NORDIC JOURNAL OF BOTANY Research article On the taxonomic identity of Capillipedium mistryi A. P. Tiwari & Landge (Poaceae: Andropogoneae) and synonymisation of C. yashwantraoi Tarbej & Potdar as its new heterotypic synonym Shahid Nawaz Landge ✉1, Arjun Prasad Tiwari 2 and Rajendra D. Shinde3 1 The Blatter Herbarium (BLAT), St. Xavier College, Mumbai, India Regional Museum of Natural History, Mysore, India 3 St. Xavier’s College (Autonomous), Mumbai, India 2 Correspondence: Shahid Nawaz Landge (schahiedknavaze@gmail.com) Nordic Journal of Botany 2023: e03986 doi: 10.1111/njb.03986 Subject Editor: Torbjörn Tyler Editor-in-Chief: Torbjörn Tyler Accepted 7 April 2023 Published 17 May 2023 The present study assesses the taxonomic identity of the two recently described Indian species of Capillipedium i.e. C. mistryi and C. yashwantraoi from the state of Madhya Pradesh, central India. Both of the species share important features, such as multispiculated racemes, solid pedicel and rhachis internode (non-translucent). As these features are unique in Capillipedium they are of peculiar interest. Having multi-spiculated spiciform racemes, these taxa can be best compared with a similar, non-Indian congener, C. spicigerum which is distributed from China to Australia. Based on comparative morphological study using their protologues and the type specimens, it is concluded that C. yashwantraoi is conspecific with C. mistryi. Therefore, the former is treated as a new heterotypic synonym under the latter following the principle of priority. Keywords: Andropogoninae, Gramineae, India, Madhya Pradesh, synonym nova, taxonomy Introduction Capillipedium Stapf (1917) is represented by 19 species distributed in tropical Africa, tropical and subtropical Asia and Australia (Clayton et al. 2019, Tiwari and Landge 2021, POWO 2023). According to Plants of the World Online (2023), no infraspecific taxa are recognised in the genus. In India, the genus is represented by nine species of which seven appears to be endemic (Tiwari and Landge 2021). Conventionally, Capillipedium is distinguished from closely allied genera by the short racemes that are usually consisting of 1–5 (–8) sessile spikelets, capillary branches of the panicle, and rhachis internodes and pedicels with a distinct median translucent groove (Bor 1960, Simon and Alfonso 2012, Kellogg 2015). One of the closely allied genera to share the latter feature is Bothriochloa, a synopsis of which was recently published from India (Landge and Shinde 2021, 2022a, b). Capillipedium mistryi Tiwari and Landge (2021), a recently described new species is quite unusual in the genus with its solid rhachis internode and pedicel, and www.nordicjbotany.org © 2023 Nordic Society Oikos. Published by John Wiley & Sons Ltd Page 1 of 4 multi-spiculated racemes which may comprise up to 26 fertile sessile spikelets. These characters are newly added to the circumscription of Capillipedium (Tiwari and Landge 2021) making it somewhat unstable as the allied genus Dichanthium Willemet (1796) with its multi-spiculated racemes, solid pedicel and rhachis internode hardly differs from Capillipedium in absence of capillary branches in the inflorescence. However, there are certain giant forms of D. annulatum (Forssk.) Stapf showing typical paniculate inflorescences that also exhibit capillary branches. In this situation the generic delimitation becomes extremely challenging and almost impossible. Although it was placed in Capillipedium by Tiwari and Landge (2021) based on maximum number of morphological similarities, molecular work is required to confirm its placement in the genus. Capillipedium mistryi can be best compared with a non-Indian species, C. spicigerum Blake (1944) in longer racemes, but the latter has translucent rhachis and pedicel. The latter species is widely distributed from China to Australia (especially eastern territories) (Simon and Alfonso 2012). Coincidently, another new species, C. yashwantraoi Tarbej and Potdar (2021), that was published based on specimens collected from Amarkantak Hills, Madhya Pradesh, exhibit similar morphological features as C. mistryi. The present study is based on a comparison of the morphological characters of these two species, to investigate whether they are conspecific or not. The comparison drawn between the two is based on their protologues and study of the type materials (including digital images procured from BLAT, BSI and CAL herbaria). Material and methods Type specimens of C. mistryi and C. yashwantraoi were consulted at BLAT, BSI and CAL. They were compared based on morphological features to check for overall similarities and differences. High resolution digital images of both species were procured from respective herbaria (BLAT, BSI and CAL). The protologues of both species were critically studied and based on that a table of comparison was made, in which overall similarities are evident. Taxonomic treatment Capillipedium mistryi Tiwari and Landge (2021) Capillipedium yashwantraoi Tarbej and Potdar (2021) syn. nov. Flowering and fruiting October to December. Distribution Madhya Pradesh state, Hoshangabad district, Bori Wildlife Sanctuary and Anuppur district, Amarkantak; so far only known from Madhya Pradesh in India. Page 2 of 4 Specimens examined India, Madhya Pradesh, Anuppur district, Amarkantak, 22°45′15.7″N, 81°44′50.6″E, 1082 m a.s.l., 3 Nov. 2019, Shaikh Tarbej YCCSK 2076 (CAL and BSI); Hoshangabad district, Bori Wildlife Sanctuary, Bori Range, 22°15′ to 22°30′N, 77°45′ to 78°30′E, ca 500 m a.s.l., 15 Nov. 2019, A. P. Tiwari 35 (BLAT). IUCN threat assessment Data Deficient (DD) (Tiwari and Landge 2021). Notes Slender multi-spiculated racemes (comprising 11–25 sessile spikelets) with non-translucent, solid rhachis internodes and pedicels (Fig. 1). Discussion Based on a detailed morphological study of the characters of the habit, leaf sheath, ligule, leaf blade, inflorescences, raceme, rhachis internode, stamens, and the sessile and pedicelled spikelets (Table 1) of C. yashwantraoi and C. mistryi we concluded that there is no solid ground to maintain the former as a species distinct from the latter. It is interesting to note that both species were collected from the state of Madhya Pradesh and from similar habitats, viz. hill sides. Critical analysis of the description in the protologue and illustrations/images of the former species revealed that there are no strong characters enabling the separation of the two species, as they have all features in common (Table 1). Indumentum on vegetative parts and many a times on glumes is a plastic character and are not being constantly maintained in populations. The apex of the lower lemma in the sessile and pedicelled spikelets may vary from being obtuse to acute. The significant characters by shared by both species are the multi-spiculated racemes and solid rhachis internode and pedicel. Both of these characters make this species quite unusual in the genus and thus question its origin which is presently unknown. As hybridisation has been observed in this group, possibilities for the same with perhaps Dichanthium may be hypothesized. Based on the overall similarities, C. yashwantraoi is treated here as a heterotypic synonym of C. mistryi. To further comment on its distribution, apparently more field work across the state of Madhya Pradesh is required. Perhaps the species is frequent along the hilly areas of the state. After studying more individuals of the populations, including the type of C. mistryi, we found that mature pedicelled spikelets bear three perfect stamens and the length of the spikelet varies from 2.5 to 4.5 mm. However, according to the protologue of C. mistryi it has one aborted stamen in the pedicelled spikelet, along with the two perfect stamens. The abortion may be either due to environmental cause or a genetic defect. Anyway, this character is unstable and should not be used to distinguish between taxa. Apices of the lower lemma of the sessile spikelet do vary from being obtuse to acute even Figure 1. Holotype specimens. (A) Capillipedium mistryi Tiwari and Landge. (B) Capillipedium yashwantraoi Tarbej and Potdar. (© Directors, Blatter Herbarium (BLAT) and Botanical Survey of India). Table 1. Comparison of Capillipedium mistryi and C. yashwantraoi based on their protologues and the holotype specimens. Characters Habit Leaf sheath Ligule Leaf blade Panicle Raceme Rhachis internode and pedicel Sessile spikelet Pedicelled spikelet Stamens Capillipedium mistryi Capillipedium yashwantraoi Perennial, 50–130 cm high Keeled, 2.0–6.0 cm long Membranous Linear-elliptic 5.0–20.0 × 0.4–2.0 cm; midrib wide and prominent base-wards Open, 4.0–7.0 × 3.0–5.0 cm With 11–25 fertile (sessile) spikelets Solid (if at all grooved then not translucent), 1.0–2.0 mm long 2.5–3.0 × 1.0–1.2 mm 2.5–4.5 mm 3 Perennial, 60–120 (–140) cm high Keeled, 4.0–7.0 cm Membranous Linear to lanceolate 6.0–24.0 × 0.5–1.2 cm; midrib widened Open, 4.0–6.0 × 4.0–6.0 cm With 22–26 fertile spikelets Solid (non translucent), 1.0–1.2 mm 2.0–2.5 × 0.8–1.0 mm 3.0–3.2 × 0.8–1.0 mm 3 in the same inflorescence in the holotype. Pedicel length varies from 1.0 to 1.8 mm in the same inflorescence. The least number of spikelets we have found in a raceme is 11, but it may reach 26 as maximum. Care must be exercised when counting the number of spikelet since the racemes tend to disarticulate when mature which may cause error when counting. It is recommended to count spikelets before caryopses are set. BSI WRC for providing the high resolution digital images of the holotype and isotype. The first author (SNL) would like to thank Dr Asir Benniamin (scientist ‘E’, HoO BSI WRC) for his kind help and encouragement. Funding – We thank authorities of St. Xavier’s College (Autonomous) Mumbai for giving funding.. Acknowledgements – We thank authorities of St. Xavier’s College (Autonomous) Mumbai for providing library facilities. We are grateful to the directors, Botanical Survey of India CAL (CNH) and Shahid Nawaz Landge: Conceptualization (equal); Formal analysis (equal); Investigation (lead); Methodology (lead), Writing – original draft (lead), Writing – review and Author contributions Page 3 of 4 editing (lead). Arjun Prasad Tiwari: Conceptualization (equal); Formal analysis (equal); Investigation (supporting). Rajendra D. Shinde: Funding acquisition (lead); Resources (equal). Data availability statement This article contains no additional data. References Blake, S. T. 1944. Monographic studies on the Australian Andropogoneae, Part 1. – Univ. Queensland Dept Biol. Papers 2: 1–62. Bor, N. L. 1960. The grasses of Burma, Ceylon, India and Pakistan (excluding Bambuseae). – Pergamon Press. Clayton,W. D., Goverts, R., Harman, K. T., Williamson, H. and Vorontsova, M. 2019. World checklist of Poaceae. – Facilitated by the Royal Botanic Gardens, Kew. Kellogg, E. A. 2015 Poaceae. In: Kubitski, K. (ed.), The Families and Genera of Vascular Plants. – Springer, p. 311. Page 4 of 4 Landge, S. N. and Shinde, R. D. 2021. Synopsis of the genus Bothriochloa (Poaceae: Andropogoneae) in India. – Phytotaxa 516: 43–58. Landge, S. N. and Shinde, R. D. 2022a. 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