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| Decaisnina tomentosa M.D.Angeles, Tandang, Carab.-Ort., & Buot, in Tandang, delos Angeles, Buot, Devkota et Caraballo-Ortiz, 2022. Photos: Marjorie delos Angeles. |
Abstract
Background:
The extensive forests over limestone of the Samar Island Natural Park (SINP) on Samar Island, Philippines harbour a rich variety of unique species. In this contribution, we describe and illustrate a new Loranthaceous mistletoe, endemic to Samar Island named Decaisnina tomentosa, representing the 12th member of the genus reported to the Philippines.
New information:
This new species is similar to D. confertiflora (Merr.) Barlow with respect to the presence of shortly and densely off-white tomentose inflorescence and 6-merous flowers. However, it is unique amongst congeners in having tomentose and partially fused bracteoles which cover almost or entirely the ovary of individual flowers in the triads. To date, D. tomentosa seems to be restricted to the SINP and is only known from a handful of individuals. More studies are needed to properly assess the demography, host range, conservation status and phylogenetic position of this distinctive species of mistletoe.
Keywords: forest over limestone, island endemics, parasitic plants, Samar Island Natural Park, Santalales, taxonomy
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| Decaisnina tomentosa M.D.Angeles, Tandang, Carab.-Ort., & Buot. A Inflorescence with distal flowers in buds and proximal flowers at anthesis. B Inflorescence with flower buds. C Inflorescence in a secund raceme showing the tomentose rachis and bracts. D Close-up of bracts and bracteoles showing its tomentose nature. Note the tomentose indument covering all structures. E Twig with opposite leaves. Note the shiny surface of leaves with obscure venation. F Epicortical runner (right side) appressed against the stem of its host. Arrow points to a secondary haustorial connection. Photos: Marjorie delos Angeles. |
Decaisnina tomentosa M.D.Angeles, Tandang, Carab.-Ort. & Buot, sp. nov.
Diagnosis: Decaisnina tomentosa (Fig. 1) is similar to D. confertiflora (Merr.) Barlow with respect to the presence of shortly and densely off-white tomentose inflorescence and 6-merous flowers. However, the new species differs by its rounded ste, (vs. stem internode distinctly angular), cuneat leaf base (vs. truncate or slightly cordate at the leaf base) and corolla that is distinctly inflated teice (vs. slightly inflated at the base). Also, the new species has a longer corolla measuring 27.9–29.2 mm (vs. 16–20 mm). Highly distinct flowers that are subtended with a tomentose cup formed by the fusion of the bracteoles with slightly cucullate lobes and glabrous inside which almost or entirely cover the ovary of individual flowers, and corolla tomentose, double inflated at base and middle. We consider that the combination of these and other characters presented in Table 1 are significant for the recognition of this new species.
Etymology: The specific epithet “tomentosa” refers to the short soft indument densely covering the inflorescence of the new species.
Distribution: This new species is known only from the type locality at the SINP in Paranas, Samar Island. The SINP is a protected area under Proclamation No. 442. 2003, pursuant the National Integrated Protected Areas System Act of 1992 (Republic Act No. 7586).
Ecology: Regarding interactions with potential pollinators and seed dispersers, no floral visitors or fruit consumers were observed during our visit to the site. Given the morphological features of flowers and fruits, it is probable that they are pollinated and dispersed by birds. Systematic field observations and experimental studies are needed to assess pollinators and effective seed dispersers and to document interactions with other organisms.
Danilo N. Tandang, Marjorie delos Angeles, Inocencio, Jr. E. Buot, Mohan Prasad Devkota and Marcos A. Caraballo-Ortiz. 2022. Decaisnina tomentosa (Loranthaceae), A New Species of Mistletoe from Samar Island, Philippines. Biodiversity Data Journal. 10: e78457. DOI: 10.3897/BDJ.10.e78457
