Flora of North America species comparison

The sporophytes of Sphagnum wulfianum are moderately common. This is the most dry-growing species in North America, typically growing in association with Sphagnum centrale, S. girgensohnii, S. russowii, and S. squarrosum. It is easily recognized as the only species that regularly has more than six branches per fascicle. The Lycopodium clavatum-like growth habit and conifer swamp habitat along with the strongly 5-ranked branch leaves make it even easier to recognize in the field.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The compact growth form in thin but dense mats and occurrence in often dessication-prone sites distinguishes Sphagnum perichaetiale from any other species of sect. Sphagnum. The often quite stiffly spreading branch leaves give it a strong resemblance to S. compactum, but the latter’s small triangular stem leaves will readily distinguish that species. The branch leaf hyaline cells of S. perichaetiale have only a few pores on their convex surface, and they are typically small, thickened, and grouped in 3s where the cell corners meet. Similar species in sect. Sphagnum have more pores along the commissures, and they are more elliptical and not thickened. The often hemiisophyllous stem leaves are also diagnostic of S. perichaetiale within the section.

(Discussion copyrighted by Flora of North America; reprinted with permission.)