Virola fosteri D.Santam., 2019

Santamaria-Aguilar, Daniel, Aguilar, Reinaldo & Lagomarsino, Laura P., 2019, A taxonomic synopsis of Virola (Myristicaceae) in Mesoamerica, including six new species, PhytoKeys 134, pp. 1-82 : 1

5. Virola fosteri D.Santam. sp. nov. Figs 15 , 16

Diagnosis.

Species resembling Virola multiflora due its small leaf blades and fruits, similar leaf shape and inconspicuous stellate, sessile trichomes on the abaxial leaf surface. Both species also occur on the Caribbean slope of Mesoamerica. They differ in the shape of the leaf base (revolute in V. fosteri vs. not revolute in V. multiflora ), the length of the filament column (0.9-1.3 mm vs. 0.7-1 mm long) and anthers (0.6-0.9 mm vs. 0.3-0.6 mm long) and thickness of the pericarp (1.5-2.5 mm vs. 0.7-1 mm thick).

Type.

Panama. Bocas del Toro: Isla Colón, Aprox. a 8 km al NE de los laboratorios del Instituto Smithsonian de Investigaciones Tropicales, Big Creek, 5 m elev., 23 Apr 2009 (♂ fl), C. Galdames, M. Stapf, K. Toribio & Arsenio 6422 (holotype: PMA!* [094201, PMA92162]; isotypes: MO! [6421737, MO-2504180], SCZ!* [17752, SCZ17684]).

Description.

Tree (15-) 20-35 m × 35-60 cm DBH; bark brown or reddish. Exudate described as watery-reddish possibly from the bark, damage to any part of the plant causes the flow of a watery exudate that turns reddish moments later. Twigs 0.12-0.24 cm thick, terete to slightly angulate, puberulent, trichomes stellate, yellowish to pale brown. Leaves: petiole 0.4-0.7 (-1) × 0.07-0.12 cm, canaliculate, densely tomentose to sparsely pubescent, the trichomes stellate; leaf blades 7.8-12 × 1.4-2.7 cm, narrowly elliptical or oblong to oblanceolate; adaxial surface dark brown, light brown or blackish when dry, glabrous, the surface smooth; abaxial surface pale brown to reddish-brown when dry, puberulent, trichomes stellate, sessile, yellowish to pale brown, with 4-8 branches, each branch ± 0.03-0.05 mm long, persistent; lateral veins 16-24 per side, 10-15 veins per 5 cm, 0.2-0.5 (-0.7) cm apart, the same colour as the adaxial surface, on adaxial surface sunken, on abaxial surface flat to slightly elevated, arcuate-ascending, slightly anastomosing near the margin and not forming a marked intramarginal vein; tertiary veins adaxially almost indistinct to slightly sunken, abaxially almost indistinct; midvein adaxially canaliculate, glabrous, abaxially raised, laterally compressed and sometimes resembling a cutting edge, tomentose to sparsely pubescent; base attenuate, revolute; margin revolute (especially near the base) or flat; apex acute to acuminate. Staminate inflorescences 2.5-5.3 cm long, axillary, usually in the axil of terminal leaves, axes flattened to irregularly angled, tomentose, with trichomes stellate, yellowish to pale brown; peduncle 0.9-17 × 0.13-0.25 cm; bracts 2-5 × ca. 2.5 mm, tomentose on both surfaces, the indumentum more clustered on the external side, caducous; terminal fascicles dense, with 5-15+ flowers. Staminate flower with the pedicel 1-2 mm long; receptacle 1.5-2.3 mm wide; perianth 2-2.5 (-3) mm long, subglobose, yellow, orange or yellow-orange when fresh, connate for 0.5-0.8 mm of length, abaxial pubescent, with golden to yellowish trichomes, adaxial surface glabrous somewhat pubescent near the lobes; lobes 3, 1.5-2.6 × (0.6-) 1.3-1.8 mm; stamens 3 (-6), the filament column 0.9-1.3 mm long, glabrous, straight or rarely thickened near the base in some flowers (McPherson 20148), thin, not constricted at the apex; anthers 0.6-0.9 mm long; apiculus small enough to as appear absent, acute to obtuse. Pistillate inflorescences 1.3-3.9 cm long, axillary, with trichomes on the axes similar to those of the staminate inflorescences; peduncle 0.7-2.2 × 0.08-0.14 cm; bracts not seen; terminal fascicles of 4-7 flowers. Pistillate flowers with the pedicel 1.5-2.5 mm long; perianth 2-3 mm long, subglobose, yellow when fresh, connate by 0.6-0.8 mm long, abaxial surface pubescent with golden to yellowish trichomes, adaxial surface sparsely pubescent, the indumentum on the lobes; lobes 3, 1.2-1.5 (-2.5) × 0.7-2.1 mm; gynoecium 1.6-2.4 × 1.1-1.4 mm, densely pubescent, globose to subglobose, stipitate; stigmatic lobes ca. 0.6 mm, erect. Infructescence 2.5-3 cm long, with 1-3 fruits, peduncle 1.5-1.7 × 0.15-0.38 cm. Fruits 1.5-2.3 × 1.2-1.8 cm, ovoid, sessile or very shortly stipitate, tomentose, the trichomes stellate, reddish-brown, the surface rugose when dry, the line of dehiscence canaliculate or smooth, the base obtuse to rounded, the apex obtuse, yellow, orange or golden brown when fresh; pericarp 1.5-2.5 mm thick; pedicel 0.4-0.5 cm long; seed ca. 1.6 × 0.9 cm, the testa pale brown when dry, very slightly grooved; aril usually described as red when fresh, reddish-brown when dry, coriaceous, oily, somewhat thick, laciniate in narrow bands. Germination epigeal, seedling cryptocotylar, epicotyl hairy, moderately dense, stellate and sessile ( Garwood 2009; as V. multiflora ).

Distinctive characters.

Virola fosteri is recognised by its small leaf blades (7.8-12 × 1.4-2.7 cm) and fruits (1.5-2.3 × 1.2-1.8 cm) ( Figs 4I and 16 F–H ), as well the stellate, sessile trichomes on the abaxial surface of the leaf ( Fig. 3E ). It is also distinguished by its leaf blades that have numerous lateral veins (16-24 per side) that are prominent on adaxial surface, the revolute leaf margin and the base ( Fig. 16C ), the midvein that is laterally compressed adaxially and sometimes resembling a cutting edge; staminate flowers with a filament column (0.9-1.3 mm long) that is longer than the anthers (0.6-0.9 mm long); and its thick pericarp (1.5-2.5 mm).

Etymology.

The specific epithet honours one of its collectors, Robin B. Foster (1945-), ecologist and botanist at Field Museum in Chicago (F) who pioneered the cataloguing of the flora of Barro Colorado Island (BCI) in Panama, where V. fosteri occurs. Robin noted on one of his collections (R. B. Foster 2931) that it could represent a new species. In addition, on the same herbarium sheet, he observed one of the taxonomic characters that we here use to distinguish this as a new species: " Leaves are consistently small throughout the tree and on juvenile plants."

Distribution.

Virola fosteri is known from Costa Rica ( Limón) and Panama (Bocas del Toro, Colón, Panamá, San Blas and Veraguas) ( Fig. 9E ). It is found on the Caribbean slope from 0-350 (-800) m elevation.

Preliminary conservation status.

Virola fosteri is Vulnerable following IUCN criterion B2a. While the EOO for this species is large (25,645 km2), the small AOO (40 km2) with only eight known localities warrants its conservative status.

Common names.

Panama: bogamani, fruta dorada.

Phenology.

Flowering of Virola fosteri has been recorded in January to April, June and October and production of fruits in January to April.

Field characters.

Plants are large trees with tall buttresses. Bark exudes reddish watery exudate when damaged. Their small leaves are white or grey below. Flowers have pale orange or yellow perianth. The mature fruit is yellowish or golden brown with a red aril and brown seed.

Discussion.

In addition to the characteristics presented in diagnosis, Virola fosteri tends to have a higher number of and sunken (vs. plane) lateral veins per side than V. multiflora (16-24 vs. 10-18 per side), denser trichomes with longer branches on the abaxial leaf surface ( Fig. 3E, K ) and larger fruits [1.5-2.3 × 1.2-1.8 cm vs. 1.3-1.9 × 0.9-1.2 (-1.4) cm] ( Fig. 4I, J ).

It is also comparable to V. micrantha A. C. Sm. from Colombia due to the similar size of the leaf blades, which also have sessile stellate trichomes on the abaxial surface and short staminate inflorescences. Virola micrantha is a name apparently ignored in recent publications ( ter Steege et al. 2016, 2019; Ulloa Ulloa et al. 2017; Gradstein 2016). Until recently, V. micrantha was only known from the type specimen (R. E. Schultes & G. A. Black 46-377, US*); however, via a herbarium study at MO, we identified additional Colombian material with staminate flowers (R. Jaramillo et al. 7846, MO-2 sheets!) and can also extend its distribution to Venezuela (E. Marín 571 [MO!], R. L. Liesner 6778 [MO!] and J. Velazco 851 [MO!]). Virola fosteri differs from this species by its attenuate leaf base and acute to acuminate apex (vs. obtuse on both sides, also mucronulate at the apex), longer perianth of staminate flowers (2-2.5 [-3] mm vs. ca. 1 mm long) and longer anthers (0.6-0.9 mm vs. ca. 0.3 mm long) ( Smith 1953).

Virola coelhoi W. A. Rodrigues (Colombia; S. Defler 411, MO!. Peru; C. Grández & N. Jaramillo 2787, MO!) from Brazil, and V. parvifolia Ducke (Brazil) are other species with similarly-sized leaves with revolute margins, traits shared with V. fosteri . Additionally, with V. coelhoi , which it is more likely to be confused, V. fosteri shares overall leaf shape and the type of trichomes on the abaxial surface (i.e. stellate, sessile and yellowish). The new species is distinguished from V. coelhoi by the abaxial surface that is pale brown to reddish-brown when dry and puberulent (vs. abaxial surface yellowish, very densely pubescent), staminate inflorescences with small bracts (2-5 × ca. 2.5 mm vs. 2.5-9 × 4-6 mm), and staminate flowers with longer filament columns [0.9-1.3 mm vs. (0.3-) 0.6-0.7 long] and anthers (0.6-0.9 mm vs. 0.4-0.5 mm long). It can be differentiated from V. parvifolia by its leaf blades and inflorescences that are glabrous or nearly so (vs. pubescent in V. fosteri ) ( Ducke 1936); additionally, Ducke (1936) mentions that V. parvifolia has numerous small granules or tubercles on the branches, leaf blades and peduncles that are lacking in V. fosteri .

Jiménez (2007; as Virola sp. B) mentions that the new species is similar to Virola pavonis (A. DC.) A. C. Sm. from South America. This is probably because both species have sessile and stellate trichomes on the abaxial surface of the leaf, sometimes a similar leaf size, a similar number of lateral veins (though there is a tendency towards higher numbers of veins in V. pavonis ) and the length of the filament column and anthers. However, the new species differs in its shorter staminate inflorescences [2.5-5.3 cm vs. (3-) 7-15 cm long], smaller fruits (1.5-2.3 × 1.2-1.8 cm vs. 2.5-5 × 1.5-2.5 cm) and in the canaliculate or smooth line of dehiscence (vs. carinate).

In Mesoamerica, other species with leaf blades that are covered with stellate and sessile trichomes on the abaxial surface ( Fig. 3E, F, L ) and a filament column that is longer than the anthers are V. guatemalensis and V. nobilis . However, these two species have larger leaf blades (12.3-17.2 [-27.5] cm vs. 7.8-12 cm long) and fruits ([2.1-] 2.3-2.7 [-3.1] cm vs. 1.5-2.3 cm long). Similarities with V. nobilis , specifically, include their distribution pattern (at least in Panama), leaf blades with more lateral veins per side (20-30 [25-32] vs. 16-24) that are markedly elevated abaxially (vs. flat to slightly elevated), the leaf margin and base that are usually not revolute (vs. revolute) and fruits that generally have thick pericarp (2.5-3.5 mm vs. 1.5-2.5 mm).

Notes.

The species referred to as Virola sp. B in the Manual de Plantas de Costa Rica ( Jiménez 2007) and as V. multiflora (G. de Nevers 7608, MO!) in the Catálogo de las plantas vasculares de Panamá ( Correa et al. 2004) correspond to V. fosteri .

Specimens examined.

Costa Rica. Limón: Talamanca. San Miguel, Asacode, sendero a San Miguel, 30-100 m elev., 18 Jan 1997 (♂ fl), J. González et al. 1632 (CR!, MEXU!*, MO!); Lomas Mreduk (La Pera), antiguo campo de exploración petrolera, 300-350 m elev., 06 Oct 2002 (fl), J. Gómez-Laurito et al. 13903 (USJ!); cerros al sur del camino entre Puerto Viejo y Manzanillo por un camino nuevo hacia Bribri, 100 m elev., 18 Jan 1992 (fr), B. Hammel 18392 (CR-2 sheets!, MEXU!*, MO!). Panama. Bocas del Toro: Parcela ubicada a 10 km de la desembocadura de la quebrada Boca Chica en la margen izquierda del río Changuinola, 550 m elev., 23 Oct 2007 (fl), R. Aizprúa et al. 3398-RA (PMA!*, US!*); ibid, 23 Oct 2007 (fl), N. Daguerre et al. 660-ND (PMA!*); along road to Chiriquí Grande, ca. 1.5 miles along side road east of highway, 250-300 m elev., 24 Jun 1986 (♂ fl), G. McPherson & B Allen 9646 (MO!). Colón: San Lorenzo, no elev., 15 Jun 2009 (fr), J. Lezcano & E. Spear 593 (PMA!*); Donoso, Teck Cominco Petaquilla mining concession, 300 m elev., 22 Feb 2008 (♂ fl), G. McPherson & M. Merello 20148 (MO!, PMA!*); Donoso, westernmost part of province, site of proposed copper mine (INMET), 150 m elev., 12 Apr 2009 (imm fr), G. McPherson 20913 (MO!, PMA!*); camino viejo de Piñas-Sherman, no elev., 22 Sep 2013 (fl), R. Pérez et al. 1130 (MO n.v., PMA!*, SCZ!*). Panamá: Zona del Canal, Barro Colorado Island, slope between AVA 7 and FD 5, [10-100 m elev.], 30 Mar 1979 (fr), R. B. Foster 2931 (MO!, PMA!*); Barro Colorado Island, Wetmore trail, [10-100 m elev.], n.d. 1980 (♂ fl), R. B. Foster 2946 (CR!, F!*, MO!, PMA!*, U!*, US!*); Barro Colorado Island, Drayton, Drayton 18-19, [10-100 m elev.], 31 Mar 1988 (fr), N. Garwood 2301A (PMA!*). San Blas: El Llano Cartí road, km 26.5, no elev. 10 Apr 1985 (fr), G. de Nevers et al. 5285 (INPA!*, MEXU!*, MO!, PMA!*); El Llano-Cartí road, km 32.3, 200 m elev., 02 Mar 1986 (♀ fl, imm fr), G. de Nevers 7226 (INPA!*, MO!, PMA!*); Cangandi, 30 m elev., 27 Mar 1986 (♀ fl, imm fr), G. de Nevers et al. 7608 (MO!). Veraguas: Santa Fe, near the entrance to the agriculture school, Alto de Piedra, [800 m elev.], 26 Feb 1975 (fr), S. Mori & J. Kallunki 4891 (MO!).

Figures

Figure 3. Trichomes in Mesoamerican Virola A Virola allenii (R. Aguilar 2224, MO) B V. amistadensis (G. McPherson 8703, MO) C V. chrysocarpa (O. Valverde 970, MO) D V. elongata (G. McPherson 13674, MO) E V. fosteri (G. McPherson 20913, MO) F V. guatemalensis (R. Cedillo 3349, MO) G V. koschnyi (R. E. Gereau et al. 3455, MO) H V. laevigata (R. Aguilar 2004, MO) I V. megacarpa (J. A. Duke 15261, MO) J V. montana (E. Bello 855, MO) K V. multiflora (R. Rueda et al. 8196, MO; inset, J. C. Sandino 3302, MO) L V. nobilis from Barro Colorado (R. J. Schmalzel 320, MO) M V. otobifolia (G. de Nevers & H. Herrera 7056, MO) N V. sebifera (F. Almeda et al. 5553, MO) O V. nobilis from Osa Peninsula (R. Aguilar 11186, MO).

Figure 4. Fruits of Mesoameican Virola, organised in groups of morphologically similar species A V. allenii (P. H. Allen 6727, GH) B V. amistadensis (G. McPherson 9715, MO) C V. otobifolia (A. Gentry & S. Mori 14199, MO) D V. macrocarpa (A. E. Lawrance 675, MO) E V. chrysocarpa (B. Hammel et al. 16864, MO) F V. koschnyi (R. Robles 1587, MO) G V. guatemalensis (S. Sinaca 1542, MO) H V. montana (J. Utley & K. Utley 5054, MO) I V. fosteri (S. Mori & J. Kallunki 4891, MO) J V. multiflora (R. Rueda et a. l 9960, MO) K V. sebifera (T. B. Croat 5959, MO) L V. elongata (J. D. Dwyer & M. Correa 8420, MO) M V. laevigata (R. Aguilar 1585, MO) N V. nobilis from Barro Colorado (T. B. Croat 8090, MO) O V. nobilis from the Osa Peninsula (G. Herrera 4222, MO) P V. megacarpa (G. de Nevers 5184, MO). Scale bars: 1 cm.

Figure 9. Geographic distribution of Virola allenii (A), V. amistadensis (B), V. chrysocarpa (C), V. elongata (D), V. fosteri (E) and V. guatemalensis (F).

Figure 15. Virola fosteri A branch with leaves and inflorescences B partial inflorescences C fruit D seed with aril E seed. Drawn by Pedro Juarez, based on C. Galdames et al. 6422 (A-E).

Figure 16. Virola fosteri A lower trunk and buttresses B branch with staminate inflorescences C leaf blades showing adaxial (left) and abaxial (right) surface; also demonstrating the revolute base D branch with staminate inflorescences and leaf blades on abaxial surface E close up of staminate inflorescences F fruit G aril covering the seed H seed Photos by Rolando Perez (A), Carmen Galdames (B, D, E), Steven Paton (C, F, G, H); all photos from https: // stricollections. org / portal / index. php.