To determine the reproductive characteristics of the dandelion Taraxacum antungense, we examined the mating system, pollen viability, pollen tube germination, embryo sac development, and ploidy. The apomictic ratio was relatively high and the pollen viability 20.6%. Pollen could not germinate by self-pollination, but by outcrossing, it could germinate with the slowly growing pollen tube. The pollen tube completed growth before reaching the ovary and then degenerated. At dyad phase, the micropylar megaspore degenerated and the chalazal megaspore formed a functional megaspore. The development pattern of the embryo sac is polygonum type. The egg cell and central cells convert to embryo and endosperm, without fertilization, respectively. Before inflorescence, the globular embryo forms. Chromosome counting confirmed T. antungense as triploid. Flow cytometry revealed that T. antungense is obligate apomictic, and the development of endosperm is autonomous.