Beguea tsaratananensis G.E. Schatz, Gereau & Lowry

George E. Schatz, Roy E. Gereau & Porter P. Lowry Ii, 2017, A revision of the endemic Malagasy genus Beguea (Sapindaceae), Candollea 72 (1), pp. 45-65 : 58-61

8. Beguea tsaratananensis G.E. Schatz, Gereau & Lowry , spec. nova

( Fig. 10 ).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA Region, Tsaratanana Massif , southern slopes , 14̊03’26’’S 48̊55’29’’E, 1622 m, 2.XI.2000, fl., Antilahimena 631 (holo-: MO-6641488 !; iso-: BM, G!, K!, L!, P [ P06168857 ]!, TAN!).

Haec species a congeneris caulibus petiolis et folii rhachide dense breviterque aureo-sericeis (petiolis rhachideque deinde glabrescentibus), foliolis in sicco complanatis marginibus non revolutis costa abaxialiter parce sericeis apice acutis acuminatisve atque sepalis glabris distinguitur.

Tree to 14 m tall, bole c. 19 cm in diam.; stems densely golden short sericeous. Petioles 2.3-6.6 cm, densely golden short sericeous, glabrescent. Leaves trifoliolate or with 4-11 subopposite to alternate leaflets; rachis 2.2-11.7 cm, not keeled, initially densely short golden sericeous, glabrescent; petiolule 2-9 mm, sparsely short golden sericeous, glabrescent; leaflet blade 3.8-12.5 × 1.7-3.9 cm, ovate to lanceolate, chartaceous, flat in pressed material, glabrous and slightly glossy and somewhat verrucose above, glabrous and dull below, base asymmetrical, cuneate to attenuate and decurrent along petiolule, margins flat, apex acute to acuminate, midvein raised and knife-like above, glabrous, raised below, sparsely short sericeous, secondary veins 12-17 per side, flat to slightly raised above, flat below, tertiary venation slightly raised above, flat below. Inflorescence axis 3-12 cm long, 0.9-1 mm in diam., unbranched, densely golden ferruginous strigulose; bracts minute, c. 0.2 mm, narrowly triangular; pedicels 0.5-1.5 mm, c. 0.2 mm in diam., densely golden ferruginous strigulose. Male flowers with a cupulate, 5- or 6-lobed calyx, the lobes c. 1.0 × 0.5 mm, triangular, glabrous; stamens usually 7 (rarely 6 or 8), filaments 1.8-4.5 mm, glabrous, anthers c. 1 × 0.5 mm, ellipsoid; disc 1.6 mm in diam., densely white granular-farinose; pistillode 0.6 mm tall, conical, densely ferruginous setaceous. Female flowers not seen. Fruit not seen.

Fig. 9. – Begueo golokensis G.E. Schatz & Lowry. A. Flowering branch; B. Leaflet (lower surface); C. Leaflet (upper surface); D. Portion of inflorescence axis with two flowers.

[Monjoto et ol. 454, P] [Drawing: R.L. Andriamiarisoa]

Conservation status. – Despite the very restricted AOO based upon two localities within the well-protected Tsaratanana Strict Nature Reserve ( Fig. 4 ), there appear to be no current threats, and thus B. tsaratananensis is assigned a status of “Least Concern” [LC] using the IUCN Red List criteria ( IUCN, 2012), with the caution that this status is highly dependent on continued effective protection.

Notes. – Beguea tsaratananensis is known only from two collections from the Tsaratanana massif ( Fig. 4 ). It can be recognized from other members of the genus by the short, dense, golden sericeous indument of the stems, young petioles and leaf rachises, the non-folded leaflets with flat margins and the midrib sparsely sericeous beneath, and the glabrous sepals of the male flowers. It can be distinguished from the morphologically similar B. vulgaris by its leaflets with flat (vs revolute) margins and glabrous (vs puberulous) sepals ( Fig. 11 ).

Paratypi. – MADAGASCAR. Prov. Antsiranana: DIANA Region, Tsaratanana RNI , Fokontany Beangona , à 8 km E de Beangona, Antsahamanara , 14̊02’50’’S 48̊47’09’’E, 1408 m, 29.XI.2000, fl., Razakamalala, Ratovoson & Antonjara 32 ( G, K, L, MO, P, TAN).

Figures

Fig. 4. – Geographic distribution of Begueo opetolo Capuron (circles), B. birkinshowii G. E. Schatz, Gereau & Lowry (stars), B. boreolis G. E. Schatz & Lowry (diamond), B. tsorotononensis G. E. Schatz, Gereau & Lowry (squares) and B. turkii G. E. Schatz, Gereau & Lowry (triangles), mapped on the bioclimatic zones of Madagascar (after CORNET, 1974; see SCHATZ, 2000).

Fig. 10. - Begueo tsorotononensis G. E. Schatz, Gereau & Lowry. A. Flowering branch; B. Portion of inflorescence axis; C. Detail of flower at anthesis. [Antilohimeno 631, MO] [Drawing: R. L. Andriamiarisoa]

Fig. 11. – Begueo turkii G. E. Schatz, Gereau & Lowry. A. Flowering branch; B. Portion of inflorescence axis; C. Detail of flower at anthesis; D. Infructescence axis with fruits; E. Seed. [A-C: Turk & Solo 192, MO; D: Rokotomolozo 492, MO] [Drawing: R. L. Andriamiarisoa]