Schizolaena parvipetala Randrian.

Lowry II, Porter P., Nusbaumer, Louis, Randrianasolo, Armand, Schatz, George E. & Hong-Wa, Cynthia, 2014, Endemic Families of Madagascar. XIII. New, restricted range species of Eremolaena Baill. and Schizolaena Thouars (Sarcolaenaceae), Candollea 69 (2), pp. 183-193 : 190-192

Schizolaena parvipetala Randrian. & Hong-Wa, spec. nova ( Fig. 5 ).

Typus: MADAGASCAR. Prov. Toliara: Région Anosy, Tolagnaro, Iabokoho , Antsotso , TGK 42 , forêt de Bemangidy , 24°35’17’’S 47°08’42”E, 28 m, [2008], fl., Randriatafika 877 (holo-: MO-6564307 !; iso-: G!, K!, MO- 6406252!, P [P00722634]!, TEF!).

Schizolaena parvipetala Randrian. & Hong-Wa differs from its most similar congener, S. gereaui Lowry & al., by its ovate to elliptic leaves (vs. elliptic to slightly obovate) with an acumen (5-) 7-14 mm long (vs. 3-6(-12) mm), the presence of two flowers per involucre (vs. one), smaller petals measuring 4-6 × 1.8-2 mm (vs. 10-14 × 7-8 mm), 30 to 40 stamens (vs. 100 to 120) with the filaments 3-3.5 mm long (vs. ca. 1.5 mm), and styles ca. 3.5 mm long (vs. ca. 2 mm).

Shrubs to small trees 2-6 m tall. Twigs glabrous to sometimes sparsely pubescent, with small, roundish lenticels. Leaves ovate to elliptic, medium brown above, light brown below (in dry material), chartaceous, 2-6 × 1.2-2.4 cm, glabrous on both surfaces, base rounded to truncate, margin entire, minutely thickened, slightly revolute and undulate, apex acuminate, acumen (5-) 7- 14 mm long, venation brochidodromous, with 8-12 pairs of alternate to subopposite, abaxially slightly raised secondary veins joined by depressed-rounded arches, midrib slightly canaliculate above, raised below; petiole 3-5 mm long, glabrous to sparsely stellate-strigose; stipules 2, united at their base, brownish when dry, lanceolate, 2-3.5 × 1-1.5 mm, membranaceous, somewhat triplinerved, glabrous on adaxial surface, stellate on abaxial surface, base truncate, margin entire, apex acute to rounded, caducous, leaving a small scar. Inflorescences axillary, 2-4-flowered, with 1 or 2 unbranched axes, each with a pair of basally connate bracts borne in the middle and bearing 2 terminal flowers, axes 2-3 mm long in bud, reaching 8 mm long at anthesis, densely short stellate, bracts brownish, widely ovate, 1 × 1.2 mm, base truncate, glabrous on adaxial surface, densely stellate on abaxial surface, membranaceous, caducous, leaving a rimmed scar, margin entire, apex rounded, ultimate axes below the involucre 1.5-4.5 mm long, densely stellate, involucre in flower a shallowly 5-lobed rim, densely papillose stellate on both surfaces, subtending 2 sessile flowers, lobes minutely crenate; sepals 3, imbricate, broadly ovate, adaxially concave, 3-4 × 2.5-2.8 mm at anthesis, glabrous on adaxial surface, densely stellate on the exposed part of the abaxial surface, the portion hidden by the overlapping adjacent sepal glabrous and darker-colored, base truncate, margin entire, apex acute to rounded, occasionally shallowly bifid; petals 5, white, oblong, chartaceous (in dry material), 4-6 × 1.8-2 mm, glabrous on both surfaces, base truncate, margin entire, apex rounded, caducous; disc cupuliform, denticulate, 0.8-1 mm long; stamens 30 to 40, filaments slender, often contorted in dry material, 3-3.5 mm long, glabrous, anthers ovoid to subglobose, 0.3-0.4 mm long, introrse, dehiscent through longitudinal slits; ovary ovoid to subglobose, 1.5-2.5 × 2 mm, densely white tomentose, 3-locular, style cylindrical, contorted in dry material, ca. 3.5 mm long, stigma terminal, truncate to slightly 3-lobed, glabrous. Fruit unknown.

Distribution and Ecology. – Schizolaena parvipetala , like S. charlotteae described above, appears to be restricted to lowland humid forest of southeastern Madagascar, where it has been recorded to the W of Mahatalaky and at Bemangidy-Ivohibe in the Tsitongambarika New Protected Area, respectively ca. 20 and 55 km N of Tolagnaro ( Fig. 3 ).

Conservation status. – Schizolaena parvipetala is known from only two localities, one of which (Bemangidy-Ivohibe) currently has temporary protection (but see the assessment of Schizolaena charlotteae above) while the other (W of Mahatalaky) lacks any protection. Therefore, with an AOO of ca. 20 km 2 and projected continuing decline as a result of forest conversion and degradation at the second location, S. parvipetala can be assigned a risk of extinction of “Endangered” [EN B2ab(ii,iii,iv,v)] following IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. As its name suggests, Schizolaena parvipetala stands out by having the smallest flowers of any member of the genus. It closely resembles S. gereaui , which also occurs in south-eastern Madagascar, and specimens would be identified as that species using the key provided by LOWRY & al. (1999). However, S. parvipetala differs by several foliar and floral characters, as summarized in Table 2 .

Paratypes. – MADAGASCAR. Prov. Toliara: Région Anosy, Tolagnaro, Iabokoho , Antsotso , TGK 42 , forêt de Bemangidy , 24°35’17’’S 47°08’42’’E, 28 m, s.d., fl., Randriatafika 876 ( MO- 6407630 , P [ P00722635 ], TAN); Mahatalaky, Farafara Vatambe , forêt humide de basse altitude de Farafara Andohavolo située au S du village de Farafara, 24°51’05’’S 47°00’07’’E, 179 m, 19.II.2009, fr., Rakotovao 4343 ( G!, K!, MO-6404251 , P [ P00722636 ], TAN, WAG!).

Figures

Fig. 5. – Schizolaena parvipetala Randrian. & Hong-Wa A. Branch with flowers; B. Detail of leaf; C. Peduncle with 2 flowers subtended by undeveloped involucre. [RandriataFika 877] [Drawing: R. L. Andriamiarisoa]

Fig. 3. – Geographic distribution of Eremolaena darainensis Nusb. & Lowry (stars), Schizolaena charlotteae Lowry & G. E. Schatz (circles) and Schizolaena parvipetala Randrian. & Hong-Wa (squares), mapped on the bioclimatic zones of Madagascar (after CORNET, 1974; see SCHATZ, 2000).