Lasianthus Jack (1823:125)

Napiroon, Tiwtawat, Chayamarit, Kongkanda, Dawson, Sally, Till, Walter & Balslev, Henrik, 2020, A synopsis of Lasianthus (Lasiantheae, Rubiaceae) in Thailand and two additional new species, Phytotaxa 439 (1), pp. 1-38 : 3

Lasianthus Jack (1823:125) , nom. cons. Type: — Lasianthus cyanocarpus Jack (1823: 125) , typ. cons.

= Dasus Loureiro (1790:141) , nom. rej. Type: ― D. verticillata Loureiro (1790: 141) . ≡ Lasianthus verticillatus (Loureiro) Merrill (1935:

372). = Mephitidia Reinwardt ex Blume (1823:51) . Type: ― M. hexandra Blume (1823: 51) ≡ Lasianthus hexandrus (Blume) Blume = Litosanthes Blume (1823:22) ; (1826–1827:994). Type: ― L. biflora Blume (1823: 22) . = Santia Wight & Arnott (1834:422) , nom. illeg., non Santia Savi (1799:479) . Type: ― S. venulosa Wight & Arnott (1834: 422) . ≡

Lasianthus venulosus (Wight & Arnott) Wight (1846: 508) .

Shrubs or rarely treelets, up to 5 m tall; branches and branchlets terete, glabrous or hairy. Stipules interpetiolar, usually persistent, inconspicuous, triangular, lanceolate, ovate or oblong; apex acute or obtuse. Leaves opposite, apex acuminate, acute or cuspidate, base acute, rounded or cordate to rarely oblique, usually thinly coriaceous or chartaceous; midrib flat, depressed or slightly prominent above, usually prominent beneath; lateral veins (5‒) 6 (‒18) pairs, generally prominent beneath, ascending at an angle of more than 45°, curved to the margin or joining veins above at margin; veinlets parallel or reticulate. Inflorescences cymose, axillary, rarely supra-axillary, opposite, sessile, several-flowered; peduncles conspicuous or compressed, stout to extremely congested; bracts linear, lanceolate to narrowly lanceolate or rarely leaf-like, (3–) 5 (‒15) mm, persistent or absent. Flowers small; sessile or pedicels up to 5 mm long. Calyx campanulate or obconical; with 3–6 teeth or lobes, rarely with cupular limb truncate at apex, persistent on fruits. Corolla white, funnel- or salver-shaped, 2–2.5 cm long, glabrous or hairy on the outside; throat usually villous or pubescent inside; lobes 4–6, valvate or imbricate in bud. Stamens (4‒) 5 (‒6), inserted in throat of corolla; filaments short; anthers linear or oblong, innate, included or exserted. Ovary 3–10-loculed, ovule 1 in each locule, basal, erect; style filiform; stigma lobed. Fruits drupaceous, small, pulpy, blue, purple, or rarely white and orange-red or black, globose, subglobose or ovoid, glabrous or with indumentum, rounded or ridged; pyrenes 2–10, fresh fruits smooth, warty or sulcate, usually triangular in transverse section.

A recent revision of the genus Lasianthus include about 180 species in tropical areas of the world. There are more than 160 species in tropical Asia, more than 130 species which have been revised taxonomically in various regions of Southeast Asia, 20 species in Africa, 1 species in Australia and 3 species in tropical America. In Thailand, a total of 57 species, one subspecies, and 11 varieties were reported by Zhu (2001, 2002).