Beguea australis 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 : 51-53

3. Beguea australis G.E. Schatz, Gereau & Lowry , spec. nova

( Fig. 5 ).

Typus: MADAGASCAR. Prov. Toliara: Anosy Region, RNI Andohahela , Parcelle 1 , Ambahibe , Isaka Ivondro , 24̊47’S 46̊50’E, 0-500 m, 10-27.IX.1993, fr., Randriamampionona 633 (holo-: MO-6641487!; iso-: BM!, C!, CAS!, E!, G [ G00341687 ]!, K!, L!, M!, NY!, P [ P00580343 ]!, PRE!, TAN!, UPS!, US!).

Haec species a congeneris foliolis ad apicem retusis usque profunde emarginatis atque fructu lignoso mesocarpio 3-4.7 mm crasso distinguitur.

Tree to 20 m tall, bole c. 20 cm in diam.; stems densely light reddish tan tomentose. Petioles 7.5-10 cm, densely light reddish tan tomentose. Leaves with 12-30 alternate to subopposite leaflets; rachis 18-21 cm, densely light reddish tan tomentulose, not keeled; petiolule 2-7 mm, densely light reddish tan tomentulose; leaflet blade 4.6-12.6 × 2.4-4.4 cm, elliptic to narrowly obovate, chartaceous to subcoriaceous, flat in pressed material, glabrous and somewhat glossy and verrucose above, initially reddish tomentulose below, glabrescent or indument persistent close to the midvein below, base asymmetrical, cuneate to attenuate and decurrent along petiolule, margins flat, apex retuse to deeply emarginate, the notch to 1 cm deep and often with straight sides (“v ”-notched), midvein flat to raised towards the base above, initially densely light brown tomentulose, glabrescent, distinctly raised below, persistently light reddish brown tomentulose, secondary veins 8-13 per side, slightly raised above and below, initially reddish tomentulose below, glabrescent, tertiary venation slightly raised above and below. Flowers unknown. Infructescence axis 5.6-15.4 cm long, 2.8-3.5 mm in diam., unbranched, densely light reddish tan tomentose; pedicels in fruit 3-4 mm, c. 1.1 mm in diam., reddish tomentulose. Fruit ellipsoid, 1.4-3.1 cm long, 1.1-2.3 cm in diam, glabrous, apex acute and slightly curved, sometimes with an apiculum to 1 mm, mesocarp (fruit wall) 3-4.7 mm thick, rendering the fruits hard and woody; seed flattened ellipsoid, 5-17 × c. 13 × c. 12 mm.

Etymology. – The epithet australis refers to the southernmost occurrence of the genus Beguea in Madagascar.

Conservation status. – Despite the very restricted Area of Occupancy within well-protected Andohahela National Park ( Fig. 4 ), there appear to be no current threats, and thus Beguea australis 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 australis is known from only two collections made in humid forest at Andohahela National Park ( Fig. 4 ). It can be easily recognized from all other species of Beguea by its large leaves with 12-30 leaflets whose apex is usually deeply emarginate, and its large woody fruits with a wall 3-4.7 mm thick ( Fig. 5 ).

Paratypi. – MADAGASCAR. Prov. Toliara: Anosy Region, RNI 11 , Andohahela , Parcelle 1 , Isaka Ivondro , 24̊40’S 46̊52’E, 100-500 m, 12-23.VI.1993, fr., Randriamampionona 454 ( BM, G, K, MO, NY, P, TAN, US).

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. 5. – Begueo oustrolis G. E. Schatz, Gereau & Lowry. A. Fruiting branch; B. Leaflet (lower surface); C. Leaflet (upper surface); D. Fruit (with close-up of surface); E. Section of fruit. [Rondriomompionono 633, MO] [Drawing: R. L. Andriamiarisoa]