Suk-Pyo Hong

Pollen Morphology of Parapteropyrum and Some Putatively Related Genera (Polygonaceae – Atraphaxideae)

Abstract The pollen of the monotypic genus Parapteropyrum and 10 species from three putatively related genera (Pteropyrum, Atraphaxis and Calligonum) in the tribe Atraphaxideae was examined by light and scanming electron microscopy. Three pollen types, differing in exine sculpturing can be recognized: (1) microreticulate in Parapteropyrum and Pteropyrum (2) striato-reticulate to striate in Atraphaxis (3) punctate with perforations in most Calligonum species. Pollen grains of Parapteropyrum and Pteropyrum are morphologically very similar and the only difference between them is in size. Pollen morphology therefore does not support a generic distinction for Parapteropyrum. The distinctive surface pattern of Atraphaxis pollen grains suggests no very close relationship with Parapteropyrum and Pteropyrum nor with those species of Calligonum investigated. From palynological data it seems probable that Atraphaxis evolved independently into a specialized group from the common ancestral stock of the tribe Atraphaxi...

Parallel evolution of aperture numbers and arrangement in the genera koenigia, persicaria and aconogonon (polygonaceae)

Abstract Pollen of 30 species representing the genera Koenigia, Persicaria and Aconogonon was examined by light microscopy and scanning electron microscopy. Pollen descriptions are given for each genus. Earlier palynological investigations of each genus are listed. Each of the genera is characterized by a particular surface structure (spinulose in Koenigia, semitectate reticulate in Persicaria, and with microspinules in Aconogonon), but the number and arrangement of the apertures varies considerably, showing interesting parallels in the three genera. All three genera follow the pollen evolutionary model called ‘successiformy’. A few evolutionary and phytogeographically interesting intermediates between these three genera are discussed.

The dimorphic heterostyly inAconogonon campanulatum (Polygonaceae)

Heterostyly is clearly confirmed inAconogonon campanulatum. This distylous species is dimorphic for tepals, styles, stigma surface, stamens, pollen grain size, and pollen sexine ornamentation. The floral shape is campanulate and thrum flowers are slightly larger than pin flowers. Small solitary bees were observed as flower visitors and probably effected pollination. The possible evolution of dioecy via heterostyly within the genusAconogonon is discussed.

Reconsideration of the generic status ofRubrivena (Polygonaceae, Persicarieae)

Morphological and anatomical characters (including pollen morphology) of the genusRubrivena are described. The phylogenetic relationships ofRubrivena, the putatively related genusKoenigia and the four sections of the genusPersicaria are analyzed by the application of cladistic methods.Persicaria s. str. turns out to be paraphyletic; however, inclusion ofRubrivena produces a clade which is marked by five synapomorphies (e.g., long styles, semitectate reticulate pollen grains and some seed characters). In order to eliminate the paraphyly ofPersicaria as well as to avoid nomenclatural changes of all taxa of sect.Cephalophilon, Rubrivena is included in the genusPersicaria. Sect.Rubrivena differs from the other sections in pollen morphology [granulated muri and 6 (–7)-zonocolpate aperture system] and inflorescence type (well-branched panicles). In addition, heterostyly is confirmed inPersicaria wallichii, and is reported here also forP. pinetorum. Keys and descriptions are provided for all taxa and a distribution map is given. Two species are illustrated by line drawings. One new variety,Persicaria wallichii var.tomentosa, is described. Five lectotypes are selected.

A Pollenmorphological Re‐evaluation of Harpagocarpus and Eskemukerjea (Polygonaceae)

Abstract The pollen morphology of the monotypic genera Harpagocarpus (tropical Africa) and Eskemukerjea (Nepal) is shown to agree with that of Fagopyrum. The amalgamation of these two genera with Fagopyrum is proposed and the new combination F. snowdenii (Hutch. & Dandy) S.‐P. Hong is made.

Pollen morphology of the tribe Pterostegieae (Polygonaceae: Eriogonoideae)

Pollen of two North American monotypic genera (Pterostegia and Harfordia) in the tribe Pterostegieae (including three varieties of Harfordia ca. 22 specimens in total) was examined with light microscope and scanning electron microscope. Detailed descriptions of the inner surface of the tectum and endoapertures were investigated using freezing microtome sections in SEM. The pollen of Pterostegieae can be characterized as being usually 3‐colporate, lolongate or almost circular (more common in Harfordia) and having endoapertures with a subtectate‐microreticulate or ruglo‐/striato‐perforate exine sculpturing. The pollen grains of Pterostegia and Harfordia are very much alike and are therefore, not easily separable, although there are some slight variations (especially in pollen size and sexine patterns, etc.). The infratectum of pollen in Harfordia is covered with comparatively few and less dense granules than that of Pterostegia and these characters are reported for Pterostegia drymarioides for the first tim...