Abstract: Although Arabidopsis, particularly A. thaliana (L.) Heynhold, is the model plant of modern molecular biology, its taxonomic position has been disputed. Here we compared seed-coat micromorphology of Arabidopsis and its related genera in Brassicaceae from China by scanning electron microscopy. Furthermore, we sequenced the chloroplast DNA trnL intron and trnL-F spacer to construct phylogenetic relationships among the genera. Genera related to Arabidopsis include Capsella Medic., Camel ina (L.) Crantz, Crucihimalaya Al-Shehbaz et al., Olimarabidopsis Al-Shehbaz et al., Turritis L., Catolobus L. and Erysimum Kitagawa.