Melastoma L.

Key to the species of Melastoma in Laos 1. Hypanthium with penicillate or stellate emergences ......................................................................... 2 – Hypanthium with simple scales, bristles, or hairs ............................................................................. 4 2. Hypanthium 3–6 mm long; petals 6–8 mm long .......................................... M. orientale Guillaumin – Hypanthium 6–13 mm long; petals 15–30 mm long ......................................................................... 3 3. Young twigs (sub)quadrangular; lamina ovate to elliptic; stalk of emergences on hypanthium 3–5 mm long.............................................................................................. M. saigonense (Kuntze) Merr. – Young twigs terete; lamina ovate-lanceolate to lanceolate; stalk of emergences on hypanthium 1–1.5 mm long................................................................ M. calcicolum Souvann. & Tagane sp. nov. 4. Fruits apically dehiscent dry capsule................................................................................................. 5 – Fruits longitudinally or transversely dehiscent fleshy capsule .......................................................... 6 5. Young branches terete.................................... M. souladethianum Souvann. & Nob.Tanaka sp. nov. – Young branches quadrangular....................................... M. pellegrinianum (H.Boissieu) Karst.Mey. 6. Hypanthium covered with spreading bristles ................................................... M. sanguineum Sims – Hypanthium covered with appressed scales ...................................................................................... 7 7. Branches covered with scales ........................................................................... M. malabathricum L. – Branches pilose ............................. M. malabathricum subsp. normale (D.Don) Karst.Mey.