Abstract: The Trillium tschonoskii Maxim. is distributed in Mt. Emei of Sichuan. The ovule is of anatropus and crassinucellate type. When mature, it has two layers of integuments, of which,the outer one consists of two-three layers of cells, whilc the inner of two. The micropyle is formed by both integuments.A unicellular archesporium is derived from the hypodermal cell at the tip of the young nucellus, which divides to form a parietal cell and a sporgenous cell. The magaspore mather cell is formed from the development of the sporogenous cell and gives rise to a bisporie embryo sac. The first meiotic division is acconpanied by wall formation, so that a dyad is formed.Usually the chalazal dyad cell is bigger than the micropolar one and is fill by many starch grains. Only one of the dyad cells undergoes the second meiotic division whereas the other one degenerates. In the functional dyad cell wall formation does not occur of the second meiotic division and both magaspore nuclei contribute to the formation of embryo sac, which is derived from the chalazal dyad cell. The mature embryo sac is not magasporogenesis and megagametophyte development is something deviated from the normal type of the Allium. Synergids have filiform apparatus at its upper end.The mature male gametophyte pollen grain is two cells. The wall of undifferentiated anther showed the existence of amoeboid topetum. The endosperm is Holobial type.