Scientific name: Camellia bugiamapensis Orel, Curry, Luu & Q. D.Nguyen
English name:
Vietnamese name: Trà bù gia mập
Other name:

Perennial, medium to large evergreen shrubs, to 7 m high, with upright habit, sparsely branched, sometimes multi-stemmed; main stem to 20 cm thick at base; secondary branches slender and ascending at ca. 45°, although branch terminals are semi-pendu­lous; mature bark smooth, with dull sheen, light brown with gray to whitish blotches, usually with some lichen growth; new shoots thin, initially light green, later gray to brown, glabrous, shiny, turning dull; mature branches concolorous to trunk. Petioles falcate, short and thick, 1—1.5(—2) X 0.3—0.5 cm, distally light green, proximally medium green, on older leaves brown and sometimes corky, with a variably deep longitudinal channel on adaxial side; axillary leaf buds small, rudimentary, laterally compressed, <1 mm diam., initially green, later turning brown to dark brown; terminal leaf buds light to mid-green, glabrous, with scales not prominent; buds slightly falcate, with sharp apex, 0.5—1.2 X 0.3—5(—0.7) mm; developing leaves light green with distinct sheen, glabrous, rather thin, elliptic to oval, irregularly serrate, less so proximally, margins proximally slightly undulate, some juvenile leaves with pronounced unevenly serrate leaf margins; mature leaves elliptic, oval to widely elliptic, 18— 27.5(—29.5) X 12—14(—15) cm, irregularly serrate, more so distally, with margins slightly undulate proximally, glabrous, rather thin, slightly pitted, adaxial surface mid- to dark green, shiny, lighter green and dull below; leaf apex widely cuspidate to almost acuminate in less developed leaves on lower branches; leaf base obtuse or rounded, some leaves somewhat amplexicaul; midrib narrow, sunken and light green adaxially, prominent and light green to yellowish green abaxially, glabrous, 1.5—3.5 mm wide proximally, <1 mm wide distally, not shiny, rather dull; secondary venation pinnate, distinctly brochi- dodromous, with (7)8 to 11 pairs of veins, adaxially sunken, abaxially prominent; tertiary venation adax- ially indistinct, more prominent and branched abaxially, rather sparse and uneven, but more prominent marginally; areolation well developed, with meshes unevenly tetragonal, oblong to triangular of relatively inconstant size, maximum areole dimen­sions (0.75—)1.5—2.5 X 1—1.5 cm, decreasing toward leaf margins. Flowers slightly oblong in lateral section, terminal, mostly solitary, but some branches with 3 to 5 flower buds, lacking scent; some mature and all senescing flowers with strongly reflexed, outward curved petals; bracts undifferentiated and distinct; flower buds not numerous, unevenly orbic­ular, terminal, sessile, dark yellow, with prominent scales; peduncle short and thick, 3—5 X 3—4 mm, dark green, later brown, initially entirely covered by perules, so the flowers appear to be sessile; perules partially deciduous on mature flowers, up to 7, undifferentiated, greenish to yellow brown, concave, lunate, mostly glabrous, sometimes marginally frayed, striations lacking, 0.9—2.5 X 1—2(—2.5) cm; transi­tional petaloids 4, distinct, yellowish to green, slightly rigid, with faintly visible venation, concave, variable in shape and size, 2—3 X 2—3 cm, basally overlapping, finely hairy, the margins frayed, finely ciliate; basally overlapping to form a wide and shallow cup; flowers 5-6(—6.5) cm diam., ca. 3 cm thick, bright yellow, later darker; senescing flowers dark yellow, shiny, waxy, with partially translucent, lighter yellow petal margins, hard and rigid, easily damaged; mature flowers with reflexed, outward curved petals; petals 9 to 11, arranged in a random, uneven spiral, unevenly ellipsoid to almost oblong, waxy, brittle, thick, thinner on the margins where they are almost translucent, strongly concave, striations absent, glabrous, with margins sparsely ciliate, without emargination, to 4 X 2.5-3.5 cm, the inner petals proximally attached to stamens for 2-2.5 cm, forming a yellow cupule; stamens ca. 50 to 100, bright yellow, in tight circular formation 2.5-3 cm diam.; filaments bright yellow, thin, glabrous, (2-)2.5-3.5(—4) cm; outer filaments attached to the inner petals for 2-2.5 cm, some outer filaments arise proximally from inner petals; anthers small but distinct, <1 mm, bright yellow, later light brown, glabrous, basifixed; style single, columnar, slightly sinuous, 13-18 X 2-2.5 mm proximally, light yellow, distally green, finely tomentose, with white hairs; stigma 5-lobed, consisting of 5 small, flat, unevenly circular discs, yellow to brownish; ovary superior,2.5-3x3-4 mm, resting on a 1-2 mm thick base, yellow, glabrous, shiny, with 5 to 6 lobes, each locule containing 2 ovules. Mature fruit unevenly globose, with prominent, brown stylar remnant, with ridging between individual valves also prominent, yellowish brown, with unevenly concentric, dark brown- pigmented markings, glabrous, 6-valved, 2-2.5x 2.5-3(—4) cm.

Camellia bugiamapensis Orel, Curry, Luu & Q. D. Nguyen.
A. Adult leaf, primary, secondary, and tertiary venation, adaxial view. —B. Adult leaf, leaf base and petiole with primary and secondary venation, abaxial view. —C, D. Adult leaf, leaf apex variation with primary, secondary, and tertiary venation, abaxial view. —E. Terminal leaf bud. —F-H. Undifferentiated perules. —I, J. Transitional petaloids. —K-M. Petals. —N. Developing flower bud. —O. Stamens with adjoining petal. —P. Adult gynoecium, schematic view. —R. Adult fruit capsule. —S. Adult branch with flowers and leaves. Drawn from the holotype Luu Hong Truong, Nguyen Quoc Bat, G. Orel & A. S. Curry 698 (SGN, NSW).

Distribution and ecology

Camellia bugiamapensis is known only from the type location, which is situated about 1 km from the Cambodian border in the Bu Gia Map National Park, Binh Phuoc Province, Vietnam. The new species was discovered in disturbed lowland tropical forest on elevated ground adjacent to a watercourse.

IUCN Red List category

The known AOO for this new species is estimated to be less than 1 km2. Despite a further search of the area around the type locality, only a few mature plants were located. We estimate that the total population of the species is fewer than 50 individuals and that it would qualify for assessment as Critically Endangered (CR) under criterion D (IUCN, 2011). However, the area is adequately protected by inclusion in the Bu Gia Map National Park, and this suggests that the IUCN category of Endangered (EN) would be more appropriate (IUCN, 2011).

Phenology

Camellia bugiamapensis was collect­ed in flower in December. The first author has photographs of mature fruit taken three months later.

Etymology

The specific epithet of the new species refers to the location of discovery, namely to the Bu Gia Map National Park in Vietnam.

Discussion. The geographic areas delineated for the yellow-flowering species of Camellia, most of which were placed in Camellia sect. Archecamellia Sealy (sensu Sealy, 1958; Ming & Bartholomew, 2007), Camellia sect. Chrysanthae Hung T. Chang (sensu Chang & Bartholomew, 1984), and Camellia sect. Luteoflorae Hung T. Chang (sensu Chang & Bartholomew, 1984), comprise the southern provinc­es of China and the northern provinces of Vietnam (Sealy, 1958; Chang & Bartholomew, 1984; Gao et al., 2005; Ming & Bartholomew, 2007). The newly proposed species, C. bugiamapensis, brings the total of yellow-flowering Camellia species indigenous to southern Vietnam to between six and eight (two early records are unconfirmed). Recent collections made on Da Lat Plateau are also likely to include further yellow-flowered species. This local concentration of yellow-flowered species in southern Vietnam is significant, as it designates this phytogeographic area as a major repository of indigenous Camellia species. It also raises a number of questions regarding the evolution and origins of the genus Camellia and Theaceae in general.