Pollination of Couroupita guianensis.

• Title

  Pollination of Couroupita guianensis.

• Authors

  Scott Alan Mori

• Description

  Thompson (1927) was the first to suggest that pollen from the hood of Couroupita guianensis does not germinate on the stigma, but it was Jacques (1965) who first observed that the ring and hood pollen are different. This observation has been confirmed by Mori et al. (1980), Ormond et al. (1981), and Yarsick et al. (1986). These authors have demonstrated that the pollen of the staminal ring is found in monads and has a smooth exine while that of the hood is in tetrads and has a rougher exine. Ormond et al. (1981) add that the ring pollen is covered with droplets of a lipid substance whereas that of the hood is dry. Examination of the stigma shows that monad pollen dominates the surface while tetrad pollen is rarely found there. The ring pollen shows a high degree of both in vitro and in vivo germination whereas not a single pollen grain from the hood anthers germinates (Mori et al., 1980; Ormond et al., 1981).  In conclusion, it has been clearly demonstrated that there are two types of pollen in the flower of Couroupita guianensis and that the most likely pollinators are species of large bees, such as Bombus and Xylocopa, which are rewarded for their efforts with non-germinating pollen that they collect from the hood.