Abstract

• The grass family Poaceae and Sedges family Cyperaceae are belonging to order Poales. (APG IV, 2016) and very similar in features. But these two families are so differing from each other by individual morphological characters. Grass belongs to family Poaceae (Gramineae) and the largest family in monocotyledonous gramineous flowering plants. The name of family Poaceae is derived from types genus Poa L. Family Cyperaceae is the third largest family of monocotyledonous gramineous flowering plants and type genus is Cyperus. Grass taxonomy is very different and difficult from other flowering plants. Grass floret is spikelet and individual spikelet possess each substances bract (glumes, lodicule) and various modified inflorescences types and underground organs. These reproductive and vegetative morphological characters of Poaceae is more advance evolution trends features than Cyperaceae. This feature agreed in evolutionary trends of morphological characters and APG IV 2016 system. Family Cyperaceae is one spiculose flower and these organized into spikelet (glumes, perianth). Spikelet further arranged into higher order spicate, paniculate or umbellate inflorescence (anthela). Flowers of both families may be perfect or imperfect, usually monoecious. In this research highlights the quite different characters of very similar morphological unit features of grass and sedges and then verify primitive and advance comparison characters between Poaceae and Cyperaceae with systematics science record in region, Myanmar.