Some observations on the Carex muricata group with especial reference to the identification and definition of C. divulsa subsp. leersii (Cyperaceae)

Abstract A morphological study of Carex divulsa subsp. leersii is described. This work was prompted by recent finds of the taxon away from its presumed characteristic calcareous substrates, and by the fact that many plants had measurements outside the ranges given in standard descriptions. The study confirmed this to be so for inflorescence length, proximal inter-spike distance and especially for utricle length. Large values for the first two of these characters may have caused confusion in the past with subsp. divulsa and of the last with C. spicata, which also shares the broad leaves and robust, tufted habit of subsp. leersii. The importance of using only plants with mature fruits for identification is stressed, as immature fruits of subsp. leersii are paler and can be up to 0.5 mm shorter than the darker mature ones. Misidentification of subsp. leersii as other taxa in the C. muricata group has led to it being under-recorded, and adoption of the European concept of the taxon is recommended in order to remedy this.