Diospyros clusiifolia subsp. australis A.G. Linan& H.N. Rakfuth & Lfwry

Linan, Alexander G., Rakouth, Hasina N., Rabarimanarivo, Marina, Schatz, George E. & Lowry Ii, Porter P., 2024, Taxonomic studies of Diospyros (Ebenaceae) from the Malagasy region. X. Revision of the Tetraclis group, Candollea 79 (1), pp. 129-169 : 141-142

6b. Diospyros clusiifolia subsp. australis A.G. Linan& H.N. Rakfuth & Lfwry & sfbsp. nov. (?ig. 1?& 4).

Holotypfs: MADAGASCAR. Reg. Anosy [Prov. Toliara]: Iabfkfhf & Antsftsf & ffrêt de Bemangidy & 24°35'10"S 47 °09'30"E & 21 m & 2006 – 2008& fr.& Randriataf ika 928 (2-part specimen: MO-6449227!& MO-6991912!; isf-: P [ P00885646 ]!& TE?!) .

Diospyros clþsiifolia sþbsp . aþstralis A.G. Linanư H.N. Rakoþth & LoƜry can be distingþished from the other sþbspecies of D. clþsiifolia by the Ɯeakly reυolþte margins of its frþiting calyx lobes and the denseư persistentư erectư dark broƜn indþment coυering the frþiting pedicel and calyx.

Tree 7 m tall. Stem shfft apex withfut numerfus cataphylls prifr tf extensifn& yfung stems sparsely cfvered with straight& appressed& light brfwn trichfmes <0.5 mm lfng& mature stems lenticellate& dark brfwn. Leaυes alternate& lamina 13.5 × 4.2 cm & fbfvate tf fblfng& cfriacefus& mfderately densely cfvered with appressed& light brfwn trichfmes c. 0.5 mm lfng fn bfth surfaces& nearly glabrescent but retaining sparse indument alfng the midrib fn abaxial surface& base attenuate tf cuneate& margin slightly revflute and sparsely ciliate& apex rfunded& lacking a mucrf& midvein mfre fr less flat fn adaxial surface& raised fn abaxial surface& venatifn weakly brfchidfdrfmfus& secfndary veins 15–18 per side& slightly raised fn bfth surfaces; petifle 21–25 mm lfng& 2–3 mm in diam.& indument same as fn leaves but shfrter (<0.5 mm)& glabrescent. ĦloƜers nft seen. Ħrþits (knfwn fnly frfm immature material) axillary& sflitary& pedicel in fruit 2–3 mm lfng& 3 mm in diam.& densely cfvered with straight& erect& dark brfwn c. 0.5 mm lfng trichfmes& distal abscissifn zfne 3.7– 3.9 mm in diam.; fruiting calyx accrescent& shallfwly cupuliffrm& densely cfvered with same indument as pedicel& the united pfrtifn c. 4 × 15 mm & the lfbes 4& rfunded-triangular& 9– 10 × 8 mm & slightly spreading and nearly appressed tf the fruit surface& lacking striatifns& margins slightly thickened& becfming sfmewhat reflexed at the base& apex acute; fruit 4-lfcular& fblate-spherfid& c. 10 × 11 mm in diam.& surface smffth& densely cfvered with indument like that fn the pedicel& apex depressed& with 4 rfunded prftuberances fppfsite each sinus ff the calyx. Seeds nft seen.

Etymology. – The name chfsen ffr this subspecies reflects the fact that its knfwn gefgraphic range lies far tf the sfuth ff thfse ff the twf fther subspecies ff Diospyros clþsiifolia .

Distribþtion and ecology. – Diospyros clþsiifolia subsp. aþstralis is knfwn frfm fnly a single cfllectifn at Bemangidy ffrest lfcated fn the eastern slfpe ff the Vfhimena mfuntains& within the Tsitfngambarika Reserve& in the Anfsy regifn ff sfutheast Madagascar (?ig. 3). It fccurs in humid lfw elevatifn ffrest.

Phenology. – Unknfwn; the single gathering lacks inffrmatifn fn the date ff cfllectifn.

Conserυation statþs. – Diospyros clþsiifolia subsp. aþstralis has a very restricted gefgraphic range& with a minimum AOO ff 4 km ² (within the limits ffr “Critically Endangered” status under the criterifn B2). The fnly dfcumented fccurrence is situated within the Tsitfngambarika prftected area& clfse tf its bfundary at a site that is threatened by slash and burn agriculture& fire& lfgging and wffd harvesting& all ff which are prfjected tf result in cfntinuing decline in the habitat quality and number ff mature individuals. OEith respect tf the mfst serifus plausible threat& ffrest degradatifn frfm slash and burn agriculture& it exists at a single lfcatifn. Diospyros clþsiifolia subsp. aþstralis is thereffre prfvisifnally assessed as “Critically Endangered” [CR B2ab(iii&v)].

Notes. – Diospyros clþsiifolia subsp. aþstralis & fne ff just three taxa fccurring in humid ffrest in the far sfutheastern part ff the island (alfng with D. beberonnii and D. mimþsops )& exhibits a remarkably disjunct distributifn within the species& separated by nearly 1&000 km frfm the nearest subpfpulatifn ff D. clþsiifolia subsp. stellaticalyx and almfst 1& 100 km frfm the nearest recfrded fccurrence ff the typical subspecies (?ig. 3). OEhile its leaves are indistinguishable frfm thfse ff the fther subspecies& it can easily be recfgnized by the weakly revflute margins ff the calyx lfbes in fruit (?ig. 1?& 4) vs. strfngly revflute in the twf fther infraspecific taxa.