Horticulturae 2023, 9, 732. https://doi.org/10.3390/horticulturae9070732 www.mdpi.com/journal/horticulturae Article Micromorphology of Barleria albostellata (Grey Barleria) Flower and Pollen Grains Serisha Gangaram 1, *, Yougasphree Naidoo 1 , Yaser Hassan Dewir 2 , Moganavelli Singh 1 and Katalin Magyar-Tábori 3 1 School of Life Sciences, Westville Campus, University of KwaZulu-Natal, P.O. Box X54001, Durban 4000, South Africa; naidooy1@ukzn.ac.za (Y.N.); singhm1@ukzn.ac.za (M.S.) 2 Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia; ydewir@ksu.edu.sa 3 Research Institute of Nyíregyháza, Institutes for Agricultural Research and Educational Farm (IAREF), University of Debrecen, P.O. Box 12, 4400 Nyíregyháza, Hungary; mtaborik@gmail.com * Correspondence: serishagangaram@yahoo.com Abstract: Barleria albostellata C.B. Clarke (grey barleria, Acanthaceae) is an indigenous shrub to South Africa and has been relatively understudied. This shrub is a valuable medicinal plant with a wide spectrum of antibacterial and anti-inflammatory activities. Detailed studies on the floral and pollen morphology on B. albostellata are rare. This study was conducted to observe the morphology of the flower and pollen grains using stereomicroscopy and scanning electron microscopy (SEM). Morphological observations showed numerous non-glandular trichomes on the bracteoles and bracts of B. albostellata. Three types of trichomes were identified on these structures: I—unicellular, II—multangulate-dendritic branched non-glandular trichomes, and III—capitate glandular tri- chomes. A taxonomical description of the floral structures using stereo and SEM micrographs is provided. SEM micrographs revealed the pollen grains as globose tricolporate with a rough honey- comb exine, and small granules inside the lumina. The diameter of the pollen grains was 77.53 ± 5.63 µm, whereas the aperture of these grains was 14.31 ± 0.59 µm. This study provides insight into the floral biology of B. albostellata, and the results presented here will add to the body of knowledge and encourage further research on this species. Keywords: capitate glandular trichomes microscopy; morphology; non-glandular trichomes; pollen grains; trichomes 1. Introduction Flower receptiveness plays an important role in pollination variability, reproductive success, and plant productivity [1,2]. These active traits include timing of the anther open- ing and pollen appearance, anther and stigma position, and flower receptiveness and morphology [3,4]. Pollination involves the transferal of pollen from the anther to the stigma of the flower [2,5], and the rate of success is highly dependent on pollen viability (the capability of pollen to induce seed set efficiently) [6,7]. Furthermore, the reproductive success of a plant may depend on its ability to atract flower visitors. These visitors that aid in pollination may exert selection on specific floral traits that are attractive to them [7–9]. The genus Barleria has approximately 300 species of shrubs and herbs that are distributed in the subtropical and tropical regions of the world [10–13]. Members of this genus origi- nated from the Far East of Japan, through southern Asia, Arabia, India, Africa, Madagas- car to as far west of Central America and Mexico [12,14]. Several species of Barleria are known for their floral diversity. Additionally, there are specialized structures on their sur- face for the synthesis, storage, and/or secretion of secondary metabolites with the ultimate goal of anti-herbivory tactics and protection against water loss [15,16]. These structures Citation: Gangaram, S.; Naidoo, Y.; Dewir, Y.H.; Singh, M.; Magyar-Tábori, K. Micromorphology of Barleria albostellata (Grey Barleria) Flower and Pollen Grains. Horticulturae 2023, 9, 732. htps://doi.org/10.3390/ horticulturae9070732 Academic Editors: Wajid Zaman and Alessandra Carrubba Received: 17 May 2023 Revised: 14 June 2023 Accepted: 20 June 2023 Published: 21 June 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Atribution (CC BY) license (htps://creativecommons.org/license s/by/4.0/).