Virola megacarpa A. H. Gentry.

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

9. Virola megacarpa A. H. Gentry. Fig. 20A, B

Virola megacarpa A. H. Gentry. Ann. Missouri Bot. Gard. 62(2): 474. 1975. Type. Panama. Colón: Santa Rita Ridge, 23 Mar 1972 [fr], [A. H.] Gentry & [J. D.] Dwyer 4804 (holotype: MO!; isotypes: BM!*, MEXU!*, WIS!*).

Distinctive characters.

Virola megacarpa can be recognised by its large and oblong leaf blades (20.3-37 × 7-13 cm) with numerous [(32-) 40-50 per side], dense lateral veins and a densely pubescent abaxial surface with dark brown to ferruginous dendritic trichomes ( Fig. 3I ). It is also the species with the largest fruits (4-5.7 × 2-2.9 cm) in the region and likely the genus; these are also densely pubescent with an acuminate to rostrate apex ( Fig. 4P ) and thick pericarp (3-6 mm).

Distribution.

Virola megacarpa is only known from Panama ( Colón, Panamá, San Blas and Veraguas) ( Fig. 18C ) from 50-550 m elevation.

This species is attributed to Colombia in Cogollo (2011), based on the specimen J. Brand 1252 (JAUM!*; fr). It is also mentioned as occurring in Colombia in Gradstein (2016) and Ulloa Ulloa et al. (2017), though these references do not mention a voucher specimen (likely they refer back to the same specimen cited by Cogollo [2011]). The first author has seen a digital image of this specimen (J. Brand 1252, JAUM) and it appears that the leaf undersurface and fruits are scarcely pubescent, as well as smaller. This specimen clearly corresponds to a species of the group Surinamenses sensu Smith and Wodehouse (1938) and not V. megacarpa . For that reason, V. megacarpa is considered restricted to Mesoamerica.

Common names.

None recorded.

Phenology.

The only observed herbarium specimen with flowers (these staminate) was collected in August. Fruits were collected in February and March and August to November.

Field characters.

Plants are trees 12-30 m tall and 21.5-53 cm DBH. Damaged bark releases exudate that is red or that oxidises reddish-brown. Flowers have pale yellow perianth. Fruits are densely pubescent with brown trichomes and a red aril.

Discussion.

Vegetatively, Virola megacarpa can be confused with V. koschnyi and some specimens have been identified as the latter (e.g. G. de Nevers & H. Herrera 7917, MO). Both species share leaf blades with numerous and conspicuous lateral veins and pediculate trichomes on the abaxial surface. However, V. megacarpa has more lateral veins per side [(32-) 40-50 vs. (16-) 20-35] and these are more closely spaced ( Figs 8G and I ) and fruits are larger (4-5.7 × 2-2.9 cm vs. 1.9-3.1 × 1.5-1.9 cm) ( Fig. 4F, P ).

Specimens examined.

Panama. Colón: East of Portobelo, 50-100 m elev., 12 Oct 1992 (fr), G. McPherson & M. Richardson 15873 (MO!); Teck Cominco Petaquilla mining concession, 220 m elev., 20 Feb 2008 (fr), G. McPherson & M. Merello 20081 (MO!); East ridge, no elev., 23 Feb 1968 (fr), J. A. Duke 15261 (MEXU!*, MO!). Panamá: [Chepo] El Llano-Cartí road, 5 km N of Pan-American Highway at El Llano, 300 m elev., 10-11 Nov 1973 (imm fr), M. Nee 7920 (MEXU!*, MO!); El Llano-Cartí road, 16-18.5 km by road N of PanAmerican Hwy, at El Llano, 400-450 m elev., 28 Mar 1974 (fr), M. Nee & E. Tyson 10983 (CR!, F!*, INPA!*, MO-2 sheets!). San Blas: El Llano-Cartí Road, Km 19.1, 350 m elev., 19 Mar 1985 (fr), G. de Nevers 5184 (INPA!*, MEXU!*, MO!). Veraguas: Santa Fe, Valley of Río Dos Bocas along road between Escuela Agricola Alto Piedra and Calovebora, 450-550 m elev., 31 Aug 1974 (♂ fl), T. B. Croat 27785 (INPA!*, 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 8. Pattern of the lateral veins in Mesoamerican Virola A Virola allenii (K. Thomsen 1284, NO) B V. amistadensis (G. McPherson 8703, MO) C V. chrysocarpa (B. Hammel et al. 16864, MO) D V. elongata (M. Correa & R. L. Dressler 1078, MO) E V. fosteri (G. de Nevers 7226, MO) F V. guatemalensis (G. Ibarra 957, MO) G V. koschnyi (J. Miller & J. C. Sandino 1110, MO) H V. laevigata (N. Zamora & T. D. Pennington 1583, MO) I V. megacarpa (G. de Nevers 5184, MO) J V. montana (E. Lepiz & J. F. Morales 284, MO) K V. multiflora (J. Manzanares 3561, MO) L V. nobilis from Barro Colorado (R. J. Schmalzel 320, MO) M V. otobifolia (G. de Nevers et al. 7530, MO) N V. sebifera (T. B. Croat 5959, MO) O V. nobilis from Osa Peninsula (R. Aguilar 11186, MO).

Figure 18. Geographic distribution of Virola koschnyi (A), V. laevigata (B), V. megacarpa (C), V. montana (D), V. multiflora (E) and V. nobilis (F).

Figure 20. A. Virola megacarpa A branch with fruits, both leaf blade surfaces shown B fruit. Virola nobilis from Barro Colorado C lower trunk and buttress D branch with fruits, leaf blades on both surfaces E pistillate flowers F staminate flower and bud G fruits. Photos by Carmen Galdames (A, B), Rolando Perez (C, D, G), Steven Paton (E, F); all photos from https: // stricollections. org / portal / index. php.