Revised treatment of Memecylon section Buxifolia (Melastomataceae) in Madagascar Author Stone, Robert Douglas text Candollea 2022 2022-09-14 77 2 173 191 http://dx.doi.org/10.15553/c2022v772a5 journal article 10.15553/c2022v772a5 2235-3658 7616620 2. Memecylon amplifolium R.D. Stone in Adansonia, sér. 3, 28: 350. 2006. Holotypus : MADAGASCAR . Reg. DIANA [Prov. Antsiranana ]: camp 2 km before Anjahakely , 12°53'43"S 49°18'27 "E , c. 550 m , 27.V.1997 , fr., Andrianantoanina & Bezara 1065 ( CAS-973439 !; iso-: G [G00424853]!, K [K000880895]!, MO-6260009!, P [P00257993]!, TAN!) . Shrubs or small trees to 5 m high; young branchlets terete (not quadrangular), thickened at the nodes; successive nodes alternately bearing normal leaves and floral bracts (these rapidly deciduous and not seen); internodes between normal leaves (2.1–)2.6– 3.6(–4.1) cm long. Leaves coriaceous, dark green and shining on the upper surface, paler and dull on the lower, drying brownish and rugose on both surfaces; petiole distinct but very short, robust, flattened on the adaxial side; blades obovate to broadly elliptic, 5.5–6.5(–7) × (2.1–)2.5–3.3 (–3.9) cm, cuneate at base, broadly short-acuminate and acute at apex (the acumen up to 5 mm long); midnerve impressed on the upper surface, ± prominent on the lower (especially toward the base); one pair of lateral nerves faintly visible on both surfaces, the course curvilinear and 3.5–5 mm from the margin in the basal half of the blade; transverse veins ± obscure. Cymules c. 1 cm long, generally solitary at the nodes below the current leaves or the “aphyllous” nodes alternating with those bearing normal leaves; peduncles 1– 3 mm long, secondary axes 1–3(–4) mm long; bracts deciduous. Flowers not seen. Fruits ellipsoid, 7–9 × 5.5–6 mm in diam., on pedicels 1.5–2 mm long; calycinal crown spreading, 1 mm long, the margin thin and 4-emarginate between the ± truncate lobes. Distribution and ecology . – Northern Madagascar (DIANA region), evidently restricted to the Ankarana plateau and the Andrafiamena mountain chain. Habitat in dry, semi-deciduous forest (always on limestone?), at elevations c. 230– 550 m . Conservation status . – Memecylon amplifolium is known from two locations with an estimated AOO of 8 km ². The type locality near Anjahakely is in the northern part of the Paysage Harmonieux Protégé d’Andrafiamena Andavakoera (73,710 ha) currently managed by Association F anamby. However, between the years 1996 and 2016, this area sustained a major loss of 4,865 ha (28 %) of total forest cover (GOODMAN et al., 2018), and M. amplifolium could not be found during field-work there in F ebruary 2008, suggesting that the species may be locally extirpated (R.D. Stone, pers. obs.). Ongoing anthropogenic pressures include slash-and-burn agriculture (especially around mineral exploitation sites), destruction of forested habitat related to illegal gold mining and sapphire extraction, uncontrolled fires, exploitation of hardwoods, and collection of non-woody forest products (GOODMAN et al., 2018). The second locality near Ambondromifehy has low precision but may be in the Réserve Spéciale d’Ankarana. Based on its few known locations, limited AOO and the apparent threats, M. amplifolium is provisionally assessed as “Endangered” [EN A2(c)+B2ab(iii)] in accordance with the IUCN Red List Categories and Criteria (IUCN, 2012). The possibility exists that this species is already extinct, although there are some recent examples of so-called “forest phantoms” being rediscovered after not being seen for many years (SCHATZ et al., 1998; STONE, 2012). Notes . – The leaves of Memecylon amplifolium are distinctly larger than those of M. buxifolium (= M. perrieri Danguy ); also characteristic are its terete young branchlets (vs. quadrangular). At the locality near Ambondromifehy, it has been found growing together with M. buxifolium (based on Service Forestier 24558 and 24729 ). Another collection, Perrier de la Bâthie 18761 from Ambohipiraka mountain, was originally placed in M. amplifolium (STONE, 2006b) but corresponds to M. ambilobense (see above). Additional specimen examined . – MADAGASCAR . Reg. DIANA [Prov. Antsiranana ]: calcaires lapiazés de l’Ankarana , près d’Ambondromifehy , 28.IV.1966 , Service Forestier 24729 (P, TE F) .