Fig.1

Average temperature of the environment H. hybridum bulbs placed in during the experiment in each month

Fig.2

Schematic diagram of the inflorescence structure and position in H. hybridum ‘Merry Christmas’A-B.Inflorescence morphology and internal structure diagram during bud stage；C-D.Schematic diagram of inflorescence position in bulb during flowering period（C.Inflorescence in bloom；D.Longitudinal section of bulb）；PH.Phyllary；BR.Bracteole；f1-f4.The first to the fourth flower bud from large to small in the inflorescence；F1.The first inflorescence in bloom in the current year；F2-F4.Taking F1 as the first，the second to the fourth inflorescence from the outer layer to the inner layer of the bulb；WF.Withered inflorescences in the previous year

Fig.3

Growth of inflorescences in bulbs each monthF1-F6.The first to sixth inflorescence in bulb，indicated by purple，red，black，pink，green，blue dots respectively；Black arrows indicate dried inflorescences that failed to open

Fig.4

Morphological differentiation of the flower organs in H. hybridum ‘Merry Christmas’A，C，E，G，I，K.Paraffin longitudinal section of flower buds with lengths of 0.02，0.05，0.1，0.2，0.3，0.4 cm；B，D，F，H，J，L.Anatomy observation of flower buds with lengths of 0.02，0.05，0.1，0.2，0.3，0.4 cm；A-B.Flower primordium differentiation stage；C-D.Outer perianth differentiation stage；E-F.Inner perianth differentiation stage；G-H.Stamen differentiation stage；I-J.Carpel differentiation stage；K-L.Ventricle differentiation stage；FP.Flower primordium；OPP.Outer perianth primordium；IPP.Inner perianth primordium；SP.Stamen primordium；CP.Carpel primordium；VE.Ventricle

Fig.5

Microsporogenesis and male gametogenesis development in H. hybridum ‘Merry Christmas’A.Transection of the tender flower bud； B. Outer layer of secondary wall cells develop into endothecium and middle layer；C.Structure of pollen wall；D.Meiotic fine line stage；E.Tetrad stage；F.Mononuclear pollen grain stage；G-H.Mononuclear marginal stage；I-J.2-celled pollen grain stage；K-L.Pollen mature stage（black arrow shows the mature pollen grains）；en.Endothecium；ep.Epidermis；gc.Germ cell；il.Inner layer of secondary wall cell；m.Middle layer；mm.Microspore mother cell；mp.Mononuclear pollen grains；ol.Outer layer of secondary wall cell；sc.Sporogenous cell；ta.Tapetum；vc.Vegetative cell

Fig.6

Megasporogenesis and female gametogenesis in H. hybridum ‘Merry Christmas’A.Transection of the ovary of the tender flower bud；B.Archesporium cell stage；C.Megaspore mother cell stage；D.First meiosis stage（white arrow shows the degenerate cell in the micropylar end，black arrow shows the functional cell in the chalazal end）；E.Dispore embryo sac stage；F.Four nuclear embryo sac stage；G.Eight nuclear embryo sac stage；H-L.Mature embryo sac stage；an.Antipodal cell；ar.Archesporium cell；eg.Egg cell；me.Megaspore mother cell；op.Ovule primordium；pn.Polar nuclei；sy.Synergid；nc.Nucellus cell

Table 1

Comparison of embryological characters among Hippeastrum，Narcissus，Zephyranthes and Lycoris