Scientific name: Camellia duyana Orel, Curry & Luu.
English name:
Vietnamese name: Trà duy
Other name:

Perennial, medium to large evergreen shrub, 12­15 m high, with upright habit, well branched, usually multi-stemmed; the main stem to 50 cm thick at base; secondary branches heavy and ascending at ca. 45°; mature bark smooth, with dull sheen, reddish to light cinnamon, usually with heavy lichen growth; new shoots thin, reddish brown, glabrous, shiny, turning reddish gray on semi-mature branches; mature branches concolorous to trunk. Petioles linear to slightly falcate, proximally slightly twisted around its longitudinal axis, light green abaxially, 0.7-1.1 cm X 2.5 mm, mid-green adaxially, with a light brown, shallow, sometimes corky, 1-1.5 mm wide, and ca. 1 mm deep channel; axillary leaf buds small, rudimen­tary, laterally compressed, <1 mm diam., green to dark brown; terminal leaf buds mid-green, with unevenly distributed purplish areas; scale margins hairy, slightly falcate, with sharp apex, 4.5-5 X 1- 2(—2.5) cm; developing leaves light green, with distinct sheen, glabrous, coriaceous, narrowly ellip­tic, distally irregularly serrate, less so proximally, with margins slightly undulate distally; mature leaves narrow elliptic to elliptic, glabrous, slightly coria­ceous, 10-13.5(—14.5) X 3.9-4.7(—5) cm, irregularly and finely serrate, more so distally, with margins undulate; adaxial surface mid-green, shiny, lighter green and shiny below; leaf apex variable, cuspidate; leaf base variably acute to cuneate; midrib narrowly sunken adaxially, prominent abaxially, 1.5-2.5 mm wide proximally, <1 mm wide distally, light green, dull, with occasional brownish areas on both sides; secondary venation pinnate, distinctly brochidodro- mous (Hickey, 1979), with 9 to 12 pairs of veins, adaxially sunken, abaxially slightly prominent; tertiary venation indistinct, rather sparse, unevenly distributed, adaxially sunken, more prominent at leaf margins, abaxially almost invisible to slightly prom­inent; areolation well developed only toward leaf margins, with meshes unevenly tetragonal to hexag­onal, of relatively inconstant size; maximum areole dimensions 0.7 X 3 mm, with areole size decreasing toward leaf margins. Flowers sessile, terminal and axillary, mostly solitary, lacking scent; senescing flowers with reflexed petals and large, distinct perules; flower buds numerous, orbicular, horizontal or upright, mostly green but whitish toward distal end; flowers 6.5-7.5(—8) cm diam., white to off-white, soft, crinkly, opaque to translucent toward margins, thicker toward center; petals 5 to 8, arranged in 2 whorls, reflexed in mature flowers, glabrous, some­times emarginate, overlapping proximally, lacking midrib but with visible, fanlike longitudinal striations that are concolorous and abaxially slightly raised; petals of outer whorl 3 to five, 3-3.5 X 1.8-2.5 cm, slightly concave, sometimes asymmetric, elliptic to obovate in shape, proximally fused for 4-6 mm to each other, otherwise free; petals of inner whorl 2 to 3, relatively variable in size, 3-3.3 X 1.5-2.5 cm, slightly concave, slightly asymmetric, narrowly ellip­tic to distinctly obovate, basally attached to stamens for 2-3 mm; perules undifferentiated, arranged in 3 loose and uneven whorls of 3 perules each; perules of outer whorl unevenly orbicular, slightly emarginate, of slightly varying sizes, concave, sometimes proxi­mally overlapping, hairy on both surfaces, mostly brown, with some green areas randomly distributed, with keel and striations lacking, to 4 X 6-7 mm, with margins becoming frayed, persistent on newly opened flowers, deciduous shortly after; perules in middle whorl unevenly orbicular to ovate, distinctly emar- ginate, of slightly varying lengths, concave, proxi­mally overlapping, rigid, finely tomentose, not entirely woody, dark brown, with a horizontally oriented line of lighter discoloration, 8-9 X 12-14 mm, persistent on newly opened flowers, deciduous shortly after; perules in inner whorl unevenly ovate to elliptic, concave, proximally overlapping, rigid, but not entirely woody, hairy, dark to mid-brown, with margins translucent and wavy, to 15 X 18-20 mm, persistent on newly opened flowers, deciduous shortly after; stamens fewer than 50, glabrous, yellow, in a circular series 2.5-3 cm diam.; filaments yellow, thin, 8-16 mm, almost free, basally fused for 2-3 mm, partially proximally joined to inner petal whorl; anthers very small, indistinct, <1 mm in diam., dark yellow, later brown, dorsifixed, although some stamens appear to be basifixed; styles 3(to 4), 10­12 X (1-)2-3 mm, less wide distally, free to base, finely tomentose, whitish yellow; stigma brown to dark brown, almost black, indistinct; ovary superior, almost diamond-shaped, (3-) 4- or 5-carpellate, finely and densely yellowish tomentose, with fine longitu­dinal striations proximally, 2.5-3.5 X 4-5 mm. Immature fruit unevenly globose to elliptical; mature fruits and seeds not seen.

Camellia duyana Orel, Curry & Luu.

A. Adult leaf, primary and secondary venation, adaxial view. —B. Adult leaf, primary, secondary, and tertiary venation, adaxial view. —C. Adult leaf, primary, secondary, and tertiary venation, abaxial view. —D. Terminal leaf bud. —E. Perules, outer whorl. —F. Perules, middle whorl. —G. Perules, inner whorl. —H, I. Petals, outer whorl. —J, K. Petals, inner whorl. —L. Corolla and part of androecium. —M. Stamens. —N. Adult gynoecium. —O. Lateral view of mature flower, schematic diagram. —P. Branch with flowers and leaves. Drawn from the holotype G. Orel & Nguyen Van Duy 0719 (NSW, SGN)

Distribution and ecology

Camellia duyana is known only from the type location, in Lam Dong Province, some 40 m below the ridge of an unnamed mountain on Da Lat Plateau. This new species occurs as part of dense understory vegetation situated in a less dense area of rainforest, with filtered sunlight reaching the ground during the midday hours. The species seems to thrive in poor, wet, but well-drained soils. It may be pollinated by bees (so far unidentified), as a small number of these insects were observed in the vicinity.

IUCN Red List category

The current area of occupancy (AOO) for this species is estimated to be less than 1 km2. Despite a further search (in 2011) of the area around the type locality, only two additional mature plants were located. The site is not within any national park or reserve and is subject to logging and other human disturbance. Given this situation, we consider the IUCN category of Critically Endangered (CR) to be appropriate under criterion D and possibly E (IUCN, 2011). The first author was unable to find another specimen of Camellia duyana in any Vietnamese herbarium.

Phenology

Camellia duyana was collected in flower in late November. The relatively large number of almost mature flower buds at the time of collection may indicate that December to January is the main flowering period for this species. No mature fruits or seeds were found.

Etymology

The specific epithet honors Mr. Nguyen Van Duy, a member of the Lam Dong Provincial Council and the co-discoverer of this new species.

Discussion

The newly proposed species, Camel­lia duyana, was found outside of, but close to, the geographical area considered by Sealy (1958: fig. 3) to be the natural range of species in his Camellia sect. Heterogeneae (see also Gao et al., 2005). Although C. duyana shares a number of morpholog­ical characteristics with species belonging to Camel­lia sect. Camellia (L.) Dyer, Camellia sect. Pseudo­camellia Sealy, and Camellia sect. Paracamellia Sealy, these are rather superficial. Dissimilarity in the mode of stamen attachment (free above a shortly fused base) justifies the exclusion of C. duyana from the abovementioned sections and supports placement into Camellia sect. Heterogeneae (Sealy, 1958).