Perrierodendron, Cavaco, 1951

Lowry Ii, Porter P., Haevermans, Thomas, Labat, Jean-Noël, Schatz, George E., Leroy, Jean-François & Wolf, Anne-Elizabeth, 2000, Endemic families of Madagascar. V. A synoptic revision of Eremolaena, Pentachlaena and Perrierodendron (Sarcolaenaceae), Adansonia (3) 22 (1), pp. 11-31 : 19-20

Key to the species of Perrierodendron

1. Leaves and petioles pubescent even when mature, indumentum totally covering the abaxial surface; lateral branches with leaf scars almost as wide as the stem, internodes 1.5-3(-4) mm long, giving the stem an evident “zig-zag” appearance; involucre in fruit forming a minute cupule, apex of fruit tapering into a prominent rostrum ca. 1/2 the length of the fruit body; Tapia woodland on quartzite, Itremo. 4. P. quartzitorum

1’. Leaves and petioles sparsely pubescent to glabrescent; lateral branches with leaf scars less than 1/2 as wide as the stem, internodes at least (3-) 6-12 mm long, branches not distinctly “zig-zag”; involucre in fruit forming an evident cupule, apex of fruit rounded or with a short rostrum not exceeding 1/4 the length of the fruit body ...... 2

2. Flowers borne individually at the apex of an unbranched peduncle (5-) 9-14 mm long, each peduncle borne singly in the axil of a highly reduced leaf (resembling a bracteole) on a short, naked branchlet; dry forest on sand, lower Rodo (= Irodo) basin ........................................................................................ 5. P. rodoense

2’. Flowers sessile or subsessile, solitary or several borne along a distinct inflorescence axis (some flowers abortive but leaving an evident scar) .......................................................................................................... 3

3. Leaves shiny above, with scattered stellate indumentum mostly on the primary and secondary veins; inflorescence axes usually 2-5 cm long; fruit obovoid, weakly bi-lobed toward the apex, 2-seeded, covered with very short stellate indumentum, stamens not persistent; involucre reflexed, margin undulate .......... 2. P. capuronii

3’. Leaves dull above, covered with dense stellate indumentum throughout (nearly glabrescent in some old leaves); inflorescence axes less than 1.5 cm long or flowers solitary and subsessile; fruit ovoid, unlobed, 1- seeded, evidently woolly hirsute with stellate hairs comprising short and much elongated branches, base surrounded by the persistent stamens; involucre appressed to the fruit, forming a distinct cupule, sometimes asymmetrically accrescent............................................................................................................................ 4

4. Fruit exocarp distinctly ribbed on outer and inner surfaces, apex acute, with a short, blunt protuberance, endocarp thick, almost bony; sepals ca. 8-9 mm long; petals ca. (10-) 11-13 mm long; dry forest, Analalava, Bongolava, Ankarafantsika RNI .......................................................................................... 1. P. boinense

4’. Fruit exocarp smooth (unribbed) on outer and inner surfaces, apex extended into a short, conic rostrum, endocarp thin, crustaceous; sepals ca. 5-6 mm long; petals ca. 8-9(-10) mm long; dry forest, Ambasy, Ingaro, Isalo PN, Sakaraha ...................................... ....................................................... 3. P. occidentalis