Medusanthera gracilis (King) Sleumer

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Utteridge, T.M.A. Kew Bull (2011) 66: 49. https://doi.org/10.1007/s12225-011-9266-z

Morphology General Habit

Tree 5 – 10.7 m high, girth 4 – 15 cm

Morphology General Indumentum

Indumentum of simple appressed hairs, translucent, colourless or pale yellow to pale ginger-brown, 0.15 – 0.35 mm long (see description of specific structures for distribution)

Morphology Branches

Branches 1 – 2 mm in diameter, densely hairy soon glabrous, drying dull olive-brown

Morphology Leaves

Leaves membranaceous to chartaceous, narrowly elliptic, (3.3 –) 6.5 – 10 (– 15.3) × (0.8 –) 1.7 – 3.6 (– 5) cm, apex acute to attenuate, base cuneate; ad- and abaxial lamina sparsely hairy soon glabrous, lamina drying dark olive-green adaxially, dull-green abaxially; midrib adaxially sulcate and sparsely hairy when young, soon glabrous, abaxially prominent and hairy when young soon glabrous; secondary veins brochidodromus, not enclosed by secondary arches, 4 – 6 (– 8) pairs, glabrous, somewhat prominent ad- and abaxially; tertiary veins inconspicuous; petioles 4.5 – 10.5 (– 15) mm long, densely hairy when young soon glabrous

Morphology Reproductive morphology Inflorescences

Staminate inflorescences axillary in the terminal axils of the branches, umbellate with ultimate branches terminating in a cyme or irregular cyme, primary axis 10.9 – 33 mm long with 4 first order branches at the apex, branched to 3 orders, glabrous to hairy, becoming densely hairy especially toward the most distal branching points; pedicels 0.5 – 0.9 mm long, hairy or sparsely hairy Pistillate inflorescences and flowers as staminate except inflorescence primary axis to 50 (– 81) mm long, staminodes with sterile anthers 0.2 mm long, filaments 2 – 2.4 mm long, glabrous; ovary cylindrical, 2.3 – 2.7 × 0.6 – 1.2 mm, glabrous

Morphology Reproductive morphology Flowers

Staminate flowers pentamerous, calyx gamosepalous, crateriform, 0.5 – 0.7 mm long, shallowly 5-lobed, glabrous; petals white, cream coloured or light yellowish green white, narrowly oblong, 2.4 – 3.4 mm long; stamens with anthers 0.3 – 0.5 mm long, filaments very narrowly oblong, 1.6 – 2.4 mm long, hairy to densely hairy with linear, clavate membranous hairs, 1.5 – 2 mm long on the ad- and abaxial surface from halfway along the filament to immediately below the anthers; pistillode ovoid, 1.1 – 1.3 × 0.5 – 0.7 mm, glabrous

Morphology Reproductive morphology Fruits

Fruits narrowly elliptic to narrowly oblong, truncate at the base, apex cuneate, glabrous; when dry putamen flat or curved, 12.2 – 19.3 × 5.2 – 6.6 mm and 2.4 – 4.1 mm thick (dimensions include drupe and appendage), putamen with a central ridge with 1 – 3 smaller ridges on either side on the convex side, pulviniform appendage oblong, covering the central area of the concave surface; when fresh drupe fruits very glossy, green, pulviniform appendage fleshy, yellowish-green or white.

Distribution

Distributed in western Malesia in the following countries: Malaysia: restricted to, but throughout, the peninsula; Indonesia: restricted to northern Sumatra; Thailand: currently known from a single collection from southern part of Yala Province.

Ecology

Primary and disturbed forest, hill forest and bamboo forest (Malaysia); evergreen forest (Thailand); (30 –) 120 – 1400 m.

Conservation

Least Concern (LC). Medusanthera gracilis is known from 49 collections from 31 localities throughout its distributional range from diverse habitats; the EOO (182,339 km2) suggests a rating of LC. Habitat conversion in Peninsular Malaysia and Sumatra, however, is occurring at a rapid pace (see e.g., Aiken & Leigh 1992; Soh et al. 2006), and areas of natural habitat are becoming fragmented. Examination of the region using satellite imagery shows that many of the collection points are still covered with some habitat (although the quality and type of habitat is unknown) and, because of the wide distribution and broad habitat preferences of this species, a rating of LC is recommended at this time. Further fieldwork in the region may show, however, that some of the localities should not be used for calculating the IUCN rating, such as those close to cities or towns.

Vernacular

Kaju si gorga (Asahan); sampin kris (Kelantan) (Sleumer 1971).

Note

Medusanthera gracilis can be confused with species of Gomphandra in Peninsular Malaysia especially when fruits are not available. However, Gomphandra species can be distinguished from M. gracilis by their exserted stamens (M. gracilis has inserted stamens), the inflorescence arrangement (irregularly branching to 1 or 2 orders only), and the erect hairs — often ginger in colour — which are persistent on the leaves, branches and inflorescences (M. gracilis is glabrescent). Sleumer’s reference (1969, 1971) to “Gomphandra lanceolata (Mast.) King var. angustifolia King apud Ridl. Fl. Malay. Peninsula 1: 429 (1922) pro parte” and placement of that name as a synonym of M. gracilis, is due to Sleumer’s assumption that some of the specimens cited by Ridley as G. lanceolata (Mast.) King var. angustifolia King are actually M. gracilis. However, examination of the K material places them as Ridley initially determined them, i.e., outside of M. gracilis, as species of Gomphandra. I believe that, in this case, all of Ridley’s determinations are correct, hence the removal of the reference to G. lanceolata var. angustifolia as a synonym of M. gracilis in the taxonomy above. This species was not included in Howard’s revision of the genus (Howard 1943b). Medusanthera gracilis is a distinctive species on account of its habit (a small tree, recorded to 10.7 m), the leaf morphology (lamina membranaceous to chartaceous, narrowly elliptic, relatively small usually 6.5 – 10 × 1.7 – 3.6 cm), and the umbellate inflorescence which is initially axillary in the terminal axils of the branches with 4 first order branches at the apex of the primary axis. However, leaf size can be very variable within this species; M. gracilis var. gracillima Ridl. was described because of the very small leaves, but even in a single collection, see for example Ogata KEP 110213, leaf size can vary between the smallest and largest measurements recorded. The only other species of Medusanthera in western Malesia (Peninsular Malaysia and Sumatra) and Thailand is M. malayana Utteridge (see below for description of this new species), but M. gracilis is unlikely to be confused with that species because of the chartaceous, narrowly elliptic leaves which dry green (M. malayana has coriaceous, narrowly oblong leaves which dry brown), and the umbellate inflorescence (racemose in M. malayana).