‘Tonda gentile delle Langhe’ hazelnut bloomed from 22 Dec. to 19 Jan. Fertilization occurred about 5 months later, in the last 10 days of May. In the first days of June, the embryo was globular whereas the free nuclear endosperm had started to become cellular. Around the middle of June the embryo was heart-shaped and the endosperm was entirely cellular. In the following 2 weeks, the endosperm became vacuolated and then disintegrated. Cotyledons formed (torpedo stage) and grew quickly, filling the ovule by the end of June. The seed had its final shape and dimension by 20 July, but the embryonal axis continued elongating until nut maturity, 15 to 30 Aug. Mature embryos contained six to eight leaf primordia, the apical meristem, and the radicle.