Development of hybrid embryos in the cross between F₁<i>C. grandiflorum</i> ‘Zhongshanjingui’ × <i>A. vulgaris</i> ‘Variegata’ (♀) and F₁<i>C. crassum</i> × <i>C. chinense</i> (♂).

<p>(A) Multicelled proembryo and free nuclei of endosperm at 2 days after pollination (DAP). (B) Globular proembryo and free nuclear endosperm at 4 DAP. (C) Early heart-shaped embryo at 6 DAP; note the crimpled integumentary endothelium and reduced number of endosperm nuclei. (D) Torpedo-shaped embryo at 8 DAP. (E) Cotyledon-shaped embryo at 10 DAP; the endosperm is almost eliminated. (F) An unfertilized embryo sac at 4 DAP. (G) Degenerated multicelled proembryo. (H) Degenerated globular proembryo. (I) Degenerated heart-shaped embryo. (J) Degenerated torpedo-shaped embryo. (K) Degenerated cotyledon-shaped embryo. (I) An abnormal cotyledon-shaped embryo; note the bilateral cotyledons elongated laterally rather than along the longitudinal axis. Abbreviations: Efn: endosperm free nucleus; Em: embryo. Scale bars: a–c and g–j: 40 µm; d–f and k–l: 80 µm.