Cypselar Anatomy of Two Species of the Tribe Anthemideae, Family Asteraceae

Abstract

The family Compositae is the largest and most successful among the angiosperms because of its adaptability in wide variety of ecological habitats and the family owes its biological and commercial success to certain morphological, anatomical and physiological characters in their flowers and fruits. The tribe Anthemideae is one of the most primitive tribe of the Asteraceae. The anatomical features of the species have been investigated to establish their potential usefulness in taxonomy. This study is important for showing how the family owes its biological and commercial success to certain morphological, anatomical and physiological characters in their flowers and fruits. The significant anatomical features of cypselas are cypselar shape in T.S., cypselar cuticle, ribs or elevations no., size of the ribs, thickness of cypselar wall (in μm) at ribs and furrow, pericarp thickness (in μm) at ribs and furrow, tissue differentiation of epicarp, epicarpic cell shape, epicarpic cell wall thickness, orientation of epicarpic cell, tissue differentiation of mesocarp, mesocarpic parenchymatous cell, mesocarpic sclerotic braces, mesocarpic vascular bundle, mesocarpic resin cavity, mesocarpic cavity, presence of endocarp, testa thickness (in μm), testal attachment with pericarp, tissue differentiation of testa and layers, cell content of testa, testal cell shape, thick walled cells of testa, crystals and their distribution, testal palisade cells, orientation of testal cells, endosperm in mature cypsela, non–cellular pellicle, nature of mature embryo, resin ducts/secretory ducts in each cotyledon and relative size of the secretory ducts etc., have been examined. These characters of cypselas serve as reliable taxonomic marker in systematic study. Based on these above features, an artificial key is prepared for easy identification.