FIG. 20 in A study of the morphology and distribution of four Achnanthidium Kütz. species (Bacillariophyta), implications for ecological status assessment, and description of two new European species

FIG. 20. — Principal component analysis of elliptic Fourier shape harmonics for specimens of Achnanthidium sieminskae Witkowski, Kulikowskiy & Riaux-Gob. from different geographic regions (Europe, Wales, Scotland and England). Specimens of Achnanthidium caledonicum (Lange-Bert.) Lange-Bert. are used as the outgroup. The biplot presents the first two axes with a total explained variance of 92.4 %.