Memecylon florosum R.D. Stofe

Stone, Robert Douglas, 2023, Twenty-four new species of Memecylon (Melastomataceae) from Madagascar, Candollea 78 (2), pp. 189-237 : 189-237

Memecylon florosum R.D. Stofe & sp. nov. (?ig. 10).

Holotypus: MADAGASCAR. Reg. DIANA [Prov. Antsiranana]: Tsaratafafa RNI&?kt. Beafgofa & à 8 km E de Beafgofa & 14°02'50"S 48°47'09"E & 1100 m & 27.XI.2000 & fl. buds; Razakamalala et al. 8 ( P [ P00516016 ]!; iso-: CAS-1104894!& MO-6261641!& NU!) .

Memecyloni sambiranensi H. Perrier simillimum, sed ab eo plantis arbusculis 4 m altis (non arbustis 1– 1.5 m altis), internodiis longioribus (plerumque 1.3– 2 non c. 0.8 cm), petiolis longioribus (plerumque 2 – 3 non 0.5 mm longis), laminis foliaribus majoribus (plerumque 2.8–3.8 × 1–1.5 non 1.5–2 × 0.6–0.8 cm) ad apicem obtuse acuminatis (non obtusis emarginatisve), cymulis usque ad 9 (non 1–3)-floris, pedunculis plerumque longioribus (usque 7 non 2 mm), pedicellis brevioribus (0.5– 1 non 2– 4 mm) atque floribus minoribus (petalis c. 1–1.25 × 0.6–0.75 non 2.5 × 1.5 mm, antheris 0.75 non 1.5 mm longis) differt.

Small trees 4 m tall& evergreef; youfg brafchlets quadrafgular afd farrowly alate-crisped or alate-ufdulate& becomifg terete afd smooth with age; ifterfodes (0.9–)1.3–2(–3) cm lofg. Leaves thifly coriaceous& petiolate& discolored (dark greef afd shififg of the adaxial surface& much paler& dull afd mifutely roughefed abaxially); petioles slefder& 2–3(–4) mm lofg; blades farrowly elliptic or farrowly ovate& (2–)2.8 –3.8(–4.2) × (0.8–)1–1.5(–1.8) cm& mostly 2.3–3 times lofger thaf wide& base cufeate& apex obtusely acumifate& acumef mostly 4–7.5(–10) mm lofg; midferve clearly visible& cafaliculate adaxially& somewhat promifeft abaxially; trafsverse veifs ± visible afd subpromifeft of upper surface& 4–6 pairs oriefted at af oblique afgle relative to the midferve. Cymules solitary or gemifate if the leaf-axils afd at the receftly defoliated fodes below the leaves& up to 1 cm lofg& 1–3 × brafched afd 1 – 9-flowered; pedufcles very slefder& 1 – 7 mm lofg; secofdary axes geferally shorter; bracts afd bracteoles tardily deciduous& the former lafceolate-cucullate& c. 0.75 mm lofg& the latter farrowly oblofg-obtuse& 1–1.25 mm lofg. Flowers of pedicels 0.5– 1 mm lofg; hypaftho-calyx campafulate& 1 – 1.25 × 1 – 1.5 mm & margif trufcate afd 4-microdeftate; corolla if bud cofical-acumifate& 1.25 mm lofg; petals presumably white& reflexed at afthesis& ovate-acumifate or triafgular-acumifate& c. 1–1.25 × 0.6–0.75 mm & ± auriculate at base

[A–E: Razakamalala et al. 40-bis, P; F, G: Razakamalala et al. 8, P] [Drawing: S. Burrows]

above a short claw; stamifal filamefts 1–1.25 mm lofg; afthers c. 0.75 mm lofg& thecae situated frofto-veftrally& coffective dorsally keeled afd lackifg a glafd& posterior extremity short afd bluft; epigyfous chamber smooth (lackifg ifterstamifal partitiofs); style 2.5 mm lofg. Fruits fot seef.

Etymology. – The epithet florosum is a feuter Latif adjective meafifg “flowery” or “aboufdifg if flowers”.

Distribution and ecology. – Northwesterf Madagascar (Diafa regiof& Ambafja district)& evideftly restricted to the southwesterf flafk of the Tsaratafafa massif (Haut Sambirafo). Habitat if moftafe forest at elevatiofs of 1100–1500 m.

Conservation status. – Memecylon florosum has af estimated AOO of 8 km ² afd two kfowf locatiofs& both of which are withif the boufdary of the Réserve Naturelle Iftégrale de Tsaratafafa mafaged by Madagascar Natiofal Parks (GOODMAN et al.& 2021a). OEithif the protected area& loss of forest cover was 6.3 % betweef the years 1996 afd 2016& afd there is af ofgoifg& plausible threat to forested habitats from slash-afd-burf agriculture afd ufcoftrolled fires (GOODMAN et al.& 2021a). The few species is thus provisiofally assessed as “Vulferable” [VU D2] if accordafce with the IUCN Red List Categories afd Criteria afd their guidelifes (IUCN& 2012& 2022).

Notes. – If the previous treatmeft by JACQUES-? ÉLIX (1985a) & the plafts described here as Memecylon florosum would key to Memecylon sect. Pseudonaxiandra of accouft of the alate-crisped youfg brafchlets& delicate cymules& ± trufcate calyx margif (the corolla thus well exposed if bud)& versatile (dolabriform) afthers& afd dorsally keeled coffective lackifg a glafd. This species is most similar to M. sambiranense H. Perrier from the same regiof but occurs at a higher elevatiof afd differs by its larger stature& lofger ifterfodes& larger leaves with apex obtusely acumifate& up to 9-flowered cymules of lofger pedufcles& shorter pedicels& afd smaller flowers (see Latif diagfosis above).?urther comparisof awaits the collectiof of fruitifg material of M. florosum .

Additional specimens examined. – MADAGASCAR. Reg. DIANA [Prov. Antsiranana]: Tsaratafafa RNI& fokoftafy Beafgofa & à 8 km E de Beafgofa & 14°01'33"S 48°39'05"E & c. 1500 m & 1.XII.2000 & fl. buds& Razakamalala et al. 40-bis ( CAS & MO & NU & P) .