The main developmental stages of the pollen wall of Magnolia grandiflora were investigated. Microspore tetrads varied in their morphology. In late microspore tetrads during the callose period, pro-columellae condensed around protrusions of the plasmalemma. As a result of the accumulation of sporopollenin precursors on the protrusions of the plasmalemma, columellae became evident. At a late tetrad stage, the foot layer developed on a white-line-centered lamella. At free microspore stages, the units of the exine thickened, and on further development, white-line-centered lamellae appeared over the inner surface of the foot layer. These lamellae represented a transitory or rudimentary endexine. At the vacuolate stage, a characteristic vesicular-fibrillar layer developed under the rudimentary endexine. The intine developed at the young pollen grains stage and differentiated into two zones with different electron density. The possible function of endoplasmic reticulum and Golgi vesicles in the development of the vesicular-fibrillar layer and the intine is discussed.

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Pollen morphology of Nymphaea lotus L. (Nymphaeaceae) was described by light and scanning electron microscopy. Pollen grains extracted from different types of stamens (including petaloid ones) of N. lotus exhibited a wide range of pollen morphological variation in form, size, aperture, and sculpture. Special emphasis was given to the presence of the primitive monocotyledonoid aperture type referred to as ‘zonisulculate’. The significance of this aperture type in delimiting the phylogeny of the family was discussed. The family Nymphaeaceae was compared with other dicotyledonous (Eupomatiaceae and Monimiaceae) and monocotyledonous families (Araceae, Arecaceae, Liliaceae, Philydraceae, Rapateaceae, and Xanthorrhoeaceae) possessing zonisulculate pollen grains. No direct relationships were considered to exist between Nymphaeaceae and these families when the present pollen morphological study was combined with other morphological characters as revealed by previous taxonomic treatments.

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The pollen morphology of the orders Asparagales and Liliales (Lilianae) mostly in Japan including Nartheciaceae was observed by light microscopy for 106 species of 47 genera in 14 families. Pollen grains are monad and vary from 19.2 (Chionographis japonica) to 196.0 μm (Lilium longiflorum) in the longest axis. The grain shape is usually ellipsoidal to spherical, and rarely obtuse tetrahedral (Dianella), tetrahedral spherical (Chionographis), obtuse triangular prismal (some individuals of Tofieldia japonica), or orange segmental (Allium, Nothoscordum). The pollen class is usually 1-sulcate, and rarely inaperturate (Aspidistra, Smilax, Tupistra), omniaperturate (Heterosmilax, Trillium), 2-sulcate (Tofieldia, Uvularia), 4-porate (Chionographis), 1-trichotomosulcate (Dianella), or 2-trichotomosulcate (some individuals of Tofieldia japonica). The sculpture is usually reticulate or perforate, and rarely gemmate, verrucate, clavate, granulate, or echinate. Sulci usually extend to the grains ends without marginal thickenings. The sulcus of some grains has a granulate membrane or an operculum with a sculpturing pattern similar to that of the exine. Pollen grains of the Asparagales and Liliales were classified into 20 types based on these characteristics, and recent classifications of the Asparagales and Liliales were reevaluated based on these pollen types.

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