different from how it looks in photos online...but the smaller characteristics (that I could actually see) and sporophyte characteristics match quite well. I'd appreciate some input :)!

Leaves very small, below 0.25 mm. Entire margins. Lanceolate to ovate. Apex acute to acuminate / Laminal cells rhomboidal & rounded, not papillose, arranged symmetrically / Alar cells few, not easily discernable / Seta ~8mm, twisted, smooth / Capsules inclined; green, short, and plump / Peristome teeth yellow

Polytrichum commune var. uliginosum: elongate stems, tightly sheathing glossy leaf bases, leaves flexuose and recurved.
In this individual: marginal lamellae deeply notched to flat to rounded, lamellae 3-6 cells high

Genetic analysis suggests var. uliginosum is a separate lineage from var. commune:
https://onlinelibrary.wiley.com/doi/abs/10.1055/s-2000-5952

Growing unintentionally on artificial light, floating on a mass of rhizoids on water and attached to the intake filters in PetSmart fish tanks. Microscope photos show plantlets growing from gemmae, leaf shape, apical and axial gemmae with leaf primordia, and rhizoids. Plants strongly hydrophobic.