1 RESEARCH ARTICLE Seed micromorphology and its taxonomic evidence in subfamily Alsinoideae (Caryophyllaceae) Fazal Ullah 1,2,3 | Alessio Papini 4 | Syed Nasar Shah 1 | Wajid Zaman 3,5 | Aamir Sohail 6 | Majid Iqbal 1 1 Department of Plant sciences, Quaid-i-Azam University, Islamabad, Pakistan 2 CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chengdu, Sichuan, China 3 University of Chinese Academy of Sciences, Beijing, China 4 Department of Biology, University of Florence, Florence, Italy 5 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Beijing, China 6 Department of Botany, University of Peshawar, Peshawar, Pakistan Correspondence Fazal Ullah, Department of Plant sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan. Email: fazalbotanist@gmail.com OR Alessio Papini, Department of Biology University of Florence, Italy. Email: alessio.papini@unifi.it Funding information University of Peshawar Review Editor: George Perry Abstract Seed micromorphology of 13 species, belonging to four genera of subfamily Alsinoideae (Caryophyllaceae) were investigated with scanning electron microscopy (SEM), in order to assess their diagnostic significance at generic level and provide additional evidence on species delimita- tion, as well as correct identification and phylogenetic position. Genera and species of subfamily Alsinoideae exhibit great variation in ultrastructure and a high diversity of novel micromorphologi- cal characters were observed. Variation in seed shape, color, hilum, anticlinal wall, epidermal cell, cell surface, margins, and quantitative characters as length and width were studied in detail, com- pared, illustrated, and their taxonomic significant were discussed. Seed shapes of the species were classified as reniform, round, angular, subcircular, subreniform, and elliptical pyriform, with sub- central, central, basal, and nearly basal hilum. Wavy, irregular, tetragonal, and elongated epidermal cells structure has been observed as an exomorphological character. The present findings show that the micromorphology of subfamily Alsinoideae provides taxonomic information and is helpful to distinguish different species. The results also explained that SEM morphology of seeds provide important data about affinity among taxa and give potential characters in delimitation of members of subfamily Alsinoideae at generic and species level. A principal component analysis allowed to highlight the most outsiders among seed micromorphology with a possible explanation. Taxo- nomic keys were developed based on micromorphological characters to delimit the species and useful for their quick identification within subfamily Alsinoideae. KEYWORDS Alsinoideae, hilum, seed morphology, seed surface, SEM 1 | INTRODUCTION Caryophyllaceae is one of the largest dicot family consisting of three subfamilies, that is, Alsinoideae, Caryophylloideae, and Paronychioideae and 11 tribes (Bittrich, 1993), with 88 genera and 2,200 species (Harbaugh et al., 2010). In Flora of Pakistan the family is represented by 110 species and 26 genera distributed throughout the country (Perveen & Qaiser, 2006; Ullah, Zafar, Ahmad, Dilbar, et al., 2018). The family is primarily distributed in the Holarctic but with rich diversity in Irano-turanian and Mediterranean regions (Hernández-Ledesma et al., 2015), most of the species grow in relatively moist habitats and temper- ate forest of the world (Vandelook, Van de Moer, & Van Assche, 2008). Members of the family as Stellaria media (L.) Vill. also grow as important weeds among several crops (Ullah, Ullah, & Sohail, 2016). The dominant features of the subfamily Alsinoideae are the presence of nectar glands on the base of abaxial side of the episepalous stamens and they can be distinguished from Caryophylloideae by tubular calyx and clawed petals (Bittrich, 1993; Harbaugh et al., 2010; Ullah, Zafar, Ahmad, Dilbar, et al., 2018; Ullah, Zafar, Amhad, Shah, et al., 2018). According to the taxonomic classification by McNeill (1980) in subfamily Alsinoideae, Cerastium L., and the Stellaria-Cerastium com- plex are included, together with Myosoton Moench, Moenchia Ehrh., Holosteum L., and Pseudostellaria Pax., as members of tribe Alsineae Lam & Dc. Genus Cerastium is traditionally divided into two Received: 19 September 2018 Accepted: 9 October 2018 DOI: 10.1002/jemt.23167 Microsc Res Tech. 2018;1–10. wileyonlinelibrary.com/journal/jemt © 2018 Wiley Periodicals, Inc. 1