Rafflesia parvimaculata, Sofiyanti & Mat-Salleh & Mahmud & Mazlan & Ros & Hasein & Burslem, 2016

Sofiyanti, Nery, Mat-Salleh, Kamarudin, Mahmud, Khairil, Mazlan, Nor Zuhailah, Ros, Mohd., Hasein, Albukharey & Burslem, David F. R. P., 2016, Rafflesia parvimaculata (Rafflesiaceae), a new species of Rafflesia from Peninsular Malaysia, Phytotaxa 253 (3), pp. 207-213 : 210-211

Comparison of R. parvimaculata with related species

In this paper we describe the new species Rafflesia parvimaculata , which is distinguished from other species in the genus by the presence of numerous small and spatially distinct warts on the perigone lobes. The proposed name for the new species reflects this character. To confirm the distinctiveness of R. parvimaculata from its congeners in Peninsular Malaysia we examined the expression of morphological characters on specimens of R. cantleyi and R. azlanii . We found that the states of three characters diagnose them as distinct species: the size and pattern of warts on the perigone lobes, window pattern and ramenta. R. parvimaculata shows the lowest extent of the perigone lobe covered by warts (30–41 % of total area) but the number of warts per perigone lobe is the highest of the three species (84–98). Hence this species is characterised by possession of numerous small warts ( FIG. 2B ). By contrast, R. azlanii has the greatest extent of wart coverage on perigone lobes (58.2–72.5 %), but a low number of distinct warts (9.5–13) because they appear to have coalesced into a small number of clusters ( FIG. 3A ). R. cantleyi has an intermediate cover (41–64 % of perigone lobe) and number (26–61) of distinct warts per perigone lobe. Hence R. cantleyi ( FIG. 3D ) is distinguished by warts that are smaller and less aggregated than those of R. azlanii ( FIG. 3A ) but larger than than those of R. parvimaculata ( FIG 2A ).

The structure and distribution of warts on the perigone lobes of other Rafflesia species are very different to those we have reported here for R. parvimaculata . The warts of most Rafflesia species identified from Indonesia, Malaysia, Thailand, and the Phillipines are not clearly visible because their color is the same as that of the perigone lobes. R. pricei ( Meijer 1984) , from East Malaysia and R. hasseltii from Indonesia have clear white warts but the pattern they form on the perigone lobes is different to that of R. parvimaculata . R. pricei has numerous elongated white warts ( Meijer 1984), while R. hasseltii has scarce and large white warts ( Sofiyanti et al. 2007). Most of the Rafflesia species from the Philippines have numerous warts on the perigone lobes, but the warts have a rough texture, and are smaller in size and displayed in a different pattern on the perigone lobes than in R. parvimaculata .

The differential pattern of warts on the perigone lobes corresponds to that on the window among the three species of Rafflesia from Peninsular Malaysia that are compared explicitly in this paper. Therefore warts expressed on the window, as well as the wart on perigone lobes, were smallest and most clearly spatially distinct, especially towards the ramenta, in R. parvimaculata , well-spaced and larger in R. cantleyi and coalesced into larger units in R. azlanii ( FIG 3B ). The presence of a red ring near the aperture is also diagnostic for R. parvimaculata ( FIG 2B ) and R. cantleyi ( FIG 3E ), but not for R. azlanii ( FIG. 3B ), which confirms the descriptions of Adam et al. (2013) and Latiff & Wong (2003) for the latter two species.

Comparison of the structure and arrangement of the ramenta among three Rafflesia species from Peninsular Malaysia supports the recognition of R. parvimaculata as a distinct species. The ramenta of R. parvimaculata are slender, capitate, unbranched, white in color and densely aranged ( FIG. 2D ). The ramenta of both R. azlanii and R. cantleyi are branched, and the lower ramenta are dark red in color and loosely arranged ( FIG. 3C and FIG 3F ). Dark red ramenta are characteristic of all species of Rafflesia from Thailand and some of the Indonesian and Philippines species. White ramenta are found in R. hasseltii from Indonesia and R. lobata from the Philippines, however their characteristics are different from those R. parvimaculata . The ramenta tip of R. hasseltii is rough with darker red stalk towards the base, while the ramenta of R. lobata are shorter and smaller ( Galang & Madulid, 2006) than in R. parvimaculata These comparisons suggest that the structure, color and arrangement of ramenta are useful diagnostic characters for separating Rafflesia , particularly those that have overlapping distributions in Peninsular Malaysia.

Figures

FIGURE 2. Morphology of R. parvimaculata sp. nov.A. Mature bud, B. Male flower fully open, C. Inner side of floral perigone tube of male flower, D. Unbranched ramenta, E. Upper surface of disk showing processes of male flower, F. Lower surface of disk showing anthers (insert: pollen grain). Scale bars: A, C 5 cm; B 10 cm; D 1 cm; E, F 2,5 cm (Specimens: A not collected; B–E LJ4 a1; F LJ4 f3).

FIGURE 3. Morphology of R. azlanii (A–C), (Nery and Zuehailah, Lebay, Perak UL6), A. Mature flower, B. Window pattern, C. Aperture showing dark ramenta near the base of the disk; (D–F) R. cantleyi. (Mohd. Ros Sungkai, Pahang, AHS1 a8). D. Mature flower, E. Window pattern, F. A section of the inner side of the perigone tube showing window warts and dark red ramenta.