Diospyros ambanjensis G.E. Schatz & Lowry, 2021

Schatz, George E., Lowry Ii, Porter P., Rakouth, Hasina N. & Randrianaivo, Richard, 2021, Taxonomic studies of Diospyros (Ebenaceae) from the Malagasy region. VI. New species of large trees from Madagascar, Candollea 76 (2), pp. 201-236 : 202-204

Diospyros ambanjensis G.E. Schatz & Lowry , sp. nov. ( Fig. 1).

H o l o t y p u s: M A D A G A S C A R. R e g. D i a n a [ Pr o v. Antsiranana]: forêt de Bekalonoro, 19.IX.2013, fr., Rasoanaivo 93 (MO-6857393!; iso-: G [ G00341884 ]!, P [ P01047888 ]!, TAN!) .

Diospyros ambanjensis G.E. Schatz & Lowry resembles other members of the Tetraclis group in having fauve to rusty indumentum, leaves generally with a mucronate apex, male flowers borne in cymose to pseudo-umbellate inflorescences, and often valvate corolla aestivation, but is distinguished by having spiral to pseudo-verticillate phyllotaxy, the shoot apex bearing numerous cataphylls prior to extension, and large leaves (11–37 × 2.4–5.5 cm).

Tree 6–16 m tall, 12–30 cm DBH. Young stems terete, densely covered with erect, brown to fauve trichomes c. 0.2–0.3 mm long, the shoot apex densely covered with numerous (c. 80) cataphylls prior to extension. Leaves arranged spirally to pseudo-verticillate along stem; lamina 11–37 × 2.4– 5.5 cm, narrowly oblanceolate, coriaceous, sparsely covered above with erect, golden to fauve trichomes c. 0.8– 1.2 mm long, more densely along the midvein, or glabrous, sometimes drying somewhat glaucous, initially rather densely covered below with erect, golden to fauve trichomes, more densely along the midvein, glabrescent, base long attenuate and slightly decurrent along petiole, margin revolute and densely ciliate initially, glabrescent, apex acute to rounded with a distinct mucron to 6 mm long, midvein impressed to flat above, distinctly raised below, venation eucamptodromous to weakly brochidodromous, often indistinct, with 13–23 secondary veins per side, flat to slightly raised above and below, tertiary venation reticulate; petiole 8 –15 mm long, 2–3 mm in diam., densely covered with erect, brown to fauve trichomes c. 0.5–1 mm long. Male flowers borne in axillary, cymose to pseudo-umbellate inflorescences, composed of 3–7 flowers, the main axis (peduncle) 15– 40 mm long, 0.5–1 mm in diam., densely covered with erect, fauve trichomes c. 1.5–2 mm long, pedicel 3–6 mm long, 1 – 1.5 mm in diam., densely covered with fauve trichomes c. 0.5– 0.8 mm long; calyx urceolate, 4 × 4 mm, irregularly 4-lobed, the lobes 1–2 × 2–3 mm, triangular, densely covered with semi-erect, fauve trichomes c. 0.2–0.3 mm long; corolla narrowly oblongoid-ellipsoid, 7–9 mm long, densely covered outside with appressed, fauve trichomes c. 0.8– 1 mm long, 4-lobed, the lobes valvate, 2–3 × 2–3 mm, triangular; stamens 26, subsessile, attached to the corolla at two levels, just above the middle and c. 1 mm higher, anthers 2–3 mm long, narrowly sagittate; pistillode narrowly ovoid, 5 mm long, 2 mm in diam., densely covered with stiff, semi-appressed, fauve trichomes c. 1 mm long, crowned by 2–3(–4?) stylodes. Female flowers axillary, solitary, sessile to subsessile, subtended by several ovate bracts 4–6 × 4–5 mm, apex abruptly acuminate; calyx urceolate, 8–9 × 9–10 mm, 4-lobed, the lobes broadly triangular to ovate, 3–5 × 5–7 mm, apex abruptly acuminate, densely covered outside and inside with erect, chocolate brown trichomes c. 0.2–0.3 mm long; corolla ellipsoid, 13 mm long, 9–10 mm in diam., densely covered outside with appressed, chocolate brown trichomes c. 0.8–1 mm long, except at base, glabrous inside, 4-lobed, the lobes valvate, 2– 3 × 3–4 mm, triangular, staminodia absent; ovary spherical, 7 mm in diam., densely covered with semi-appressed, stiff, chocolate brown to fauve trichomes c. 0.5 mm long, styles 4, 3 mm long, 0.6 mm in diam., fused for 1 mm at the base, densely covered with golden fauve trichomes c. 0.5–0.8 mm long at the base, progressively shorter toward the glabrous apex; stigma irregularly lobed and flattened, 1–2 mm across; ovules 8. Fruits solitary, axillary, sessile to subsessile; fruiting calyx accrescent, 14–16 mm × c. 25 mm, the lobes 16–21 × 13–19 mm, margins flat, densely covered with very short, erect, fauve trichomes c. 0.5–0.8 mm long; fruit spherical to slightly ellipsoid, 35 –40 mm in diam., initially densely covered with appressed and erect, fauve trichomes c. 1–1.5 mm long, glabrescent except for the areas protected by the calyx. Seeds not seen.

Vernacular names. – “Hazojoby” (Rasoanaivo 93), “Mapingo”

(Service Forestier 10640).

Distribution and ecology. – Diospyros ambanjensis is known from the Ampasindava and Ambato Peninsulas and from Ankitsika ( MADAGASCAR CATALOGUE, 2021), all of which are located in the Sambirano region of northwestern Madagascar. It occurs in low-elevation subhumid forest.

Phenology. – Material of Diospyros ambanjensis has been collected in flower in November and December, and fruits have been collected in September.

Conservation status. – Diospyros ambanjensis has a geographic range in the form of an Extent of Occurrence of 1703 km ² and a minimum Area of Occupancy of 20 km ². It is present in the Ampasindava protected area, but elsewhere it is threatened by forest clearing for agriculture, fire, grazing, and exploitation for firewood and house construction material, all of which will result in continuing decline. With respect to the most serious plausible threat of forest clearing for agriculture, D. ambanjensis exists at five locations, and was recently assessed for its risk of extinction as “Endangered” [EN B1ab(i,ii,iii,iv,v)+ 2ab(i,ii,iii,iv,v)] ( IUCN, 2021).

Notes. – Diospyros ambanjensis is a member of the Tetraclis group, characterized by often fauve to rusty indumentum, leaves generally with a mucronate apex, male flowers borne in cymose inflorescences, and often valvate corolla aestivation. Other members of the group include D. clusiifolia , D. erythrosperma , D. fuscovelutina , D. parifolia H. Perrier , D. urschii H. Perrier , and D. vescoi Hiern , as well as five additional new species described below (viz. D. antsirananae G.E. Schatz & Lowry , D. beberonnii G.E. Schatz & Lowry , D. crassipedicellata G.E. Schatz & Lowry , D. mimusops G.E. Schatz & Lowry , and D. rakotovaoi G.E. Schatz & Lowry ) and several others awaiting description. Within the Tetraclis group, D. ambanjensis can be distinguished by its spiral to pseudo-verticillate phyllotaxy, the shoot apex bearing numerous cataphylls prior to extension.

Additional specimens examined. – MADAGASCAR. Reg. Diana [Prov. Antsiranana]: Ampasindava, forêt de Betsitsika, 4.XI.2009, ♂ fl., Gautier et al. 5309 ( G, P) ; Ambato Forêt Classée, 22.XI.1996, ♀ fl., Randrianaivo et al. 24 ( MO, P, TAN) ; Ankitsika, Ambanja, 8.IX.1954, ♂ fl., Service Forestier 10640 ( P, TEF) ; Ampasindava, forêt de Bongomihiravavy, 13.XII.2008, ♂ fl., Tahinarivony et al. 211 ( G, P, TEF) .

Diospyros amborelloides G.E. Schatz & Lowry , sp. nov. ( Fig. 2A , 3).

Holotypus: MADAGASCAR. Reg. Atsinanana [Prov. Toamasina]: Betampona Strict Nature Reserve, 13.I.2017, Schatz et al. 4466 (MO-6443100!; iso-: BR!, CAS!, G [ G00341895 ]!, K!, P!, TAN!, WAG!, W!) .

Diospyros amborelloides G.E. Schatz & Lowry most closely resembles D. erinacea (H. Perrier) G.E. Schatz & Lowry in having elliptic leaves that are chartaceous to subcoriaceous and have an attenuate base, axillary cymose male inflorescence with ellipsoid male flower buds, 1-several ovoid fruits per leaf axil, and a cupular fruiting calyx with an entire margin, but differs by having leaves with an acute to acuminate apex (vs. rounded) and a larger and wider lamina (largest blade 9.5 –15.5 × 4.5–7.2 cm vs. 6–7.5 × 2 –3.1 cm), and larger fruit (11 × 6.5–7 mm vs. 6–7 × 5 mm).

Tree 4–18 m tall, 12–40 cm DBH. Young stems terete, glabrous. Leaves distichous, lamina 8–15.5 × 3.6–7.2 cm, elliptic, membranous, glabrous above and below, base long attenuate, margin flat, apex acute to acuminate, acumen 5–15 mm long, midvein flat to very slightly raised above, raised below, narrowing from the base to the apex, venation brochidodromous, with 7–12 secondary veins per side, slightly raised above and below, tertiary venation reticulate, weakly raised above and below; petiole 3–10 mm long, 1 mm in diam., glabrous. Male flowers in axillary cymose inflorescences, with 5–8 inflorescences per node, each with 1–5 flowers, 9–21 mm long, the axes slender, 0.5 mm in diam., moderately covered with semi-erect, grayish trichomes 0.1–0.2 mm long; flowers subsessile; calyx urceolate, 2.5–3 × 2.5–3 mm, unlobed, the margin entire, sparsely covered outside with appressed, grayish trichomes 0.1–0.2 mm long, glabrous inside; corolla in bud black, densely covered outside with appressed black trichomes 0.2 mm long, glabrous inside; stamens 10–20, inserted at the base of the corolla in a single whorl, filaments 0.2 mm long, anthers 1.5 mm long, lanceolate; pistillode absent. Female flowers not seen. Fruits axillary, 2–3 infrutescences per axil, each with 1–3 fruits, often with evidence of 4 total subsessile flowers per female inflorescence, the axes densely covered with semi-erect, grayish trichomes 0.1– 0.2 mm; fruiting calyx cupuliform, 3.5 – 5 × 6– 8 mm, entire, sparsely covered with semi-erect, grayish trichomes 0.1–0.2 mm long, glabrescent; fruit ovoid, 11 × 6.5–7 mm, glabrous, apex acute, crowned by the style/stigma remnant 1 mm long. Seeds 4, ovoid, 6 × 2–3 mm, black, shiny.

Etymology. – The specific epithet refers to the fact that male individuals of Diospyros amborelloides in flower resemble Amborella trichopoda Baill. (Amborellaceae) , an emblematic species endemic to New Caledonia whose phylogenetic position is sister to all other flowering plants ( PONCET et al., 2019).

Vernacular names and uses. – “Hazomafana” (Réserves

Naturelles 9127, Service Forestier 6149, Service Forestier 21889). Furniture and house construction (Service Forestier 21889).

Distribution and ecology. – Diospyros amborelloides occurs primarily in northeastern Madagascar, from Betampona reserve north to the area around the Baie d’Antongil, with outlying subpopulations in the Galoko-Kalobinono and Montagne d’Ambre protected areas in the northwest ( MADAGASCAR CATALOGUE, 2021). It occurs in low- to midelevation humid forest.

Phenology. – Flowering material of this species has been collected in September, and fruits have been collected in March, July, September, November, and December.

Conservation status. – Diospyros amborelloides has a geographic range in the form of an Extent of Occurrence of 45,633 km ² and a minimum Area of Occupancy of 36 km ². It is present in four protected areas, Betampona, Masoala, Montagne d’Ambre, and Zahamena. Outside of the protected areas, it is threatened by forest clearing for agriculture, fire, grazing, and exploitation for firewood and house construction material, all of which will result in continuing decline. With respect to the most serious plausible threat of forest clearing for agriculture, D. amborelloides exists at nine locations, and was recently assessed for its risk of extinction as “Vulnerable” [VU B2ab(i,ii,iii,iv,v)] ( IUCN, 2021).

Notes. – Diospyros amborelloides most closely resembles another humid forest species occurring in eastern Madagascar, D. erinacea , with which it shares elliptic, chartaceous to subcoriaceous leaves with an attenuate base, axillary cymose male inflorescences, ellipsoid male flower buds, ovoid, acorn-like fruits borne singly or more often in groups of up to 4–5 per leaf axil, and a cupular fruiting calyx with an entire margin. Diospyros amborelloides can be distinguished from D. erinacea by having leaves with an acute to acuminate (vs. rounded) apex and an elliptic (vs. narrowly elliptic) lamina, the largest of which measures 9.5–15.5 × 4.5–7.2 cm (vs. 6–7.5 × 2–3.1 cm), and fruit that are 11 × 6.5–7 mm (vs. 6–7 × 5 mm).

Additional specimens examined. – MADAGASCAR.Reg. Analanjirofo [Prov. Toamasina]: Vavatenina, RNI de Zahamena, 9.VII.2003, y.fr., Andrianjafy et al. 395 ( CNARP, MO, P, TEF) ; Maroantsetra, Anjahana, Hiaraka, 200 m, 3.IX.2002, ♂ fl., Antilahimena 1329 ( MO, P, TAN) ; Maroantsetra, Antsirabesahatany, Anjiahely, 23.XII.2002, y.fr., Antilahimena 1587 ( MO, P, TAN) ; Anjorolava, Marosoraka, Maroantsetra, 27.IX.1952, ♂ fl., Service Forestier 6149 ( MO, P, TEF) ; Fénérive, Tanambao, Vatofasika, 25.IX.1964, ♂ fl.,

Figures

Fig. 2. – Photographs of Diospyros L. species. A. Diospyros amborelloides G.E. Schatz & Lowry, branch with immature fruit; B–D. Diospyros antsirananae G.E. Schatz & Lowry: B. Branch with fruit; C. Branch with fruit; D. fruit; E–F. Diospyros bardotiae H.N. Rakouth, G.E. Schatz & Lowry: E. Branch with immature fruit; F. Immature fruits. [A: Rakotovao et al. 3882; B: Rakotonandrasana et al. 904; C–D: Rakotoarivelo 152; E: Randrianaivo 3273; F: Randrianaivo 3279] [Photos: A: C. Rakotovao; B, E–F: R. Randrianaivo;C–D: N. Rakotoarivelo]