Garcinia section Discostigma (Haask.) Hook.f., Gen. Pl. [Benth. & Hook.f.] 1: 174 (1862). Clade 4

Gaudeul, Myriam, Sweeney, Patrick & Munzinger, Jerome, 2024, An updated infrageneric classification of the pantropical species-rich genus Garcinia L. (Clusiaceae) and some insights into the systematics of New Caledonian species, based on molecular and morphological evidence, PhytoKeys 239, pp. 73-105 : 73

5. Garcinia section Discostigma (Haask.) Hook.f., Gen. Pl. [Benth. & Hook.f.] 1: 174 (1862). Clade 4

Figs 2 , 3

Basionym.

Discostigma Hassk., Flora 25(2, Beibl.): 33 (1842).

Type.

Discostigma rostratum Hassk., Flora 25(2, Beibl.): 33 (1842) [≡ Garcinia rostrata (Hassk.) Miq., Ann. Mus. Bot. Lugduno-Batavi 1(7): 209 (1864)].

Distinguishing sectional characters.

Flowers with four sepals and petals. Staminate flowers with a pistillode, stamens arranged into four fascicles that are distally covered with sessile to subsessile, two-thecous anthers. Ovaries bilocular (or unilocular; four-locular in G. yunnanensis ), stigmas unlobed and smooth. Fruits with a smooth surface and capped with a conspicuous discoid stigma, sepals caducous in fruits. Inflorescences terminal or axillary with few to many flowers. Indomalaya, tropical Australasia, and Oceania.

Sweeney (2008) noted that there were two groups of species placed into Garcinia Discotigma by Jones (1980) that differed from typical members of the section by their androecial morphology. One group of species differs by having their stamens fused to the petals and includes G. balansae , G. lanessanii Pierre, G. terpnophylla Thwaites, and G. warrenii F.Muell. The position of G. warrenii in the trees presented here and in Sweeney (2008) suggests that some of these species may be better placed within Garcinia Macrostigma (clade 9); however, our molecular analyses find strong support for placement of G. balansae within Discostigma . The second group of species is restricted to New Guinea, the Philippines, and Taiwan and includes G. dives Pierre, G. hunsteinii Lauterb., G. linii C. E. Chang, G. luzoniensis Merrill, and G. palawanensis Elmer ( Jones 1980). This latter group is reported to have peltate anthers, like species of section Hebradendron (sensu Jones 1980); however, Jones (1980) placed them into Garcinia Discostigma because they share the same stamen arrangement and pollen apertures as typical members of the section. Species representing the G. dives group have not yet been included in molecular phylogenetic analyses. Garcinia anomala was placed into Section Hebradendron Garcinia by Jones (1980), but excluded from that section by Nazre et al. (2018), due to its possession of axillary inflorescences in thyrses and stamens being united into an unlobed annular mass. Fruit characters suggest that this species belongs to Section Discostigma ; however, the stamens are arranged into a ring.

In our ITS phylogeny, two species not treated by Jones (1980), G. archboldiana A.C. Sm. and G. engleriana A.C.Sm., are weakly supported as sister to Garcinia Discostigma ; however, in the chloroplast phylogeny these two species are shown as sister to a larger clade comprised of sections Brindonia , Garcinia , Hebradendron , and Macrostigma . The staminate flowers of G. archboldiana and G. engleriana lack pistillodes and they have deeply branched fascicles with numerous subpeltate anthers ( Smith 1941). We leave these species unplaced. Future molecular and morphological work may warrant the placement of these species into their own section.

Species.

Garcinia apetala Pierre; G. balansae Pierre; G. balica Miq.; G. binnendijkii Pierre; G. boerlagii Pierre; G. brevirostris Scheff.; G. cadelliana King; G. calophylla Pierre; G. calophyllifolia Ridl.; G. caudiculata Ridl.; G. cordata Merr.; G. cuneifolia Pierre; G. cuspidata King; G. diversifolia King; G. dives Pierre; G. dryobalanoides Pierre; G. enthaematoeides Lauterb.; G. gitingensis Elmer; G. grandifolia (Choisy) Pierre; G. hasskarlii Pierre; G. havilandii Stapf; G. holttumii Ridl.; G. hunsteinii Lauterb.; G. jensenii W.E.Cooper; G. keenania Pierre; G. kwangsiensis Merr. ex F.N.Wei; G. lanceola Ridl.; G. lancilimba C.Y.Wu ex Y.H.Li; G. lanessanii Pierre; G. linearis Pierre; G. linii C.E. Chang; G. luzoniensis Merr.; G. memecyloides Ridl.; G. merguensis Wight; G. microphylla Merr.; G. minimiflora Ridl.; G. minutiflora Ridl.; G. monantha Ridl.; G. multiflora Champ. ex Benth.; G. murtonii Whitmore; G. myrtifolia A.C.Sm.; G. novoguineensis Vesque; G. picrorhiza Miq.; G. rostrata (Hassk.) Miq.; G. salakensis Pierre; G. sampitana Diels; G. santisukiana Ngerns. & Suddee; G. sarawhensis Pierre; G. scaphopetala B.L.Burtt; G. tauensis Lauterb.; G. terpnophylla Thwaites; G. tetralata C.Y.Wu ex Y.H.Li; G. travancorica Bedd.; G. treubii Pierre; G. umbonata Lauterb.; G. versteegii Lauterb.; G. vitiensis (A. Gray) Seem.; G. wollastonii Ridl.; G. zichii W.E.Cooper.

Figures

Figure 2. Molecular phylogeny of Garcinia L. based on ITS sequences and Bayesian inference. Posterior probabilities (PP) and bootstrap support values (BS), obtained respectively by the Bayesian inference and Maximum Likelihood (ML) analysis, are indicated at each node of the cladogram. Nodes were collapsed when PP <0.50. The lineages / sections discussed in the text are highlighted, and species names appear in colors depending on their native distribution areas: light blue, Central and South America; light green, Tropical Africa; dark green, Madagascar and Western Indian Ocean islands; grey, Southeast Asia; purple, Australia; orange, New Guinea; red, New Caledonia; dark blue, Southwest Pacific islands. Distribution information was taken from the Plants of the World Online website (POWO 2023; also see the table of vouchers). A few species occur in several regions, and the color of the main (largest) geographic region was used. Accessions in bold were newly sequenced in this study.

Figure 3. Molecular phylogeny of Garcinia L. based on a combined chloroplast DNA dataset and Bayesian inference. Posterior probabilities (PP) and bootstrap support values (BS), obtained respectively by the Bayesian inference and Maximum Likelihood (ML) analysis, are indicated at each node of the cladogram. Nodes were collapsed when PP <0.50. The lineages / sections discussed in the text are highlighted, and species names appear in colors depending on their native distribution areas: light green, Tropical Africa; dark green, Madagascar and Western Indian Ocean islands; grey, Southeast Asia; purple, Australia; orange, New Guinea; red, New Caledonia; dark blue, Southwest Pacific islands. Distribution information was taken from the Plants of the World Online website (POWO 2023; also see the table of vouchers). A few species occur in several regions, and the color of the main (largest) region was used. All accessions were newly sequenced in this study.