Polygala retamoides (H. Perrier) Wahlert, Phillipson & G. E. Schatz

Wahlert, Gregory A., Phillipson, Peter B. & Schatz, George E., 2013, Lectotypifications and a new combination in Polygala L. (Polygalaceae) from Madagascar, Candollea 68 (2), pp. 313-315 : 314-315

2. Polygala retamoides (H. Perrier) Wahlert, Phillipson & G. E. Schatz , comb. et stat. nova ( Fig. 2 ).

Ξ Polygala longeracemosa var. retamoides H. Perrier in Bull. Trimestriel Acad. Malgache ser. 2, 14: 10. 1932.

Lectotypus (designated here): MADAGASCAR. Prov. Fianarantsoa: Rocailles cipolins [marble outcrops], Ambatofinandrahana [20°35’S 46°49’E], II.1919, fl., Perrier de la Bâthie 12441 ( P [ P00375349 ]!; isolecto-: P [P00375350]!).

Observations. –P ERRIER DE LA BÂTHIE (1932) designated his own collection, Perrier de la Bâthie 12441, as the type of P. longeracemosa var. retamoides . The only known material of the collection are two specimens at P, both of which are annotated with this name in Perrier de la BÂthie’s handwriting and both bear “Type” labels. We designate the sheet [P00375349] as the lectotype because it includes complete stems and inflorescences, as well as the woody base of the stem - an important morphological feature lacking on the sheet [P00375350].

Polygala retamoides is similar to P. longeracemosa by its habit, racemose inflorescence, and morphology of the flowers and seeds, but it differs by its densely pubescent stems (vs. glabrous to sparsely pubescent in P. longeracemosa ) and its smaller leaves (when present) up to 1.2 × 0.2 cm (vs. leaves up to 3.3 × 0.5 cm). Polygala retamoides also differs ecologically by being restricted to marble and quartzite substrates, whereas P. longeracemosa grows on soils derived from laterite and gneiss.

Distribution and habitat. – Polygala retamoides is restricted to high elevation grasslands on thin, rocky soils overlaying marble and quartzite substrates from 1300-1800 m, near Ambatofinandrahana, Fianarantsoa Province in the eastern part of the Itremo Complex ( Fig. 1 ).

Conservation status. – Data on the occurrence of P. retamoides is very limited, with only two of the eight known gatherings bearing precise geo-references. However all of these were apparentlymade nearthe town of Ambatofinandrahana, and none are known from the western part of the Itremo Complex which is now under temporary protection as a new protected area. These gatherings probably represent a single location and sub-population with a highly restricted Extent of Occurrence and Area of Occupancy of no more than a 10 km 2 in an area that is under considerable human pressure from fire and mining; Polygala retamoides is therefore assigned apreliminary conservation status of “Critically Endangered” [CR B1ab(i,ii,iii,v)+2ab(i,ii,iii,v)]. It is interesting to note that other species also appear to be endemic to the marble outcrops near Ambatofinandrahana but are not known from elsewhere in the Itremo Complex, for example Buxus cipolinica Lowry & G. E. Schatz (LOWRY & SCHATZ, 2006), suggesting the importance of this area to be brought into the protected area network of Madagascar.

Additional material examined. – MADAGASCAR. Prov. Fianarantsoa: Ambatofinandrahana, [20°35’S 46°49’E], X.1963, fl., Bosser 18119 ( P!); ibid. loc., 1964, fl., Bosser 19611 (P!); au S d’Ambatofinandrahana , [20°35’S 46°49’E], 13.XII.1976, fl., Cremers 3645 ( P!, TAN!); env. d’Ambatofinandrahana [20°37’19”S 46°50’09”E], 1600-1800 m, 21.II.1938, fl., Decary 13174 ( MO!, P [2 sheets]!); Ambatofinandrahana [20°35’S 46°49’E], III.1960, fl., Keraudren 219 ( P!); Mahavanino, 7 km au S d’Ambatofinandrahana, sur la route de Fenoarivo, lieu-dit de Analalehibe, Ambatofinandrahana , 20°37’43”S 46°50’32”E, 1350 m, 19.XI.1993, fl., Labat & al. 2370 ( K!, MO!, P [ P001718 ]!, TAN!); Ambatofinandrahana, 9km from Ambatofinandrahana, 20°36’47”S 46°49’56”E, 1398 m, 18.III.2004, fl., Skema & al. 46 ( MO!, TAN).

Figures

Fig. 2. – Living plant of Polygala retamoides (H. Perrier) Wahlert, G. E. Schatz & Phillipson, growing in its natural habitat on the marble outcrops south of Ambatofinandrahana. [Labat & al. 2370] [Photo: J.-N. Labat]

Fig. 1. – Distribution of Polygala longeracemosa H. Perrier (circles) and Polygala retamoides (H. Perrier) Wahlert, G. E. Schatz & Phillipson (triangles) in Madagascar mapped on the biogeographic zones of CORNET (1974).