Fig. 1.

Key stages of pistillate (upper panel) and staminate (lower panel) flower development in oil palm. Developmental stages (indicated at bottom left of each photo) were assigned on the basis of the differentiation of the floral whorls. Stage 1 corresponds to a floral meristem. Stage 2 corresponds to the initiation of perianth organs. Stage 3 corresponds to the development of perianth organs and the initiation of reproductive organs. Stage 4 corresponds to the development of reproductive organs and stage 5 to a mature flower. Photographs are of either PAS/NBR-stained transverse and longitudinal sections or scanning electron micrographs (right-hand photographs, upper and lower panels). Abbreviations: asf1/asf2, accompanying staminate flowers 1 and 2; B, bracteole; BI/BII, bracteoles I and II; c, carpel; ff, pistillate flower; fm, floral triad meristem; Fb, floral triad bract; o, ovule; p, petal; s, sepal; sta, staminodes; c, carpel; m, megaspore mother cell; ps, pollen sac; sta, staminodes; te, tetrads; tg, integuments.