RESEARCH ARTICLE Taxonomic importance of spore morphology in Thelypteridaceae from Northern Pakistan Syed N. Shah 1,2 | Mushtaq Ahmad 1 | Muhammad Zafar 1 | Fazal Ullah 1,3,4 | Wajid Zaman 1,4,5 | Khafsa Malik 1 | Neelam Rashid 1 | Saba Gul 1 1 Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan 2 Science Laboratory, Government High School, Dherai Puran, Shangla, Pakistan 3 CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China 4 University of Chinese Academy of Sciences, Beijing, China 5 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China Correspondence Syed N. Shah, Department of Plant Sciences, Quaid-i-Azam University Islamabad, Pakistan. Email: nasarshah67@gmail.com Review Editor: Paul Verkade Abstract Spore morphology of Thelypteridaceae species growing in Malakand Division, Northern Pakistan, was studied using both light microscopy and scanning electron microscopy. The taxa are Christella dentata and Glaphyropteridopsis erubescens in the subfamily Thelypteridoideae, and Phegopteris connectilis, Pseudophegopteris pyrrhorhachis, and Pseudophegopteris levingei in the subfamily Phegopteridoideae. The studied species exhibit differences in spore size, exospore thickness, color, and ornamentation. Spores of the studied species are monolete and medium-sized, and shape is ellipsoidal in both polar and equatorial views. The average measurement of the polar diameter ranges from 27 μm to 31 μm, whereas in the equatorial direction it varied from 20 μm to 40 μm. The exospore thickness ranges from 1.2 μm to 2.4 μm. Reticulate, laevigate with microgranules, cristate, and coarsely echinate surface ornamentation are observed among the species. Multivariate analysis including unweighted pair group method with arithmetic mean and principal component analysis was used for the grouping and discrimination of species and genera. KEYWORDS multivariate analysis, Palynotaxonomy, spore morphology, surface ornamentation 1 | INTRODUCTION Thelypteridaceae is a fern family estimated to contain 1,034 species distributed in 30 genera, which have wide geographical distributions, although species are more diverse in tropical regions (PPG1, 2016). The members of this family are terrestrial with branched and unbranched stems; bearing scales at the apex, these are entire, usually pubescent along margins; vascular system a radially symmetrical dictyostele; peti- oles nonarticulate; indusia present or absent, if present then reinform; and spores 64 per sporangium, nearly always bilateral with a monolete scar (Holttum, 1959; Smith, 1990). The family is considered monophy- letic and comprises two primary lineages, one phegopteriod and the other thelypteroid, classified into the subfamilies Phegopteridoideae and Thelypteridoideae (PPG 1, 2016). The phegopteriod lineage includes those species that are the most dissected, lack adaxial grooves on the frond axes, and are, in general, morphologically the most distinctive branch in the family. Within the thelypteriod line- age, three predominantly north temperate subgroups, including Thelypteris, form a free vein clade that is in turn sister to the rest of the family (Smith & Cranfill, 2002). The subfamily Phegopteridoideae is monophyletic and estimated to contain three genera and 34 species globally (Almeida et al., 2016; He & Zhang, 2012; Smith & Cranfill, 2002). The subfamily Thelypteridoideae, which is also regarded as monophyletic by Smith and Cranfill (2002), He and Zhang (2012), and Almeida et al. (2016), is estimated to contain 27 genera and 1,000 spe- cies. The subfamily Phegopteridoideae includes three genera, namely Macrothelypteris, Phegopteris, and Pseudophegopteris (Almeida et al., 2016; He & Zhang, 2012; PPG, 2016; Smith & Cranfill, 2002). In Pakistan, Thelypteridaceae is represented by eight species distrib- uted in seven different genera: Ampelopteris prolifera, Christella dentata, Received: 22 January 2019 Revised: 4 April 2019 Accepted: 24 April 2019 DOI: 10.1002/jemt.23283 Microsc Res Tech. 2019;1–8. wileyonlinelibrary.com/journal/jemt © 2019 Wiley Periodicals, Inc. 1