Characteristics and Evolution of Leaf Epidermis in the Genus Amana Honda (Liliaceae)

Abstract

Amana, commonly known as ‘East Asian tulips’, has recently been found to harbor cryptic diversity due to recent field work and systematic investigations. In this study, we included 64 populations from all 12 Amana species and performed microscopic observations of their epidermal morphology. The leaf epidermis stomatal distribution of Amana can be characterized into three types: dense stomata (>10/per view or 263/mm2), sparse stomata (<10/per view or 263/mm2), and stomata absent. The epidermal cells of Amana can be characterized into four types: rectangular, long rectangular, nearly rectangular, and rhombic. The anticlinal wall morphology of the epidermal cells can be characterized into three types: linear, wavy, and nearly linear with mixed shallow waves. All the results were helpful for classification of Amana species. According to the reconstruction of ancestral characters analyses, the common ancestor of Amana is most likely to have leaves with dense stomata on both sides, and epidermal cells that have linear vertical walls.