Diagnosis
Rafflesia balatociana is distinguished from closely related
species by a combination of characters: bilobed outermost bract (entire
in R. aurantia, R. banaoana and R. consueloae ), diaphragm
discolorous from perigone lobes (concolorous in R. aurantia andR. banaoana ), a weakly dome-shaped disk (shallowly depressed
centrally in R. aurantia , conspicuously dome-shaped in R.
banaoana ), a dark red, leathery and distally ‘pockmarked’ (indented)
upper disk surface (creamy-white to pale pink, covered with brown
acicular hairs throughout in R. consuelaoe , ivory to brownish
yellow in R. banaoana ), a doubly-dentate disk rim with bristles
(vs. crispate in R. consueloae and R. aurantia , with
minute brown hairs in R. banaoana ), a long strap-shaped lacuna on
the annulus interior (contracted and blunt in R. aurantia andR. consueloae , long and basally-expanded in R. banaoana ),
and an annulus exterior without a basal ridge (basal ridge prominent inR. banaoana ).
Endophytic holoparasite (devoid of a vegetative body).Mature bud 10–15 cm diameter. Cupule c. 2.5–3 cm
high, 5–6 cm wide. Bracts dark brown to black, in a set of 5
imbricate whorls, 5 bracts per layer, outermost smallest, c. 2–3 cm
long by 4.5 cm wide, innermost bilobed about 2 cm deep, largest, c.
9–10 cm by 8–9 cm. Flowers 25–35 cm diameter when fully
expanded, 5–6 cm high. Perigone tube slanted, 5–7 cm long.Perigone lobes 5, 8–10 cm by 10 cm, 3-6 mm thick, ochre when
young, reddish-brown when mature, apically recurved, broadly orbicular,
basally valvate, with margins darker in color, entire, covered with
conspicuous, highly embossed, small, round, elongated, sharply-edged
warts, white in color, denser near the base. Diaphragm 16–18
cm diameter, 3–6 cm wide from aperture rim to base of perigone lobe,
5–9 mm thick, background discolorous, darker from the perigone, outer
surface with highly embossed sharply-edged and fence-like warts, 1-2 mm
high. Diaphragm Aperture 9-10 cm diameter, margin entire, white
becoming concolorous with the diaphragm. Windows absent.Ramenta reddish brown, simple filiform, 2–5 mm, longer on the
lower perigone tube, simple and filiform, sometimes bi-lobed, shorter on
the lower surface of the diaphragm; ramenta confluent at the base,
multi–lobed above. Disk 7-8 cm diameter, 1–1.5 cm thick, pale
pink when young, dark red when mature, centrally dome–shaped, rim
extended horizontally, margin darker in color, doubly-toothed with
bristles, the upper surface smooth, shiny and leathery, ‘pockmarked’ at
the distal portion, centrally with conspicuous processes about 0.5–1
cm, the undersurface white in the middle portion near the neck of the
column, brownish yellow to reddish brown in the outer zone, with minute
white hairs. Processes 10–15, concolorous with disk, apex with
a few bristles, those of the female flower generally shorter, 5–6 cm,
polymorphic, conical on the outer zone, lobed and flattened on the inner
zone; those of the male flower longer, conical, pointed apically.Male flower generally larger (to 35 cm), without vestigial
ovary, anthers 17–18, 3–5 mm diameter, globose, attached to a
brown sub-structure about 5–8 mm wide, immersed in anther sulci 7–8 mm
long and 5–8 mm wide; neck of the column 7–8 mm height, 4-4.5
cm diameter; lamella 18–20, 0.3–1 cm long from the neck margin,lacuna (or grooves between the lamella on annulus interior)
1.2–1.8 cm long and 0.3–1 cm wide, glabrous; interior annulus
structure similar in size from the disk, 7–8 cm diameter, surface with
small bristles, about 3 mm, reddish–brown becoming darker towards the
margin, curving upward, with minute hairs; exterior annulus
structure 1–2 cm from the edge of the interior annulus structure,
concolorous with the disk’s upper surface, glabrous, devoid of ramenta.Female flower smaller (c. 25 cm), with vestigial white anthers
in narrow grooves along the disk’s undersurface; neck of the
column 7–8 mm height, 3–3.2 cm diameter, margin lobed;interior annulus structure of
similar size to the disk, 7 cm in diameter, reddish-brown in color,
surface glabrous but hispidulous along the margin, grooves strap-shaped,
1.7 cm long, 0.4–0.5 cm wide; exterior annulus structure similar
to the male flower, ovary 5 cm wide, 1.2 cm height,
lunate–triangular, acutely angled. Fruit and seedsnot observed.