Pollinarium morphology of Vincetoxicum (Apocynaceae: Asclepiadoideae) in Turkey

Abstract

In this study, the pollen morphology of 20 representatives of ten taxa of Vincetoxicum from Turkey was observed under a scanning electron microscope and light microscope. Observations showed that each flower contained five pollinaria, including a pair of pollinia and caudicles attached to a central corpusculum. In the investigated taxa, the shape of the pollinium varied from ovate, elliptical, and obovate, to clavate, pollen cell surfaces exhibited gemmate or rugulate ornamentation, and the shape of the corpuscula was ovate or oblong. Numerical analysis showed that the shape of pollinia and corpuscula, size and surface ornamentation of pollen cells, and size of corpuscula and caudicles are valuable traits in delimiting the examined taxa. A key to Turkish Vincetoxicum based on pollinarium morphology is presented.

Palynological investigation of lactiferous flora (Apocynaceae) of District Rawalpindi, Pakistan, using light and scanning electron microscopy

“…Pollen aperture type, their arrangements, number, and exine ornamentation are very diagnostic features regarding the taxonomic‐phylogenetic point of view (Aftab & Perveen, ). Sometimes pollen shows regularity and distinctiveness in their features of a taxon but within natural groups pollen may remarkably vary in size, exine appearance, and aperture type (Güven, Makbul, Coskuncelebi, & Pinar, ). Pollen grains features were considered as a convenient mean for the corresponding morphological studies that leads to the assessment, phylogeny, and plant taxonomic consequences rather than some other morphological features.…”

Contribution to chromosome numbers and phylogeny of Turkish Vincetoxicum Wolf (Apocynaceae, Asclepiadoideae)

“…According to our phylogenetic analyses, V. canescens and V. tmoleum also clustered in the same group (including V. creticum) corresponding to the 'Eastern Mediterranean clade' in Liede-Schumann et al (2016). It was reported that these two species had many morphological and palynological characteristics in common, such as densely hairy corolla and deeply parted corona segments (Güven 2017), an ovate pollinium and corpusculum shape, and a rugulate pollen surface (Güven et al 2015). The similarity in floral morphology between V. canescens and V. tmoleum was also reported by Browicz (1975).…”

“…However, these taxa have some floral features in common, such as hairy corolla and cup-shaped five-parted corona (Pobedimova 1952;Güven 2017). Furthermore, V. funebre and V. scandens have similar palynological (obovate pollinium and oblong corpusculum) characteristics (Güven et al 2015) and the same chromosome number of 2n=2x=22.…”

“…hirundinaria has a white corolla and crisped hairy stems that occasionally twine near the apex (Browicz 1975). Güven et al (2015) noted that the pollinia surface of V. speciosum exhibited gemmate ornamentation, in contrast to the rugulate surface in V. hirundinaria subsp. hirundinaria.…”

“…grows in various habitats ranging from dry river valleys, open rocky slopes, steppes and mountain slopes, to shrubland and Quercus-dominated forests in Turkey (Browicz 1978). Until now, a few anatomical and seed micro-morphological (Ilçim et al 2010), ethnobotanical (Doğan 2008;Altundağ & Öztürk 2011), pharmaceutical (Özay 2013), and palynological (Güven et al 2015) studies have been reported on Turkish Vincetoxicum s. str. taxa.…”