Sphagnum papillosum P21 Identification Card
Robust and tumid (similar to S. palustre and sometimes difficult to diatinguish from that species in the field); typically rather short, pale ochre-brown throughout, though commonly green or yellowish; capitulum often brown but never red. A common and widely distributed species of open acid peatlands, growing in distinct hummocks or more extensive carpets and often the principal peat former.
This is the dichotomous key with which the P21 culture was analyzed.
The images shown were made to the optical microscope by analyzing samples taken from culture P21.
For the full dichotomous key, read this blog
Cortical cells or branches (and usually at least the internal one of stems) with spiral fibrils. Apices of branch leaves blunt and hooded, appearing minutely roughened. On the convex surface due to projecting, partly resorbed, hyaline cells. Plants usually robust.
Cortical cells without fibrils. Branch leaf apices usually acute, truncate or, if hooded, then smooth on the convex surface. Plants robust or small.
Fig. 1 - The spirals fibrils, which are present in cortical cells of the stem of the branches, are well evident.
Fig. 2 - Apices of branch leaves blunt and hooded, appearing minutely roughened. On the convex surface due to projecting, partly resorbed, hyaline cells.
Internal commissural walls of branch leaf hyaline cells (at least in the lower lateral parts of leaves) with papillae or sparse to dense lamellae or crests (ie appearing as though the photosynthetic cells have papillose or ornamented walls). Plants green, yellow, ochre or brown, never crimson.
Internal commissural walls smooth throughout. Plants, except for capitula, usually green or crimson-tinted.
Fig. 3 - Internal commissural walls of branch leaf hyaline cells with papillae.
Fig. 4 - Photosynthetic cells well exposed on the concave leaf surface: in TS, trapezoid to narrowly oval-triangular.
Internal commissural walls finely to rather coarsely papillose. Photosynthetic cells in TS, urn-shaped with oval lumina and thick adaxial walls. Plants often ochrous: widely distributed and locally abundant on oligotrophic to slightly mesotrophic mires.
Internal commissural walls with scattered dense, oblique to transverse crests or lamellae ('comb fibrils'). Photosynthetic cells in TS, broadly triangular with triangular lumina: thin-walled. Plants dull brown to orange-brown, rarely green or yellowish: local to rare in, mainly lowland, oligotrophic to slightly mesotrophic mires.
Fig. 5 - Large and robust Capitula