Rafflesia kemumu Susatya, Hidayati & Riki, 2017

Susatya, Agus, Hidayati, Siti Nur & Riki, Septian, 2017, Rafflesia kemumu (Rafflesiaceae), a new species from Northern Bengkulu, Sumatra, Indonesia, Phytotaxa 326 (3), pp. 211-220 : 212-216

Rafflesia kemumu Susatya, Hidayati & Riki , spec. nov. ( FIGS. 1B, 1D , 2B, 2D , 3B , 4 , 5B, 5D )

Differs from a related species R. gadutensis by the absence of warts on the upper surface of the diaphragm, the pattern and arrangement of warts of windows near the diaphragm opening, and the presence of compound toadstool ramenta on the upper part of the perigone tube.

Type:— INDONESIA: Sumatra, Bengkulu, Northern Bengkulu, Palak Siring Forest, elev. about 485 m a.s.l, 3°25 ′ 25.5 ″ S, 102°15 ′ 45.7 ″ E. 10 November 2016, A. Susatya 2 (female flower, fruit) (holotype: HUB!), A. Susatya 1 (male flower) (paratype: HUB!).

Holoparasite. Male flower fully opened ca. 38.50–43.80 cm diameter. Perigone lobes 5,10.39– 12.59 cm long, 14.52– 18.58 cm wide, orange to dark orange colors. Warts of two sizes, whitish orange, small warts ca. 0.22–0.35 cm diameter surrounding large wart, large warts ca. 0.68–1.00 cm diameter, 7–9, across median of perigone lobes, large warts becoming smaller, and more distant to each other towards tip of perigone lobe, sometimes merged in middle of perigone lobe, small warts often merged to form long rectangular shapes, ca. 0.22 by 0.70 ‒ 1.50 cm ( FIG. 1B, D ). Perigone tube 13.80–14.20 cm high, colored lighter orange perigone lobe. Diaphragm ca. 10.38–12.63 cm wide, opening ca. 5.09–7.47 cm wide, color upper surface of diaphragm similar to perigone lobe, orange to dark orange, warts absent, 4 discontinuous rings of circular depressions lighter in color than their backgrounds ( FIGS. 1B , 2B ). The lower face of diaphragm dark orange, becoming very dark orange in the region just before the tip of the opening. Windows 4 discontinuous rings of whitish orange blots, blots more distant to each other toward to diaphragm opening, first ring consisting of compound toadstool ramenta, 0.65–0.82 cm wide, close to each other in region near tip of perigone tube, second ring consisting of toadstool ramenta, 0.64–0.81 cm wide, 0.48–0.53 cm long, distant to each other, the third ring with blots, 0.62–0.89 cm wide, 0.52–0.82 cm long, distant to each other, outer ring with circular blots, 0.16–0.20 cm wide, 0.48–1.04 cm long, 1.13–1.75 cm spaced apart ( FIG. 2D ). Disc ca. 7.96–8.38 cm diameter, orange, lighter color than perigone lobe, disc rim 1.80 cm high, raised, dark orange at the tip and becoming lighter toward its base. Ramenta simple broccoli-like ramenta, 0.51–0.64 cm high, ca. 0.11 cm wide at apex, sparsely occupied from base to middle of perigone tube; branched broccoli-like ramenta, 0.78–0.83 cm high, very rare, only at mid-zone of perigone tube; regular broccoli-like ramenta, 0.76–0.83 cm high, more numerous, distributed from near base up to top of perigone tube, near diaphragm; simple and compound toadstool ramenta at upper part of perigone tube ( FIG. 4 ). Processes 23, conical with rounded apex, dark orange at apex and becoming lighter orange towards base, two concentric rings and a single process in center of disc, outer ring with 15 processes, 1.29–1.39 cm high, 0.62–0.81 cm wide at base, 0.13–0.38 cm wide at apex, second ring with 7 processes, 1.54–1.84 cm long, 0.76–1.54 cm wide at base, 0.11–0.21 cm at apex, center 1.26 cm high, 0.94 cm wide at base, 0.22 cm at apex ( FIG. 5B, D ). Central column 3.10 cm high, 5.30 cm wide at base. Male flower 26 anthers within pollen sacs, ca. 0.80–0.90 cm diameter, grooves running down from their corresponding pollen sacs to interior annulus, grooves 0.80–0.90 cm wide at top, 0.40–0.50 cm at the base near the annulus interior. Female flower grooves replaced by lines stretching from the lower disc to the annulus interior. Fruit 4.47 cm high, 5.50 cm wide at apex, ca. 4.82–5.53 cm wide at base; ovary oval, 2.13 cm long, 0.98 cm wide. Annulus interior 0.44 cm high, exterior 0.24 cm high.

Etymology:—The specific epithet is named after a village near the location where the holotype specimen was collected, Kemumu. The people of Kemumu rely on the continuity of a water supply from the Palak Siring watershed for their rice fields.

Distribution and Habitat:— Rafflesia kemumu is a holoparasitic plant, with Tetrastigma pedunculare (Wall ex Lawson) Planch. as its host (herbarium specimen, Gin-2, HUB!). The holotype was collected from the Palak Siring area, which is considered a lowland rain forest, and also as a part of the Bukit Daun Protection Forest. Common forest trees where the holotype was collected included: Microcos laurifolia (Hook.f. ex Mast.) Burret ( Tiliaceae ), Elateriospernum tapos Blume ( Euphorbiaceae ), Rinorea anguifera (Lour.) Kuntze ( Violaceae ), Villebrunea rubescens Blume ( Urticaceae ), Macaranga triloba (Blume) Mull. Arg. ( Euphorbiaceae ), and Ficus ribes Reinw. ex Blume ( Moraceae ). Four populations of R. kemumu occur in the Palak Siring area consisting of 2 − 12 flower buds per population. The species is reported to occur in the Kuro Tidur area as well, also part of the Bukit Daun Protection Forest, and at Ipuh Production Forest, Muko-Muko Regency, Northern Bengkulu. The Kuro Tidur area and Ipuh are ca. 40 and 150 km, respectively, northwest of the Palak Siring area. However, the Ipuh record should be further examined to define whether it is R. gadutensis or R. kemumu , since Ipuh is close to the former gold mine in Northern Bengkulu, where Meijer identified a photograph by Schaefer in 1934 as R. gadutensis ( Meijer 1997) .

Phenology:— Rafflesia kemumu flowers during any month of year, regardless of the season. However, flowering occurs more frequently from August to November than during other months and rarely in December.

Conservation:— Nais (2001) categorized all Indonesian species of Rafflesia as Vulnerable (VU), but Susatya (2011) recognized them as Critically Endangered (CR), except for R. arnoldii (as VU) and R. pricei Meijer (as Least Concern, LC), due to their low population size, high mortality, and limited geographical distributions. We classify R. kemumu as CR based on these criteria. The Palak Siring area is a famous tourism destination for Northern Bengkulu. Of the four known populations of R. kemumu , one is very close to a trail within the Palak Siring Forest and is heavily visited and severely impacted from unguided tourists. The locations of the other three populations are more remote and occur in more pristine habitat.

Figures

FIGURE 1. The color of perigone lobes and their wart patterns on the first day of flowering for Rafflesia gadutensis (A, C) and R. kemumu (B, D). Red maroon perigone lobes are R. gadutensis (A) and dark orange lobes are R. kemumu (B). Large warts (lw) are surrounded by small warts (sw), which are often merged to form distinctive long rectangular shapes on R. kemumu (D). Rafflesia gadutensis was photographed by the late Prof. Kamarudin Mat-Salleh of UKM at Mohammad Hatta Forest Garden, near Gadut area, West Sumatra. Photo B by S. Riki and D by A. Susatya.

FIGURE 2. The upper surfaces of the diaphragm of R. gadutensis (A) and R. kemumu (B). Light pinkish with red margin warts (w) are present on R. Gadutensis (A). The warts are absent on R. kemumu. Concentric serries of circular depressions with light orange colors are a distinctive feature for R. kemumu (d) (B). The windows of R. gadutensis (C) and R. kemumu (D). Two concentric rings (cr) near the diaphragm of white blots that are often merged for R. gadutensis (C), and that are circular blots and distant to each other for R. kemumu (D). Photos A and C were respectively provided by the late Prof. Kamarudin Mat-Salleh, and R. Mahyuni, and photos B and D by A. Susatya.

FIGURE 3. The distribution of toadstool ramenta on Rafflesia gadutensis (A) and R. kemumu (B). Toadstool ramenta (tr) were only found on the inner surface of the diaphragm (d) in R. gadutensis (A), whereas they were found on the inner surface of the diaphragm (d) and the upper part of the perigone tube (pt) in R. kemumu (B). The border between the perigone tube and diaphragm is marked by b. Photo A by the late Prof. Kamarudin Mat-Salleh of UKM and B by A. Susatya.

FIGURE 4. The ramenta structures of R. kemumu and their distributions along the inner surface of the perigone tube. Ramenta types: simple broccoli-like (bs), branched broccoli-like (bb), regular broccoli-like (b), simple toadstool (st), and compound toadstool (ct1, ct2). The photos show ramenta on cross-sections of the perigone tube: from base to mid part (A) and from middle to the upper part of the tube (B). Photos and drawings by A. Susatya.

FIGURE 5. The structure and arrangement of processes on the disc of R. gadutensis (A, C) and R. kemumu (B, D). The flat and truncate apices of the processes for R. gadutensis (C) and the slender, conical shaped processes with rounded apices for R. kemumu (D). Photos A and C by the late Prof. Kamarudin Mat-Salleh and B and D by A. Susatya.