FLORA OF LAOS Begoniaceae Begonia quadripetiolata Aver., sp. nov. Vientiane prov., Vang Vieng distr., Oa Hom village, around point 19°06'52.4''N 102°22'35.8''E. Secondary broad-leaved evergreen and semideciduous dry forest with on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 550-650 m a.s.l. Lithophytic herb with stem 10-20 cm tall on shady cliffs. Leaves and petioles uniform green. Locally very common. LA-VN 1510 22 March 2017 Coll.: L.Averyanov, N.T.Hiep, N.S.Khang, C.Q.Ngan, T.Maisak, Khamla Inkhavilay, Hongthong Southyvohanh, Pinmany Sisavath, Chanthala Cheuaysamphanh. Fl. in cult. 20 March 2019. Flowers odorless, white, anther yellow, only male flowers. L. Averyanov, T. Maisak, LA-VN 1510/1. Photos.