It is a circumpolar peat moss found in arctic and subarctic regions of Europe and Asia, with populations also occurring in North America.

The species typically grows in loose mats in wet, moderately nutrient-rich environments, particularly in areas dominated by sedges and locations that experience seasonal flooding.

Although widely distributed and classified as a least-concern species globally, it faces varying levels of conservation concern across its range, being critically endangered in several European countries due to habitat degradation, peat extraction, and climate change.

The species is distinctive among peat mosses for its poorly developed capitula with protruding stem buds, and its dioecious reproduction, with male plants and spore-producing structures being rare in many regions.

While most populations are gametophytically haploid (having a single set of chromosomes in the dominant life phase), allodiploid plants with fixed heterozygosity have been documented in northern Quebec.

The species shows ambiguous phylogenetic relationships with other members of the Pacific Rim clade, possibly reflecting ancient hybridisation events in its evolutionary past.

Unlike many other peat mosses, this species has poorly developed capitula (the dense cluster of branches at the plant's tip) with distinctive large, oval stem buds protruding from them.

When stained for microscopic examination, these outer cortical cells often reveal a single large pore or thinned area in their walls.

The central part of the stem (internal cylinder) is pale to light brown in colour, never developing the dark or blackish-brown hue seen in some related species.

[4] Sphagnum platyphyllum typically grows in loose mats in wet environments that are moderately nutrient-rich (mesotrophic) to slightly nutrient-enriched (mildly eutrophic).

It shows a particular affinity for areas dominated by sedges (Carex species) and locations that experience seasonal flooding, such as the margins of pools, rivers, and lakes, as well as in fens.

Throughout Europe, the species shows a predominantly north-eastern distribution pattern, reaching its greatest abundance in Scandinavia whilst extending as far south as Portugal and Bulgaria.

These include the degradation of mire ecosystems through human development, peat extraction activities, habitat fragmentation, and changes in groundwater levels resulting from drainage operations.