Noronhia myrtoides H. Perrier Noronhia obcordifolia

Hong-Wa, Cynthia, 2016, A taxonomic revision of the genus Noronhia Stadtm. ex Thouars (Oleaceae) in Madagascar and the Comoro Islands, Boissiera 70, pp. 1-292 : 183-188

55. Noronhia myrtoides H. Perrier in Mém. Inst. Sci. Madagascar, Sér. B, Biol. Vég. 2: 302. 1949 ( Fig. 40A).

Typus: M ADAGASCAR. Prov. Toliara: Ampandrandava, dans les rochers de Pisopiso, [ 24°02’S 45°42’E], 750 m, XI.1943, Seyrig 299 ( = Herb. Jard. Bot. Tan. 5392) (holo-: P [ P03558897 ]!) .

Description

Small trees to 5 m tall, trunk to 5 cm diameter; young twigs cylindrical, 0.6-1.3 mm diameter, glabrous; bark medium to light gray, smooth to slightly rugose. Leaves opposite, persistent; bud scales persistent; blades dark green above, lighter below, oblong to lanceolate, 4-8 3 1-2.5 cm, coriaceous, glabrous, domatia absent, base acute, margin slightly revolute, apex acute to acuminate, the acumen 1-8 mm long, midrib sunken above, slightly raised below, secondary veins barely visible, 7-11 per side, 3.5-11 mm apart, looping 0.5-3.5 mm from the margin; petiole light gray, 2.5-7.5 3 0.6-1.3 mm, entirely woody, glabrous. Flowers fasciculate; pedicel 3-7 mm long, glabrescent; calyx moderately pubescent to tomentose outside, glabrous inside, lobes deltate, 1-2 3 0.6-2 mm; corolla ivory white, cupuliform, 3.8-6 mm long, glabrous on both sides, the tube 2.5-4 mm long, lobes widely ovate, apex obtuse; corona present, 1-2 mm long, lobed; stamens 1.5-2.6 mm long, anthers widely ovate, 1.2-2.4 mm long; pistil 2-3.7 mm long, stigma capitate. Fruiting pedicel 4-9 3 0.7-1.4 mm; young fruits green, dark red when mature, ovoid to subglobose, 9-17 3 8.5-14.5 mm, surface smooth, sometimes covered with white dots, apex apiculate; dry pericarp 0.2-1.1 mm thick; endocarp woody; seed 5.5-11.5 3 4-9.5 mm.

Distribution, ecology and phenology

Noronhia myrtoides occurs in low- to mid-elevation dry forests and thickets from Bemaraha in the west to Andohahela in the south ( Fig. 36). It produces flowers and fruits throughout the year except in April and May.

Conservation status

The assessment included 20 collections representing 19 localities and resulted in an EOO of 78,840 km 2, an AOO of 92 km 2, and 21 subpopulations representing 17 locations, of which 11 occur within protected areas (Amoron’i Onilahy, Andohahela, Bemaraha, Beza-Mahafaly, Complexe zones Mangoky, Menabe-Antanimena, Vohidava-Betsimalaho, and Zombitsy). With a large EOO, an actual AOO that is likely larger than 2,000 km 2, and many locations that are well represented within the network of protected areas, N. myrtoides is assigned a preliminary status of “Least Concern”.

Notes

Noronhia myrtoides can be recognized by its habit (a small tree), oblong to lanceolate leaf blades with barely visible venation, and fasciculate white flowers. It differs from N. alleizettei by the shape of its leaves (oblong to lanceolate vs. narrowly elliptic) and the presence of a corona, and from N. buxifolia by the shape of its leaves (oblong to lanceo-late vs. ovate) and fruits (ovoid to subglobose vs. ovoid) and by the color of its flowers (white vs. red). The specimen of Humbert 5236 deposited at P, with duplicates housed in several other herbaria, bears the annotation “type”. However, in the protologue, PER-RIER DE LA BâTHIE (1949) designated Seyrig 299 ( = Herb. Jard. Bot. Tan. 5392) as the type and Humbert 12949 as a “co-type”; the former is therefore recognized here as the type and the latter as a paratype.

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Additional specimens examined

MADAGASCAR. Prov. Toliara: Ambatoabo, Andohahela PN, Mt Apiky , 24°47’19”S 46°43’04”E, 647 m, 18. I.2007, Andriamihajarivo et al. 1165 ( MO, P, TAN) ; Amboasary Sud, Marotsiraka, Ankotsy , 24°17’13”S 46°08’24”E, 513 m, 11.XI.2008, Andriamihajarivo et al. 1559 ( MO, P, TAN) ; c. 10 km N of Befandriana-Sud , 150 m, 21.XII.1961, Appert 51 ( MO) ; Befandriana-Sud , 150 m, 15. V.1905, Appert 201 ( MO) ; Vallée de la Sakoa, 23°42’S 44°46’E, 22.X.1940, Decary 16020 ( G, MO, P) ; vallée du Fiherenana , [ 23°18’S 43°38’E], 10-200 m, 14.IX.1924, Humbert & Perrier de la Bâthie 2575 ( P) ; vallée inférieure de l’Onilahy , [ 23°30’S 44°01’E], 10-50 m, 12.VIII.1928, Humbert & Swingle 5236 ( BR, K, P, WAG) ; de Tsivory à Anadabolava , [ 24°12’S 46°19’E], 300-400 m, XII.1933, Humbert 12329 ( P) ; Zombitsy ( Sakaraha ), 600-850 m, 26-29. III.1955, Humbert et al. 29649 ( G, MO, P) ; Anadabolava, Betsimilaho , 24°13’06”S 46°17’16”E, 299 m, 1.VII.2011, Letsara et al. 1287 ( CAS, MO) ; entre Tuléar et St. Augustin , 23°28’S 43°47’E, 31.III.1966, Peltier & Peltier 5827 ( MO, P) ; env. de Soahanina, [ 18°35’S 44°14’E], s.d., Perrier de la Bâthie 8812 ( P) ; sur la Sakoa, bassin de l’Onilahy, [ 23°43’S 44°47’E], VIII.1925, Perrier de la Bâthie 17363 ( P) ; Beza Mahafaly RS near Betioky , 23°40’S 44°39’E, 180 m, 26.X.1987, Phillipson 2455 ( MO, P, TAN) ; Near Beza Mahafaly RS, 23°58’S 44°39’E, 150 m, 28.XI.1987, Phillipson 2618 ( MO, P, TAN) ; Sakaraha, Mahaboboka, Ankasy forest , 22°49’03”S 44°16’47”E, 581 m, 22. II.2011, A. Randrianasolo et al. 1441 ( G, MO, P, TAN) ; Amboasary Sud, Mahaly, Anadabolava , 24°14’38”S 46°18’25”E, 263 m, 24.X.2007, Randriatsivery et al. 248 ( MO, P, TAN) ; Manja, Beharoana, Vondrove , 21°48’03”S 44°10’43”E, 86 m, 20.IX.2007, Rasoafaranaivo et al. 267 ( MO, P, TAN) ; Ambatoabo, Ankoba , 2 km E d’Imonty, 24°47’56”S 46°40’24”E, 160 m, 17.XI.2009, Ratovoson 1496 ( G, MO, P, TAN) ; Zombitsy PN, [ 22°46’S 44°42’E], 600 m, 21.III.1951, Service Forestier 3387 ( P, TAN, TEF) ; Ankaraobato, Morondava , [ 20°10’30”S 44°37’50”E], 0-50 m, 13.XI.1952, Service Forestier 6063 ( MO, P, TEF) ; Menabe, Andoharano , [ 19°42’S 44°33’E], 16.XII.1957, Service Forestier 17866 ( G, P, TEF) ; Betioky, near Analafaly , 23°39’S 44°38’E, 1. VI.1987, Sussman 153 ( MO) .

Photos: taken by respective coLLectors

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56. Noronhia obcordifolia Hong-Wa, spec. nova (Fig. 41).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA , Diégo II, Ramena, env. 2 km à l’O d’Andavakoera, près de la grotte et du campement la Casa Aventura, 12°19’57’’S 49°21’19’’E, 172 m, 4.VIII.2007, Hong-Wa et al. 535 (holo-: MO-6615565!; iso-: CNARP!, G [ G00341625 ]!, P!, TAN!) .

Diagnosis

Noronhia obcordifolia Hong-Wa can be distinguished from its congeners by its coriaceous, heart-shaped leaves and its apiculate fruits, somewhat covered with a white pellicle.

Description

Shrubs to 4 m tall; young twigs cylindrical, 1-1.3 mm diameter, glabrous; bark dark gray, smooth. Leaves opposite, persistent; bud scales persistent; blades medium gray, cordiform, 3-4 3 2-3 cm, coriaceous, glabrous, domatia absent, base acute, margin slightly revolute, apex obcordate, midrib slightly sunken above, raised below, secondary veins barely visible, 5-6 per side, 5-7 mm apart, looping 1.5-2 mm from the margin; petiole medium gray, 4 3 1.2-1.6 mm, entirely woody, glabrous. Flowers unseen, but fruits solitary. Fruiting pedicel 7-8 3 1-1.2 mm; young fruits green, reddish when mature, ovoid, 12.2-12.6 3 7.4-7.8 mm, smooth, sometimes covered with a white pellicle, apex apiculate, with the persistent style; dry pericarp 0.4 mm thick; endocarp woody.

Etymology

The specific epithet refers to the inverted heart-shaped leaf blade, with its distinctive obcordate apex.

Distribution, ecology and phenology

Noronhia obcordifolia occurs in low-elevation dry forests on limestones on Montagne des Français in the north ( Fig. 36). It has been collected in fruits in August.

Conservation status

Noronhia obcordifolia is known only from three collections from the newly established protected area of Montagne des Français. Because of its close proximity to the city of Diégo-Suarez, the forest on Montagne des Français has played an important role in supplying the population with charcoal and other products, providing refuge to fugitive criminals, and favoring other illegal activities such as small-scale cannabis cultivation. This rocky outcrop has also become a favorite destination for rock climbers in recent years. Although its new status as a protected area should gradually reduce the impacts of these threats, habitat degradation as well as habitat alteration resulting from illicit exploitation and invasive species will likely persist. Therefore, N. obcordifolia is assigned a preliminary status of “Critically Endangered” [CR B2ab(iii,v)].

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Notes

Noronhia obcordifolia most closely resembles N. lowryi , from which it differs by its smooth (vs. rugose) bark, woody (vs. non-woody) petioles, cordiform (vs. elliptic) leaf blades, and ovoid (vs. pyriform) fruits with an apiculate (vs. flat) apex. Distinctive features include coriaceous, inverted heart-shaped leaves with an obcordate apex, and apiculate fruits somewhat covered with a white pellicle.

Paratypi

MADAGASCAR. Prov. Antsiranana: Ramena, Andavakoera , 12°19’41”S 49°20’26”E, 76 m, 3.VIII.2007, Hong-Wa et al. 524 ( CNARP, MO, P, TAN); ibid. loc., 12°19’57”S 49°21’19”E, 172 m, 4.VIII.2007, Hong-Wa et al. 544 ( TAN) .