The staminate flower ofPtychosperma mooreanumandP. gracilehas three imbricate sepals, three valvate petals, an androecium of 9–13 or 27–32 stamens, and a lageniform pistillode. Pistillate flowers have three imbricate sepals, but the three petals are also imbricate, and the three (‐seven) staminodes are irregular and sometimes basally fused. The ovoid pseudomonomerous pistil has a single locule with a pendulous ovule and three small distal stigmatic lobes. All floral organs are initiated by periclinal divisions in the second tunica layer of the floral apex, with divisions in the outer layer of the cortex also apparent in the initiation of stamens and staminodes. Primordia of floral organs differ in shape but can be related to those of other palm flowers. Sepals are initiated and develop successively, and during floral organogenesis are horizontally oriented covering other organs. Petals are also initiated successively, but rapidly attain equal size. Petals of staminate and pistillate flowers are initially similar, but subsequent prolonged activity of marginal meristems results in widely imbricate petals in pistillate flowers. The polyandric androecia are clearly trimerous. As stamen initiation commences, the apex is divided into sectors or primary primordia consisting of a narrow ridge opposite each sepal and a large triangular bulge opposite each petal. Stamens arise as secondary primordia in alternating antesepalous and antepetalous cycles. Variation in number of stamens is due primarily to variation in the number of primordia that arise in the wider lower antepetalous loci. The primordium of the pistillode is girdling but becomes trilobed later. The gynoecium is initiated as three unequal crescentic carpel primordia that are united by zonal growth early in development. A procambial strand develops acropetally into each floral organ, and additional strands are formed as each organ increases in size. Floral organs are histologically specialized. The appearance of tannins, raphides, and silica and the maturation of sclerenchyma are basipetal within each floral organ.