1. Leaf cells at sheathing base hyaline, abruptly differentiated from the cells above; stem leaves deciduous.... 2
1. Leaf cells at sheathing base not hyaline, usually orange or brownish, gradually differentiated from the cells above; stem leaves persistent................................................................................................................................... 3
2. Costae ending below leaf apex, papillose at back; median leaf cells ca. 9–14 µm wide..................................
............................................................................................................................. 3a. T. norvegica var. norvegica
3. Basal leaf cells orange, pluripapillose; plants dioicous
................................................................. 1. T. austriaca
3. Basal leaf cells somewhat transparent, yellowish or brownish, inconspicuously papillose; plants antoicous 4
4. Upper leaf cells rounded-hexagonal; cells at sheathing base papillose; costae papillose at back...................
4. Upper leaf cells quadrate-hexagonal or rectangular; cells at sheathing base smooth; costae smooth at back
.....................................................................................................2b. T. megapolitana var. bavarica