Taxonomic implications of pollen exine morphology in infrageneric classification of Scutellaria (Lamiaceae)

Abstract

and M. Hasani-Nejad, Research Inst. of Forests and Rangelands, PO Box 13185-116, Tehran, Iran. Scutellaria L. in Lamiaceae subfamily Scutellarioideae is a subcosmopolitan genus with about 360 species. According to the latest subgeneric classifi cation, two subgenera are recognized: S. subgen. Scutellaria and S. subgen. Apeltanthus . We studied pollen grains from 29 species of Scutellaria belonging to both subgenera and from both the Old and the New World to evaluate their taxonomic importance for the infrageneric classifi cation of the genus. Pollen grains were acetolysed and studied by scanning electron microscope (SEM) and light microscope (LM). All examined pollen grains are isopolar, tricolpate, suboblate, oblate spheroidal, prolate spheroidal to subprolate. Th e exine is mainly bireticulate perforate, but with variations in lumina shape and size as well as perforation size and uniformity. Based on the exine sculpturing, two subtypes are recognized within the bireticulate pollen type. In subtype I the primary reticulum of the exine consists of angular muri; the lumen has an irregular polygonal shape and the perforations of the secondary reticulum are more or less uniform and of the same size. Th is pollen subtype was observed in species of subgenus Scutellaria , sectt. Scutellaria p.p., Anaspis , Perilomia and Salazaria . In subtype II the primary reticulum of the exine consists of a more or less curved murus; the lumen is rounded or obtusely angular and the secondary reticulum consists of one or more large central perforations surrounded by some smaller ones. Th is pollen subtype was observed in species of subgenus Scutellaria sectt. Scutellaria p.p., Salviifoliae and in all members of subgenus Apeltanthus . Th e results of this study reveal that the exine ornamentation is a diagnostic character useful for the infrageneric classifi cation of Scutellaria .

Pollen morphology of certain species of the family Lamiaceae in Saudi Arabia

“…17) Lavandula dentata and Lavandula pubescens (Table 2, Figs. 3 and 8, examined by LM) The results of the first three species agree with that mentioned by Kose et al, 2011, Dinç et al, 2009 and Jamzad and Hasani-Nejad (2013). The surface ornamentation of the last two species is mentioned as reticulate under SEM (Evert and Eichhor, 2013) which also confirmed with our findings in this tudy.…”

“…Kose et al (2011) reported that the granulate or reticulate type of exine ornamentation in Ajuga species may be is useful in segregating the species within the genus. Hasani-Nejad et al (2011) and Jamzad and Hasani-Nejad (2013) showed that the exine ornamentation could be used as a taxonomic feature below generic level classification of Scutellaria. Osman (2012) in his study of Ballota species in Egypt mentioned that pollen characters were very useful in the separation of the species.…”

The pollen morphological diversity of Ziziphora clinopodioides (Lamiaceae)

“…Ziziphora clinopodioides has a large geographical distribution and represents high morphological diversity in Iran and adjacent countries. Our investigations have revealed that the pollen grain morphology can be useful in clarifying the infra-specific classification (Jamzad and Hasani-Nejad 2014, Keshavarzi et al 2008, Selvi et al 2013, Tabaripour et al 2018, such as the ornamentation of the pollen grains have valuable morphological characteristics to solve taxonomic problems of some subspecies in Ajuga. The sculpture of A. chamaepitys subsp.…”

Positive Selection and Functional Divergence of R2R3-MYB Paralogous Genes Expressed in Inflorescence Buds of Scutellaria Species (Labiatae)

“…Species of Taiwanese skullcaps, which have been suggested to be rapidly evolving [ 9 ], are morphologically varied in petal colors and vegetation forms ( Table 1 ). High interspecific variation in the pollen size and exine, which are major taxonomic characters in Scutellaria [ 44 ], and which are regulated by MYB16 , could be related to the pollinator shift between different Scutellaria species [ 43 ]. The positive sites 134Y in MYB11 and 196C in MYB16 , both of which had high posterior probabilities, are located within the DNA-binding domain.…”