RESTRICTED TAXONOMIC VALUE OF LEAF SECTIONS IN CANADIAN NARROW-LEAVED FESTUCA (POACEAE)

Diverse anatomical patterns observed in 18 narrow-leaved Festuca taxa [F. altaica, F. campestris, F. hallii, F. auriculata, F. baffinensis, F. rubra, F. brachyphylla, F. filiformis, F. hyperborea, F. idahoensis, F. occidentalis, F. richardsonii, F. saximontana, F. trachyphylla, F. viridula, F. saximontana var. purpusiana, F. vivipara (incuding subspecies F. v. glabra and F. v. hirsuta)] are illustrated by composite block diagrams formed from a synthesis of at least 10 leaf cross sections from 5 plants chosen across the geographical range of each taxon; the terms used are described; and cross sections are illustrated using semithin leaf sections and block diagrams. Measurements on 7 variables and notes on sclerenchyma patterns from the cross sections are presented in anatomical descriptions for 18 taxa. Results of analyses of variance and deviance show that 5 of the 7 variables have significant differences in mean values that coincide with the taxonomy. However, the range of values observed for each taxon overlapped with that of others so much that measuring these variables for an unknown plant would not always give a reliable identification to species, although it would reduce the possibilities.