Camellia dakplaoensis Luu, T.T.H.Nguyen & Th.H.Nguyen, 2025

Camellia dakplaoensis Luu, T.T.H.Nguyen & Th.H.Nguyen , sp. nov. ― Fig. 2 View FIGURE 2

Type:— VIETNAM. Dak Nong Province: Dak Glong District, Dak P’lao Commune , Ta Dung National Park , 11°50’57”N 108°00’52”E, 1520 m in elevation, 11 March 2021, Nguyen The Hien & Ho Dinh Bao NTH-2021-01 ( holotype SGN!; isotypes SGN!, PHH!, Herbarium of the Faculty of Agriculture and Forestry, Tay Nguyen University!) GoogleMaps .

Camellia dakplaoensis closely resembles C. langbianensis in overall tree habit, leaf and flower size, and flower coloration but it differs from the later in having flowers plain yellow ( versus yellow with pink pigmentation on edges), pedicels bearing 4–5 lanceolate bracteoles, each 15–18 mm long and 4–6 mm wide ( versus 2–3 ovate to triangular bracteoles, 2.0– 2.5 mm long and 2.5–3.0 mm wide), sepals glabrous on the adaxial surface with a cuspidate apex ( versus adaxially pubescent with a rounded apex), petals ovate to widely orbicular and adaxially glabrous ( versus suborbicular to pentagonal and adaxially tomentose), filaments wholly yellow and glabrous ( versus orange-red at the base, with inner filaments pubescent basally), and capsules distinctly ridged ( versus slightly ridged).

Description:— Shrub or small tree up to 6 m high, evergreen, sparsely branched; branches slender; young branches light green, glabrous; mature branches whitish grey. Leaves alternate; blade narrowly lanceolate to narrowly oblongelliptic, glabrous on both surfaces, adaxially green, abaxially pale green, 20–32 cm long, 5–5.5 cm wide, margins obscurely serrate, apex caudate or acuminate, base acute, decurrent onto petiole, midrib sunken adaxially, prominent abaxially, secondary venation brochidodromous, 16–20 pairs, arching, sunken adaxially, prominent abaxially, tertiary venation distinct on both sides, petioles green, straight, 13–15 mm long, 4.0– 4.5 mm in diameter, glabrous. Flowers solitary in leaf axils or 2–6 borne on a short bracteate shoot on old trunk, nodding; peduncle 2–4 mm long; pedicels 4–4.5 cm long, stout, thickened upwards, 1.7 mm wide at the proximal end, 5.5 mm wide at distal end, shiny or corky, hairy or glabrous, bearing 4 or 5 bracteoles; bracteoles ( sensu Sealy 1958) lanceolate, 15–18 mm long, 4–6 mm wide, abaxially densely covered with brown appressed tomentose hairs, adaxially glabrous, persistent; sepals 5, spirally arranged, distinctly differentiated from petals, ovate, 10–15 mm long, 6–10 mm wide, persistent, adaxially concave, abaxially densely covered with brown appressed tomentose hairs, adaxially glabrous, apex cuspidate; petals 10–11, spirally arranged, plain pale yellow, adaxially concave, widely ovate to orbicular, 15–18 mm long, 15–20 mm wide, abaxially hairy, adaxially glabrous, apex round, ciliate, margins revolute, basal 2–3 mm long united; stamens numerous, arranged in 3–4 whorls, filaments entirely yellow, glabrous, 14–18 mm long, basally united to form a 2–3 mm high fleshy tube; outer filaments basally united to the petals for 2–3 mm; ovary superior, diamond-shaped, 3–4 mm long, 4 mm in diameter, yellowish, densely hairy, 5–6-locular; locule 2-ovuled, styles 5 or 6, free to base, 20–22 mm long, pale yellow, hairy on basal 2/3–3/4, stigma indistinct. Capsule 5 or 6-carpellate, dehiscent, spherical, compressed, 2.5–3.5 cm high, 4.5–6.0 cm in diameter, distinctly 10–12-ridged, sutures between ridges distinctly deep. Seeds 10–12, laterally compressed, wedged-shaped, 2.5–3.0 cm long, 2.5–3.0 cm wide.

Additional specimens examined ( paratypes):— Vietnam. Dak Nong Province: Dak Glong District, Dak P’lao Commune , Ta Dung National Park , 11°50’57”N 108°00’52”E, 1520 m in elevation, 11 June 2021, Nguyen The Hien NTH-2021-02 ( SGN!; Herbarium of the Faculty of Agriculture and Forestry, Tay Nguyen University!) GoogleMaps ; same location, 21 September 2022, Nguyen The Hien NTH-2022-01 ( SGN!; Herbarium of the Faculty of Agriculture and Forestry, Tay Nguyen University!) GoogleMaps .

Phenology: — Flowering from March to April, and fruiting from June to October.

Distribution and habitat: — The new species is known from Ta Dung Nature Reserve in Dak Nong Province, Vietnam. It grows on wet, fertile soils along streams under the canopy of a tropical evergreen broad-leaved forest.

IUCN Red List Category: — The new species is known from a single population consisting of fewer than 20 mature individuals. No immediate threats to its survival have been identified; however, extensive botanical surveys conducted over the past five years across the 20,937.7-hectare Ta Dung National Park failed to locate any additional populations. The park experienced intensive logging in the past and is currently surrounded by large-scale agricultural development, leading to substantial habitat loss for the species. Its current Extent of Occurrence (EOO) and Area of Occupancy (AOO) are estimated to be less than 2 km ². Given these conditions, the species clearly meets the criteria for classification as Critically Endangered under any of the following IUCN criteria: B1 & B2a,b; C2a(i); or D, according to the Red List Categories and Criteria (Standards and Petitions Subcommittee, 2024).

Etymology: — The species is named after its type locality, Dak Plao Village, which was historically inhabited by the ethnic Ma community but was submerged due to the construction of Dong Nai 3 Hydropower Plant. The recommended common names are Dak Plao camellia (English) and Trà my Đăk Plao (Vietnamese).

Notes:— Camellia dakplaoensis is reasonably placed within section Piquetia based on its salient morphological characteristics, which include: large leaves, 2–6 nodding and pedicellate flowers borne on short shoots in the axils of the leaves, several bracts, stout and upward-thickened pedicel, 4–5 bracteoles, 5 persistent sepals, 10–11 petals, filaments free above their union with the petals, and a densely hairy ovary. Within the section, it is most morphologically similar to C. langbianensis ( Gagnepain 1939, Pham-Hoang 1991, Quach et al. 2021), though the two species can be distinguished as detailed in the diagnosis. Our field observations and personal communication with Dr. Quach confirm that the filaments of C. langbianensis are distinctly bi-colored, i.e., predominantly orange-red at the base (covering approximately the basal two-thirds to three-quarters), and yellow toward the apex ( Fig. 3 View FIGURE 3 ). This contrasts with the description in Quach et al. (2021), which reported entirely yellow filaments—a discrepancy attributable to the examination of withered specimens.

Camellia dakplaoensis also bears morphological similarities to C. proensis , as both species share a comparable overall appearance in terms of trees and flowers. Nonetheless, the latter can be differentiated by its larger leaves (33–35 × 7.5–8.5 cm versus 20–32 × 5–5.5 cm in C. dakplaoensis ); 2–3 bracteoles ( versus 4–5); hemispherical sepals with a rounded apex ( versus ovate sepals with a cuspidate apex); 10–11 greenish-yellowish petals ( versus petals 5–6, plain yellow); tomentose hairs on the basal half of the styles ( versus hairs covering the basal 2/3 to 3/4); and larger fruits measuring 4.0– 5.5 cm high, 8.5–10.0 cm in diameter, with slight five-ridges ( versus 2.5–3.5 cm high, 4.5–6.0 cm in diameter, with distinct 10–12 ridges). Morphological comparison between C. dakplaoensis and its close congeners is summarized in Table 1.