Bergera siamensis (Craib) F.J.Mou, 2023

Mou, Feng-Juan, Hu, Xiu, Ha, Bui Thu & Cuong, Nguyen Manh, 2023, Taxonomic revision of Bergera J. Koenig ex L. (Rutaceae) based on the molecular phylogeny and morphology, European Journal of Taxonomy 860, pp. 141-180 : 168-170

Bergera siamensis (Craib) F.J.Mou , comb. nov.

urn:lsid:ipni.org:names:77314672-1

Fig. 11

Murraya siamensis Craib , Bulletin of Miscellaneous Information 8: 340 ( Craib 1926). – Chalcas siamensis (Craib) Tanaka , Bulletin de la Société botanique de France 75 (4): 710 ( Tanaka 1928). – Type: THAILAND • Lampang, Mê Kat; alt. 250 m; 24 Apr. 1923; Winit 849; lectotype: K[K000382432] image!; isolectotype: BKF [SN055887] image!. Designated by Tanaka (1928).

Etymology

The specific epithet is derived from the type locality, Thailand (namely Siam).

Material examined

THAILAND • Nov. 1928; Put Nai 2123; TCD image!, L image ! • Nov. 1929; Put Nai 2440; TCD image ! • Lampang, Me Kart ; 24 Apr. 1923; Winit 849; K image!, BKF image ! • Saraburi, Pukae Botanical Garden , cultivated; 30 Mar. 1987; D.D. Soejarto et al. 5834; L image !.

Description

Small tree, up to 8 m tall. Trunk with fuscous or blackish bark having high ridges or deeply cracked; year-old twigs puberulous, then fuscous, with small lenticels; young twigs, rachis, petiolule, pedicel and sepal covered with short and curly pubescence. Leaves 15–30 cm long; leaflets 17–25, alternate or rarely subopposite, inequilateral, apex obtuse, subacuminate, 2–7 cm long, 1–2.7 cm broad, chartaceous, clearly dotted on the upper surface, above curly pubescent, very soon more or less glabrescent below, chiefly pubescent at the midrib, margin subentire or more or less obscurely crenulate; petiolule ca 2 mm long. Inflorescences are terminal, subcorymbose, small, 15 cm long, and with 10–15 flowers. Flower buds are small, oblong-ovoid, ca 5 mm long, without glandular dots; flowers greenish-white, aromatic; pedicels short, and ca 3–4 mm long; calyxes 5-lobed, ovate, lanceolate or deltoid, obtuse, 1.25 mm long, with long soft hairs, and persistent; petals 5, linear-oblanceolate, incurving-apiculate, 6.5 mm long, 1.75 mm wide, glabrous, thickened at the middle, and imbricate. Stamens are 10, alternate ones longer, filaments 4–5 mm long, narrowed toward the apex, the lower half slightly broader but scarcely complanate, anthers ca 1 mm long, and papillate. Disks are fleshy, glabrous, and slightly shorter than calyx. Ovaries are slightly oblong, cylindric, notched, glabrous, and shortly stipitate; styles cylindric, 3–5 mm long, articulated at the base, and glabrous; stigmas capitate. Fruits are black, large, up to 2 cm diam., somewhat 4-angled, with shallow depressions between slightly protuberant locules after drying. The species is described based merely on Swingle & Reece (1967) and some images of specimens images.

Phenology

Flowering between March and April, while fruiting from May to August

Distribution and habitat

The species is only found in Thailand (Lampang) in forestry between alt. 50 and 250 m.

Remarks

Although a few researchers reduced Bergera siamensis (syn. Murraya siamensis ) to a synonym of Bergera koenigii ( Esser 2021; Govaerts et al. 2021), it is an independent species based on both phylogenetic relationship and morphology. Although this species Bergera siamensis is closely allied with B. koenigii based on some morphological characteristics, the dots on the petals are nearly indistinct, filaments are less subulate, petals much narrower, and fruit much larger and 4-grooved; the pubescence of the plant is more pronounced than B. koenigii , and sometimes the whole plant is covered with white curved hairs. Many volatile oil glands were seen in its leaves ( Inpuron et al. 2013). It has a specific volatile smell and the crushed leaves are aromatic. In Thai folkloric medicine, it has been used for the treatment of blurred vision (eye sores), snake-poison and tuberculosis ( Likhitwitayawuid et al. 1999).

Figures

Fig. 11. Branches, leaves, flowers and fruits of Bergera siamensis (Craib) F.J.Mou comb. nov. A. Winit 849, K000382432 (holotype: the Kew Herbarium, K). B. SN055887 (isotype: Bangkok Forest Herbarium, BKF). C. D.D. Soejarto et al. 5834, L.2127107 (National Herbarium Nederland, Leiden University branch, L). D. Put Nai 2440, TCD0013457 (Trinity College Dublin Herbarium, TCD).