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

PERRIERODENDRON Cavaco

Bull. Mus. Natl. Hist. Nat., sér. 2, 23: 138 (1951).

TYPE. — Perrierodendron boinense (H. Perrier) Cavaco.

C AVACO (1951) described Perrierodendron based on a species originally assigned to Eremolaena by PERRIER DE LA BÂTHIE (1925), but which was clearly distinct from that genus on the basis of several features, especially the presence of an indehiscent, 2-locular fruit subtended by an accrescent, entire involucre. CAPURON (1970) mentioned two additional species, but declined to describe them for lack of sufficient material. J.-F. LEROY began preparing a manuscript describing these and two additional new species shortly after CAPURON’ s death in 1971, but it remained unpublished at the time he passed away in early 1999. A careful re-evaluation of his work and comparison of the material of Perrierodendron now available shows that five well delimited species can indeed be recognized, four of which are newly described here. Two of these taxa are represented by several collections in flower and fruit, and although the other two are known from very limited material, they appear to be amply distinct to justify describing them at this time.

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

Clé des espèces de Perrierodendron

1. Feuilles et pétioles pubescents même à maturité, indument couvrant entièrement la face abaxiale; cicatrices foliaires sur les rameaux latéraux à peu près aussi larges que le rameau, entre-noeuds long de 1,5-3 (-4) mm, donnant aux rameaux une apparence évidente en « zig-zag »; fruit à involucre en cupule minuscule, apex du fruit atténué en un rostre proéminent ca. 1/2 de la longueur du corps de fruit; bois de Tapia sur quartzite, Itremo ...................................................................................................... 4. P. quartzitorum

1’. Feuilles et pétioles éparsement pubescents à glabrescents; rameaux latéraux avec des cicatrices foliaires couvrant moins de la moitié de la largeur des rameaux, entre-noeuds (3-) 6-12 mm de long, rameaux n’ayant pas une apparence en « zig-zag »; fruit à involucre en cupule évidente, apex du fruit arrondi ou avec un rostre court ne dépassant pas 1/4 de la longueur du corps du fruit .................................................................... 2

2. Fleurs naissant individuellement au sommet d’un pédoncule non ramifié long de (5-) 9-14 mm, les pédoncules solitaires à l’aisselle d’une feuille extrêmement réduite (ressemblant à une bractéole) sur un petit rameau nu; forêt sèche sur sable, bassin inférieur de la Rodo (= l’Irodo) .......................... 5. P. rodoense

2’. Fleurs sessiles ou subsessiles, solitaires ou regroupées sur un axe inflorescentiel distinct (quelques fleurs peuvent avorter en laissant une cicatrice bien visible) ............................................ ........................................ 3

3. Feuilles brillantes dessus, portant un indument étoilé épars surtout sur les nervures primaires et secondaires; axes inflorescentiels habituellement de 2-5 cm de longueur; fruit obovoïde, faiblement bilobé vers le sommet, 2-séminé, couvert d’un indument étoilé très court, étamines non persistantes; involucre réfléchi, marge ondulée .................................................................................................................... 2. P. capuronii

3’. Feuilles mates dessus, entièrement couvertes d’un dense indument étoilé (quelques vieilles feuilles presque glabrescentes); axe inflorescentiel de moins de 1,5 cm de longueur ou fleurs solitaires et sessiles; fruit ovoïde, non lobé, 1-séminé, couvert d’un indument hirsute laineux composé de poils étoilés formés de branches courtes et plus longues, base entourée par les étamines persistantes; involucre appliqué sur le fruit, formant une véritable cupule, parfois assymétriquement accrescent .......................................................... 4

4. Exocarpe du fruit distinctement côtelé sur les surfaces externes et internes, apex aigu, avec une protubérance courte peu visible, endocarpe épais, presque osseux; sépales d’environ 8-9 mm de longueur; pétales d’environ (10-) 11-13 mm de longueur; forêt sèche, Analalava, Bongolava, RNI d’Ankarafantsika .......... 1. P. boinense

4’. Exocarpe du fruit lisse sur les deux faces, apex étendu en un rostre conique court, endocarpe mince, cartacé; sépales d’environ 5-6 mm de longueur; pétales d’environ 8-9(-10) mm de longueur; forêt sèche, Ambasy, Ingaro, PN d’Isalo, Sakaraha ............................................................................ 3. P. occidentalis