Typus: Madagascar. Prov. Antsiranana: Région SAVA, sous-préfecture de Vohemar, commune rurale de Daraina, forêt de Bekaraoka, partie N, 13°07′06″S 49°42′34″E, 420 m, 17.I.2005, fl., Nusbaumer & Ranirison LN 1420 (holo-: G [G00019278]!; iso-: K!, MO!, P [P00722548]!, TEF!).

Eremolaena darainensis Nusb. & Lowry differs from E. humblotiana Baill. by its smaller leaves, its flowers born singly (vs. in pairs) and its shorter sepals, and from E. rotundifolia (F. Gérard) Danguy by its stellate-lanate indument adjacent to the primary vein on the abaxial surface of the leaf (vs. absent), its smaller and less dense strigose-stellate indument on the sepals, and its presence in semi-deciduous forest on granite (vs. littoral forest on sand)

Small trees 8–12 m, 10–20 cm DBH, branched. Branches gray brown to reddish, glabrescent, with grayish lenticels, bark smooth; twigs of current year flattened, reddish-brown pubescent with gray to whitish stellate-strigose scattered trichomes. Leaves ovate to obovate, green, slightly discolorous, whitish on abaxial surface (brown when dry), chartaceous, 30–55 × 25–43 mm, 1-1.4(-1.7) times as long as wide, with erect white stellate indument 0.4-0.8(-1. 1) mm long on abaxial surface adjacent to the primary vein, glabrous elsewhere, base subcordate to attenuate, margin flat in dry material, irregularly and weakly undulate when fresh, apex emarginate (rarely almost round), venation brochidodromous, with (5 or) 6 to 8 pairs of alternate to subopposite secondary veins, primary and secondary veins raised below, secondary and tertiary venation dark green, brown to purplish black in dry material, with sparse stellate-strigose indument on the venation of both surfaces and along the margin; petiole 8–17 mm long, with gray to whitish stellate-strigose indument, adaxially canaliculate; stipules triangular, 1.5–3 × 1–2 mm, canaliculate, brown, with white stellate-strigose indument, caducous. Flowers solitary, erect; pedicel green, brown-blackish when dry, 4-14(-16) mm long, with sparse to dense gray to whitish stellate-strigose indument, especially toward the apex; bracts foliose, 2-4(-5) × 1-2 mm, triangular, then 1.5 × 1 mm, covered with both dense white stellate-strigose and reddish-brown indument, caducous; flower subtended by a 3-lobed collar, the lobes 1.2 × 1.5 mm, with dense whitish stellate-strigose indument, giving it a whitish cast in fresh material; sepals 5, green, blackish when dry, entire, unequal, the 2 external ones smaller, triangular to deltoid, coriaceous, 1.5–3 × 1–2 mm, green, slightly purplish when fresh, the 3 internal ones imbricate, usually clockwise but sometimes counter-clockwise, ovate, asymmetrical, 9–14 × 6– 9 mm, glabrous, coriaceous or membranaceous where overlapped by an adjacent sepal, with gray to whitish stellate-strigose indument (trichomes to 0.25–0.35 mm diam.) where overlapping an adjacent sepal, trichomes of the overlapping part less dense at anthesis on the left side than on the right side, such that the foliaceous part (blackish in dry material) is visible; petals 5, obovate, white, equal, usually overlapping counter-clockwise, sometimes clockwise, always in the opposite direction from the sepals, convoluted, sub-irregular, 19– 22 × 8–10 mm, glabrous on both surfaces, apex rounded; extrastaminal disc cupuliform, 1 mm high, with an irregular margin; stamens ca. 90 to 110, filaments slender, white, 4–8 mm long, glabrous, anthers brown, 1–2 × 1 mm, introrse, anther sacs often oblique; pollen pale yellow; ovary spherical to shortly conical, with dense, cream to yellowish stellate-strigose indument (glabrous at the apex), 3-locular; style cylindrical, erect, pale yellow, 5–6 mm long, glabrous; stigma pale yellow, 3-lobed, 2 mm long, crateriform, margin distinctly undulate. Fruit unknown.

Distribution and ecology. — Eremolaena darainensis is restricted to the Bekaraoka and Ampondrabe forests in the Loky-Manambato (Daraina) region in north-eastern Madagascar (Fig. 3). Among the more than 54,000 individual plants documented during recent floristic inventory work and vegetation studies conducted in this area, only 39 were found of E. darainensis (Nusbaumer & al., 2011), including just two fertile trees. Eremolaena darainensis is the northernmost member of the genus, separated by nearly 250 km from the closest known locality of E. rotundifolia (F. Gérard) Danguy just north of Cap Est, and almost 350 km from the most northern population of E. humblotiana Baill. Eremolaena darainensis is only known from flowering material gathered in January and February; no fruiting collections have yet been made. It grows in semi-deciduous (transitional) forest with a dense canopy reaching to 7– 12 m and a dense under-storey of shrubs. Our new species occurs at 250–550 m elevation and is usually found on fairly steep (20-40°) slopes in fine soil on rocky outcrops. The most abundant co-occurring species include, in decreasing order, Euphorbia geroldii Rauh (Euphorbiaceae), Asteropeia amblyocarpa Tul. (Asteropeiaceae), Cleistanthus suarezensis Leandri (Phyllanthaceae), and Rinorea angustifolia (Thouars) Baill. (Violaceae).

Conservation status. — Eremolaena darainensis is currently known form five subpopulations, all of which are encompassed within the Loky-Manambato forest, which has been accorded temporary protection by the Malagasy government as a “Station Forestière à usages Multiples” (SFUM, Multiple Use Forestry Station), which falls short of full protection, indicating that some continuing decline of the quality of the habitat can be projected. Therefore, with an Extent of Occurrence (EOO) of 81 km², an Area of Occupancy (AOO) of 54 km², and five locations (calculated following Callmander & al., 2007), as well as estimated number of mature individuals (based on extrapolation of the inventory data) of less than 2,500, with none of the five subpopulations estimated to contain more than 250 mature individuals, E. darainensis can be assigned a risk of extinction of “Endangered” [EN Blab(iii)+ 2ab(iii); C2a(i)] following the IUCN Red List Categories and Criteria (IUCN, 2012).

Notes. — Using the key to species of Eremolaena provided by Lowry & al. (2000), material of this new species would be identified as E. rotundifolia. It can, however, be distinguished from the two other members of the genus by several foliar and floral features, as well as differences in substrate preferences and geographic distribution (Fig. 3). In order to facilitate identification of material of Eremolaena, the following updated key is provided.

Paratypes. — Madagascar. Prov. Antsiranana: Région Sava, sous-préfecture de Vohemar, commune rurale de Daraina, forêt d'Ampondrabe, 12°57′07″S 49°41′36″E, 450 m, fl., 17.II.2005, Ranirison & Nusbaumer 936 (G [G00019280]!, K!, MO!, P [P00722550]!, TEF!).

Typus: Madagascar. Prov. Toliara: Région Anosy, Bemangidy, Commune Iabokoho, Fokontany Antsotso, Ivohibe forest, 24°34′10″S 47°12′37″E, 41 m, 24.V.2006, fr., Antilahimena 4876 (holo-: MO-6564308!; iso-: G!, K!, P [P00722627]!, TAN!, WAG!).

Schizolaena charlotteae Lowry & G. E. Schatz differs from its most similar congener, S. milleri Lowry & al., by its sparse grayish stellate indument obscuring the dark outer surface of the sepals beneath (vs. dense whitish stellate indument not obscuring the sepal surface), large petals 10– 14 mm long that are bright pinkish red grading to yellow toward the margins (vs. 7–8 mm long and white), 90 to 100 stamens (vs. ca. 265), and an involucre in fruit with processes that are 10–16 mm long and 1 mm wide below the apex (vs. 3–9 mm long and 0.2–0.5 mm wide).

Shrubs to trees 2–15 m tall. Twigs glabrous or sparsely hispidulose, with small, elongate lenticels. Leaves elliptic to slightly ovate or obovate, chocolate brown above (in dry material), lighter and more orangish below, subcoriaceous, (3-)4-7.5 × (1.2-) 1.5-3 cm, glabrous on both surfaces, base broadly cuneate to rounded, margin entire, minutely thickened, slightly revolute, apex acute to nearly rounded, sometimes slightly retuse, venation brochidodromous, with 6 to 9 pairs of alternate to subopposite, weakly raised secondary veins joined by rounded arches, midrib plane above, raised below; petiole 6– 9 mm long, glabrous or with scattered stellate indumentum; stipules narrowly ovate to ovate, membranous, with nearly obscure parallel venation, 10–12 × 5–7 mm, base rounded, apex acute, caducous, leaving a small scar. Inflorescence comprising 1 or 2 (rarely 3) unbranched axes, each with a pair of bracts borne near the middle and hearing 1 or 2 terminal flowers, axis ca. 10 mm in bud, expanding to 20–22 mm at anthesis, moderately to densely papillose stellate-strigose, bracts broadly elliptic to nearly circular, 4 × 3–4 mm, apex rounded, minutely stellate on abaxial surface, pubescent on adaxial surface, caducous, ultimate axes below the involucre 6–10 mm long, moderately papillose stellate, involucre in flower broadly cupuliform, with numerous cylindrical to narrowly triangular teeth, moderately to densely papillose stellate on both surfaces, containing 1 or 2 sessile flowers; sepals 3, imbricate, broadly ovate, adaxially concave, 9–10 × 6 mm at anthesis, with short stellate-papillose indumentum on the exposed part of the abaxial surface, the portion hidden by the overlapping adjacent sepal with both papillose stellate and short lanate indumentum, margins entire, the hidden portion tinged deep pinkishred, apex rounded to acute; petals 5, obovate, bright pinkish red, yellow toward the margins, slightly succulent in fresh material, chartaceous when dry, 10–14 × 6–8 mm, with dense, appressed sericeous indument in the central portion of the abaxial surface, glabrous toward the entire margins, glabrous on the adaxial surface, apex rounded to broadly acute; stamens ca. 90–100, filaments slender, ca. 4 mm long, glabrous, anthers elliptic to nearly circular, 0.8 mm long, introrse, dehiscent through longitudinal slits; ovary broadly conical, densely white woolly tomentose, 3-locular; style cylindrical, erect, ca. 9 mm long, stigma terminal, minutely 3-lobed, glabrous. Fruit subglobose, ca. 15 mm in diam., with dense stellate indumentum, most trichomes with the central branch much longer than the others, capsule dehiscent by 3 longitudinal sutures, exocarp cartilaginous, rugose, dry sepals and filaments persistent; involucre expanded, broadly cupulate, fleshy and sticky, green in nearly mature fresh material, ca. 25 × 20 mm, sparsely stellate pubescent to glabrous on both surfaces, with 5 broadly ovate, nearly equal lobes divided ca. 1/2 of the way to the base, each lobe with 7 to 10 narrowly triangular to lanceolate or cylindrical, occasionally bifid processes, each 7–16 mm long, ca. 1 mm wide just below the apex; seeds 1 per locule.

Distribution and ecology. — Schizolaena charlotteae is known only from lowland humid forest at Bemangidy-Ivohibe, situated just a few km to the west of the village of Antsotso in the Tsitongambarika New Protected Area, which encompasses much of the Vohimena range to the north of Tolagnaro (Fig. 3).

Conservation status. — The sole forest (Bemangidy-Ivohibe) from which Schizolaena charlotteae is currently known has temporary protection status as part of the larger Tsitongambarika New Protected Area. However, until permanent protection has been established, the forest is still potentially subject to local disturbance and illicit exploitation, especially along its eastern edge where S. charlotteae has been collected. Therefore, with a very restricted AOO of ca. 20 km² and only a single location, coupled with the possibility for rapid decline due to the effects of human activities if protection of the Bemangidy-Ivohibe forest is not maintained, S. charlotteae can be assigned a risk of extinction of “Vulnerable” [VU D2] following IUCN Red List Categories and Criteria (IUCN, 2012).

Notes. — Schizolaena charlotteae is part of a morphologically coherent group of species that also includes S. laurina Baill., S. milleri Lowry & al. and S. rosea Thouars, characterized by several features including: glabrous petioles and young branches; dense, straight, appressed indumentum on the abaxial surface of the petals; ovate and usually persistent stipules and inflorescence bracts; and an involucre in fruit that is broadly to narrowly cupuliform or funnelform. Indeed, one of the collections of our new species, Service Forestier 28662, was originally assigned by Lowry & al. (1999) to S. milleri, known otherwise only from littoral forest on white sand and low elevation humid forest on latente, from near the village of Ambavala (north of Sambava) extending south to Foulpointe, fully 800 km to the north of the only known locality of S. charlotteae.

Using the key to species of Schizolaena provided by Lowry & al. (1999), material of this new species would be identified as S. milleri. However, it differs in several features of the flower and fruiting involucre, as indicated below in Table 1. Specimens of Service Forestier 28662 at P were originally annotated as ‘S. delphinensis’ by J.-F. Leroy, but the name was never validly published.

The Bemangidy-Ivohibe forest has been the focus of intensive botanical inventory conducted over the last decade by teams from the Missouri Botanical Garden and the Rio Tinto-QMM mining company in order to assess its suitability as a conservation offset site (BirdLife International, 2011; Temple & al. 2012). Dozens of new taxa have been documented from Bemangidy-Ivohibe, some of which have already been described, including new genera of Sapotaceae, Bemangidia L. Gaut. (Gautier & al., 2013) and Asteraceae, Lowryanthus Pruski (Pruski, 2014) and new species in several families such as Gnidia razakamalalana Z. S. Rogers (Thymelaeaceae; Rogers, 2006), Ivodea anosiensis Rabarim. & al. and I. macrocarpa Rabarim. & al. (Rutaceae; Rabarimanarivo & al., in press), and Micronychia bemangidiensis Randrian. & Lowry (Anacardiaceae; Randrlanasolo & Lowry, 2009).

Etymology. — This species is named in honor of our friend and colleague Professor Charlotte Rajeriarson, recently retired from the Université d'Antananarivo, who has played a key role in training an entire generation of Malagasy botanists, and who served as the first President of the IUCN Madagascar Plant Specialist Group, helping to ensure the successful establishment of this important national initiative.

Paratypes. — Madagascar. Prov. Toliara: Région Anosy, Tsitongambarika, Commune Iabokoho, Fokontany Antsotso, forêt dense humide d'Ivohibe, 24°34′S 47° 11′E, 5.IV.2008, fl., Ramison & al. 581 (G, MO-6564309, P [P00722628], TEF); ibid, loc., 24°34′04″S 47°12′37″E, 90 m, 9.II.2006, fl., Randriatafika & al. 653 (MO, P [P00722633], TEF); Forêt de Bemangidy, entre les fleuves Vatomena et Manambato, au N de Ft. Dauphin, [24°34′S 47°12′E], 14.XII. 1968, fl., Service Forestier 28662 (MO-5189144, P [P00490165, P00490166]).

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 km² 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″S47°00′07″E, 179 m, 19.II.2009, fr., Rakotovao 4343 (G!, K!, MO-6404251, P [P00722636], TAN. WAG!).