Calliergon (Sullivant in A. Gray) Kindberg, 1894.


Key to Calliergon Etc.

In this key we treat pleurocarpous, costate mosses of wetland sites. The leaves typically have inflated alar cells, and they have bluntly rounded or obtuse and apiculate apices.

Species included in this key are in Campyliaceae:
Calliergon cordifolium (Hedwig) Kindberg, not known from CA
Calliergon giganteum (W. P. Schimper) Kindberg, not known from CA
Pseudocalliergon angustifolium Hedenäs
Pseudocalliergon trifarium (Weber & D. Mohr) Loeske, not known from CA
Pseudocalliergon turgescens (T. Jensen) Loeske, not known from CA
Straminergon stramineum (Dickson ex Bridel) Hedenäs
Sarmentypnum sarmentosum (Wahlenberg) Tuomikoski & T. Koponen, not known from CA

The species grouped here are all plants of wetland sites, often bogs and fens. Certain few characters seldom useful in other mosses must be emphasized here. All these species are to some extent decurrent but excised leaves of Calliergon sensu stricto show a triangular area of decurrency on each side such that the entire leaf base appears to describe a semi-circle.

"Nematogons" are cells of a leaf with the capacity to produce rhizoids. In Calliergon and its relatives those nematogons are best seen on each side of the tip of the costa. These nematogons appear as empty, somewhat enlarged single cells strongly contrasting with the more opaque neighboring cells.

A. Stem leaves with proximal one-half erect and nearly parallelling the stem but falcate and acuminate above that proximal base .....Pseudocalliergon: P. angustifolium
A. Stem leaves straight, erect to weakly spreading throughout, apiculate or rounded at apex .....B

B. Alar cells, including those of the extreme margin very thin-walled and strongly inflated; basal leaf margin broadly decurrent with that decurrency at least in part several cells wide; distal portion of leaves usually with a few nematogons .....C
B. Alar cells at least at basal margin rather thick-walled, less inflated than more interior alar cells; leaf margin narrowly or not at all decurrent; nematogons present or not .....E

C. Leaves elliptic, more than 2:1, with apex having a small apiculus; plants strongly washed with a reddish blush .....Sarmentypnum: S. sarmentosum not known from CA
C. Leaves broadly ovate to rounded deltoid with apex obtuse to rounded; plants green to brownish green .....D

D. Cells of alar region showing a gradual transition to the cells distal to that region; plants sparingly branched, not regularly pinnate .....Calliergon cordifolium not known from CA
D. Cells of alar region sharply delimited from the adjacent more distal cells; plants regularly pinnate .....Calliergon giganteum not known from CA

E. Leaves mostly more than 2:1; plants mostly with a reddish wash; most of the cells of the alar region strongly inflated and thin-walled; distal portion of leaves usually with a few nematogons .....Straminergon: S. stramineum
E. Leaves nearly as broad as long, never with a reddish wash; all cells of the alar region with a significant amount of wall-thickening; nematogons not present in leaf .....F

F. Stem leaves apiculate .....Pseudocalliergon: P. turgescens not known from CA
F. Stem leaves with broadly rounded apex .....Pseudocalliergon: P. trifarium not known from CA