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| Dipcadi mukaianum Shelke, S.R.Yadav & Lekhak, in Shelke, Tamboli, Surveswaran, Yadav, Choo, Pak et Lekhak, 2024. |
Abstract
Dipcadi (Scilloideae: Asparagaceae) is a genus of bulbous monocots with approximately 40 species, of which 13 occur in India. Species delimitation within the genus has been troublesome hindering a comprehensive phylogenetic analysis. The most recent phylogeny of the subfamily Ornithogaloideae included six species of Dipcadi only from Africa. Here, we reconstructed the phylogeny of Ornithogaloideae including 23 accessions comprising 13 recognized taxa (11 species and two varieties) of Indian Dipcadi. The phylogenetic analyses were based on nucleotide sequences of three plastid regions (rbcL, matK and trnL-F spacer) and one nuclear region (ITS). Pseudogaltonia clavata exhibited sister relationship to Dipcadi. Our combined nuclear + plastid dataset analyses revealed a monophyletic Dipcadi with five clades, Clade I-V. Clade I, II and III included mainly Indian species whereas Clade V included mostly African species. Clade IV comprised D. serotinum. Clade I included nine taxa including our newly described species, D. mukaianum. The new species was phylogenetically placed with D. erythraeum, D. saxorum and D. ursulae. Morphologically, the species resembled D. montanum and D. ursulae but differed in characters such as tepal cohesion, number of ovules per locule and foul-smelling flowers. Clade II and III included 11 and six taxa, respectively. D. erythraeum which has a native range from Egypt to western India was found in Clades I and V. The widespread Dipcadi species, viz. D. erythraeum and D. serotinum showed polyphyly however, the monophyly of Dipcadi is established. Our studies suggest that additional molecular markers (plastid as well as nuclear) should be tested for their taxonomy utility. Further work on the historical biogeography of Dipcadi on the subfamily Ornithogaloideae with more genetic data will yield insights how aridification of the landscape would have shaped the evolution of the geographical clades.
Keywords: cpDNA, Dipcadi, ITS, Monocots, Scilloideae, Taxonomy
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| Dipcadi mukaianum. a Inflorescence; b Side view of the flower showing reflexed tepals; c Bract; d Inner tepal; e Outer tepal; f Flower split open and gynoecium removed; g Stamen (adaxial surface); h Stamen (abaxial surface); i Pistil; j Infructescence; k T.S. of ovary; l Seed m Bulb; n Leaf |
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| Dipcadi mukaianum a Habitat; b Habit; c Inflorescence; d Infructescence; e Front view of the flower showing trilobed stigma and reflexed tepals; f L.S. of the flower showing pistil with small stipe |
Dipcadi mukaianum Shelke, S.R.Yadav & Lekhak sp. nov.
Ecology: Dipcadi mukaianum grows near the Hiranyakeshi River, preferring sandy and gravelly soil and grasslands with Hypoxis aurea Lour., Iphigenia indica (L.) A.Gray ex Kunth, I. pallida Baker, Ledebouria revoluta (L.f.) Jessop and Curculigo orchioides Gaertn.
Etymology: The species is named after Prof. Yasuhiko Mukai, Osaka Kyoiku University, Osaka, Japan for his contributions in the field of plant molecular cytogenetics in general and wheat cytogenetics in particular.
P. E. Shelke, A. S. Tamboli, S. Surveswaran, S. R. Yadav, Y.-S. Choo, J. H. Pak and M. M. Lekhak. 2024. Molecular Phylogenetic Reconstruction improves the Taxonomic Understanding of Indian Dipcadi (Asparagaceae) and reveals A New Species from the bank of Hiranyakeshi River, Maharashtra, India. Journal of Plant Research. 137; 829–845. DOI: doi.org/10.1007/s10265-024-01558-9
