Philodendron wilburii Croat & Grayum var. wilburii
Usually hemiepiphytic, sometimes terrestrial; cataphylls 13--26 cm long, unribbed to bluntly 1-ribbed; petioles 16--46 cm long, obtusely flattened adaxially; blades ovate-triangular, cordate to saggitate at base, 17--36 (averaging 26) cm long, 11--27 (averaging 16) cm wide (1.3--2 times longer than wide, averaging 1.5 times), (1.3--2 times longer than petiole); sinus usually hippocrepiform, sometimes shallowly parabolic.
INFLORESCENCE 1--3(4) per axil; peduncle 3.5--14 cm long; spathe 7.5--13.5 cm long; spadix 9--11 cm long; pistillate portion (2.5)3.4--4.3 cm long.
Flowering in Philodendron wilburii var. wilburii appears to have a bimodal pattern, with the main event occurring in the late dry season to the mid-rainy season (March through September but especially April through August). The second flowering event occurs in the early dry season, especially in January. A flowering collection from November is unusual. Post-anthesis collections also occur in two clusters, June through September and November through February. Mature fruits have been collected only in March.
Philodendron wilburii var. wilburii is largely known from central Costa Rica to an area of the frontier with Panama but rarely also to Central Panama (Veraguas), extending from 400 to 2000 m, mostly at over 1000 m elevation. It is largely known from Central Costa Rica, mostly at elevations of higher than 1000 m in premontane rain, lower montane wet, and lower montane rain forests. It has been collected mostly in the Cordillera de Tilarán, especially in the San Ramón region and in the Monteverde Reserve at 1350 to 1700 m (averaging at more than 1500 m) but to a lesser extent in areas to the east and west of the Central Valley. It has been collected only rarely in the Cordilleras de Guanacaste and Talamanca.
One collection believed to be this species, Croat 76799, is from Veraguas Province near Santa Fe in Premontane moist forest. Because of the isolated nature of this population it may prove to represent a distinct taxon. The plants are unusual in having unribbed to bluntly 1-ribbed cataphylls, thin, ovate to ovate-triangular, cordate, mostly greenish drying blades and peduncles 3.5 to 14 cm long (averaging 9.3 cm long), usually equaling or shorter than the spathe.
Philodendron wilburii var. wilburii might be confused with a lowland form of P. wilburii var. longipedunculatum from southeastern Costa Rica that has leaf blades more nearly as broad as long (e.g. Grayum 4759). Especially confusing are Grayum 4759 and 9167 from Puntarenas Province in the region of the Osa Peninsula at 300 to 400 m elevation. Both look much like P. wilburii var. wilburii, and if they prove to represent that taxon, they would be the only collections from such a low elevation and the only collections from southwestern Costa Rica.
Another noteworthy collection is Croat 61199, a sterile collection that had its locule and ovary number determined from a field-collected infructescence. This collection, from Monteverde in Puntarenas Province, Costa Rica, has ovaries with only 5 locules but 10--14 ovules per locule. It otherwise matches typical P. wilburii. Perhaps it represents a different species.
A collection from the Azuero Peninsula in Panama is somewhat intermediate between P. wilburii var. wilburii and P. wilburii var. longipedunculatum. Though it has very long peduncles like P. wilburii var. longipedunculatum, its blades dry somewhat blackened with the posterior lobes somewhat more rounded than normal for P. wilburii var. longipedunculatum.
Additional specimens examined for P. wilburii var. wilburii:
COSTA RICA. Alajuela: San Ramón, N of Los Angeles, ca. 1200 m, Primack et al. 236 (DUKE); between Los Angeles and ca. 4 km beyond Río Balsa, 1100--1200 m, Utley 366 (DUKE); San Ramón--Bajo Rodriguez, 940 m, Croat 78833 (CR, INB, MO); 1025--1100 m, 78885 (CR, INB, MO); San Ramón--Cataratas, km 11, 850 m, Pennington 11543 (K); Cantón Alfaro Ruiz, Guadalupe, 1450 m, A. Smith 2844 (F); San Luis de Zarcero, 1575 m, A. Smith NY1023 (F, NY); 12 km NNW of San Ramón, 1100 m, 10E10'N, 84E29'W, Liesner & Judziewicz 14913 (CR, MO, WIS); 15 km NNW of San Ramón by road, 2.5 km N of Balsa on road to San Lorenzo, 1050--1100 m, 10E11'N, 84E30'W, Liesner & Judziewicz 14753 (MO); 17--20 km NNW of San Ramón, ca. 750 m, 10E13'N, 84E32'W, 14690 (MO, WIS); 1 km S of Balsa de San Ramón, 1200 m, 10E13'N, 84E31'W, Lent 3514 (F, MO); 9 km SE of Ramón, 1000 m, 10E16'N, 84E05'W, Loiselle 177 (MO); 11.2 kms N of Zarcero, 1400 m, 10E12'N, 84E23'W, Hoover 1351 (CR, MO); 5.7 mi. N of San Ramón, 1200 m, Croat 46836 (MO); ca. 1.3 mi. N of Angeles Norte, ca. 1200 m, Croat 46874 (MO); Finca Los Ensayos, ca. 11 mi. NW of Zarcero, Croat 43634 (CM, MO); San Ramón--Balsa, ca. 5.7 km N of bridge over Quebrada Volio, 1100--1150 m, ca. 10E08'N, 84E29'W, Stevens 14182 (CAS, MO); 2.3 km N, Río Balsa, ca. 1050--1150 m, 10E01'N, 84E30'W, Stevens 14198 (K, MO); Reserva Forestal de San Ramón, ca. 10 km W of Laguitos, Río San Lorencito, 850--1100 m, 10E18'N, 84E34'W, Hammel et al. 15252 (MO); 800--1000 m, 10E12'53"N, 84E36'28"W, Herrera & Mora 179 (MO); Río San Pedro, Cerro Azahar, 15 km NW of San Ramón by air, 1400--1500 m, 10E09'30"N, 84E34--35'W, Liesner et al. 15486 (MO), 15487 (CR, MO, NY, WIS); UCR Reserva, Fila Volcán Muerte, 1000--1300 m, 84E32'W, 10E12'N, Barringer & Gómez-Laurito 2559 (F), Barringer & Pérez 3784 (CR, F); Monteverde Reserve, Dryer 794 (MO), 997 (F); 1500--1600 m, 10E17'N, 84E47'W, Haber et al. 10069 (CR, MO, MV); 10E18'N, 84E47'W, Grayum & Sleeper 3851 (CR, MO). Cartago: Moravia-Quebrada Platanillo, ca. 1250 m, Croat 36658 (MO); SE of Turrialba, ca. 3 km NE of La Suiza, ca. 1200 m, Lellinger & White 1403 (US); Tapantí Reserve, Nilsson 195 (CR), 215 (CR), 220 (CR), 238 (CR), 254 (CR), 266 (CR), 367 (CR), 647 (CR); 1250--1350 m, Ferreyra 15702 (USM); 1500--1800 m, 9E43'N, 83E47'W, Grayum & French 5827 (INB, MO); ca. 1350 m, 9E47'N, 83E48'W, Grayum & Sleeper 3694 (MO, US); Utley & Utley 5613 (DUKE); 1500--1800 m, 9E43'N, 83E47'W, Croat & Grayum 68292 (CR, MO, US); Croat 36122 (MO); ca. 6 km S of Cartago by air, Quebrada Cangreja, 3 km S of Pan-American Highway, 1620--1650 m, 9E46'N, 83E57'W, Liesner & Judziewicz 14474 (MO); Alto Patillos, 4 km S of Tapantí, 1480 m, Lent 1240 (F); Río Grande de Orosi, ca. 15 km S of Tapantí, 1500 m, 9E42'N, 83E47'W, Burger & Liesner 6752 (F, NY); La Sierra, 6 km NE of Empalme, 2000 m, Gómez 19762 (MO); Santa Teresa--Río Coliblanco, 6--7 km NE of Pacayas, ca. 1700 m, Luteyn 3246 (DUKE, MO); Quebrada Honda--Río Sombrero, ca. 1--2 km above El Muñeco, ca. 1400 m, 3236 (DUKE, MO); 31 km from San José, SE on CR-2, 1750 m, Harmon 6105 (UMO); Río Grande de Orosi valley, near Río Villegas, 1700 m, Lent 1860 (F); Río Macho, Nilsson 242 (CR), 274 (CR), 312 (CR). Guanacaste. Tilarán, Z.P. Tenorio, 1050 m, G. Rodríguez 24 (CR). Heredia: Río Peje--Río Sardinalito, Volcán Barva, 700--950 m, 10E17'30"N, 84E04'30"W, Grayum 6929 (MO); Río La Paz Grande, 7.5 km N of Vara Blanca, 1270--1350 m, Croat 36051 (MO); La Selva Field Station, Valerio s.n. (USJ). Limón: Kámuk massif, between Río Tararia and NE Kámuk páramo, 1900--2300 m, 9E14-15'N, 82E59'W, Davidse & Herrera 29203 (CR, MO). Puntarenas: Monteverde Reserve, ca. 1350 m, Croat 47139 (MO); 2 km SW Station, 1500--1550 m, Ingram & Ferrell-Ingram 1734 (MO); ca. 3.5 km NE of Monteverde Reserve, ca. 1500 m, Wilbur et al. 15816 (MO); Kennedy 545 (F); Haber 2369 (MO); Pounds 321 (MO); 449 (MO); Gentry et al. 48860 (CR, MO, NY); Haber 3880 (MO); Haber & Bello 2458 (MO); Bello & Cruz 5237 (CR, INB); Croat 61199 (MO); Feinsinger et al. 83-66-1 (FLAS); Burger & Baker 9649 (F, MO, SEL); Palmar Norte--Jalisco, 300--400 m, 8E58'30"N, 83E28'W, Grayum et al. 9167 (MO). San José: Bajo La Hondura, Paracito--Río Claro, 1100--1400 m, Croat 44494 (F, MO); above Río Hondura, at Baja La Hondura, 1150 m, Taylor 17933 (NY); Cerro de la Muerte, along CA-2, N of turnoff for road 222, ca. 2000 m, Croat 32851 (MO); ca. 15 km S of San Isidro de Cartago, 1880 m, Utley & Utley 2948 (F); La Palma, ca. 1600 m, Standley 38300 (US); La Palma area, 1400 m, 10E12'N, 84E10W, Burger & Liesner 6212 (CR, F, MO); ca. 6 km NE of San Jerónimo, Primack et al. 322 (DUKE); Braulio Carrillo National Park, 1000--1500 m, 10E05'N, 83E57'W, Croat 61227 (CM, MO); Río Patria--Río Zurquí, Cerro Hondura, 1500--1600 m, 10E04'N, 84E01'W, Grayum & Sleeper 6116 (CR, MO); Puriscal, Z.P. La Cangreja, 500 m, Morales 924 (CR, INB). PANAMA. Veraguas: vic. Santa Fe, along road between Santa Fe and Alto Piedra, 1.7 mi. N of Hotel Santa Fe, 470 m, 8E31'N, 81E05'W, Croat & Zhu 76799 (B, CAS, CR, F, HMNM, K, MO, NY, PMA, SCZ, US).