Planta plerumque hemiepiphytica; caulis scandens; internodia 3--15 cm longa, 1.3--2 cm diam.; cataphylla 7--26 cm longa, incostata vel obtuse 1-costata, decidua; petiolus subteres vel teres, moderate spongiosus, obtuse complanatus adaxialiter, 16--55 cm longus, 5--12 mm diam.; lamina ovato-triangularis, 17--36 cm longa, 11--31 cm lata, cordata vel sagittata basi; inflorescentia 1--3(4); pedunculus 3.5--29 cm longus, 8--12 mm diam.; spatha 7.5--18 cm longa; lamina spatha extus albida vel pallide viridi aut cremeo-flava, intus albida (sub anthesi) vel cremeo-flava; tubo spathae extus virenti, intus rubella vel atrimarronino; pistilla (5)6--7-loculari; loculi 1--2-ovulati; baccae pallide vel vivide aurantiacae.

Usually hemiepiphytic, sometimes terrestrial; stem scandent, semiglossy, sap watery, spicy-scented, sometimes milky-white; internodes usually long, glossy to semiglossy, 3--15 cm long, 1.3--2 cm diam., usually longer than broad, dark green to gray-green, sometimes drying black, epidermis often cracking or minutely fissured, brittle, sometimes silver-gray; cataphylls soft, 7--26 cm long, unribbed to bluntly or sharply 1-ribbed, sometimes sharply D-shaped and sharply 2-ribbed, whitish or green, fleshy, glossy, deciduous; petioles 16--55 cm long, 5--12 mm diam., subterete to terete, moderately spongy or moderately firm, bluntly D-shaped or obtusely flattened adaxially, surface weakly glossy to semiglossy, smooth; sheathing 6--8 cm long; blades ovate-triangular, thinly coriaceous to subcoriaceous, matte to semiglossy, weakly to moderately bicolorous, acuminate to long-acuminate at apex (the acumen more or less inrolled), cordate to sagittate at base, 17--36 cm long (averaging 26 cm), 11--31 cm wide, more or less equal in length to or longer than petiole, margins hyaline, upper surface drying brownish, dark brown, or gray-brown to green, lower surface drying light brownish green to reddish brown or yellowish brown; anterior lobe 11.5--32 cm long, 7--24 cm wide; posterior lobes somewhat spreading, rounded to obtuse, 4--14 cm long, (2.7)4.2--13.5 cm wide, directed toward base or somewhat outward; sinus hippocrepiform, parabolic to arcuate or arcuate with petiole decurrent, 1--6(8) cm deep; midrib broadly convex to shallowly sunken to flat, paler than surface above, convex, paler than surface, drying darker than surface below; basal veins 3--5 per side, with 0--1 free to base, 1--3(4) coalesced (0.7)1.3--4(7) cm; posterior rib naked for 0.5--2.6 cm, sometimes not naked, directed to the tip of the posterior lobe 1--3.5 cm distant from the lower margin of the posterior lobe; primary lateral veins (2)3--4 per side, departing midrib at a 40--60(70E) angle, more or less straight to the margins, streaked reddish below, broadly impressed to shallowly and obtusely sunken above, weakly convex and darker than surface below; minor veins moderately distinct, arising from both the midrib and primary lateral veins.

INFLORESCENCES erect, 1--3(4) per axil; peduncle 3.5--29 cm long, 8--12 mm diam., medium green, glossy, faintly white-striate near apex; spathe glossy, 7.5--18 cm long, 1.4--2.2 cm diam., weakly constricted midway above the tube, 1.9--2.2 mm diam. at constriction; spathe blade creamy-white to pale green or creamy-yellow, sometimes tinged faintly reddish outside, 6--7 cm long, 2.2--3.2 cm diam., (opening 6.7--9 cm long, 3.2 cm wide), whitish (at anthesis) to creamy-yellow inside, sometimes suffused with red; resin canals orange and appearing as continuous lines at least around the throat inside; spathe tube medium to dark green and light maroon band near base, sometimes weakly to heavily tinged reddish (B & K Red-Purple 5/7.5), white-striate outside, 5--7.5 cm long, 2--3.6 cm diam., reddish to dark maroon (B & K red-purple 2/10) inside; spadix sessile; more or less tapered toward apex, 6.7--11.1 cm long, broadest at or near the base, protruding strongly or weakly out of the spathe blade at anthesis; pistillate portion weakly tapered toward both ends, light green to yellowish green, (2.5)3.4--4.3 cm long in front, 2.9--3.8 cm long in back, 7--13 mm diam. at apex, 1--14 mm diam. at middle, 1--12 mm wide at base; staminate portion 5--8.4 cm long; fertile staminate portion white or light green, 10--11 mm diam. throughout, of nearly uniform diameter throughout or broadest in upper one-third, 9--13 mm diam. at base, 10--11 mm diam. at middle, 7--9 mm diam. ca. 1 cm from apex, broadest usually at the base, narrower than the pistillate portion, narrower than the sterile portion; sterile staminate portion as broad as the pistillate portion, (pre-anthesis) white to light gray, 9--14 mm diam.; pistils 1.1--2.3(3.5) mm long, 0.7--2 mm diam.; ovary (5)6--7-locular, 0.6--1.5(2) mm long, 0.8--1.3(1.6) mm diam., with sub-basal placentation; locules 0.7--1.1(2) mm long, 0.3--0.6 mm diam.; ovule sac 0.7--0.9 mm long; ovules 1--2 per locule, 2-seriate, contained within transparent, gelatinous ovule sac, 0.3--0.5 mm long, slightly longer than funicle; funicle 0.2--0.3 mm long, (can be pulled free to base), style 0.3--1.2 mm long, 0.8--1.6 mm diam., similar to style type B; style apex flat to shallowly rounded or concave; stigma brushlike to discoid or subdiscoid, purplish violet or golden honey-colored, 1--1.5 mm diam., 0.2--0.4 mm high, covering more or less entire style apex; the androecium truncate, prismatic, margins irregularly 4--6-sided, 1--1.7 mm long, 0.7--1.5(2.7) mm diam. at apex; thecae oblong, 0.4--0.5 mm wide, more or less parallel to one another; sterile staminate flowers blunt, irregular, dense, 4--6-sided, prismatic, 1.5--2(2.5--3.3) mm long, (1.2)1.5--1.6(2) mm wide. Berries pale to bright orange (white, immature); seeds yellow-orange, narrowly ellipsoid.

Philodendron wilburii ranges from northern Costa Rica to the Canal Area of Panama from near sea level to 2000 m elevation. This species is a highly versatile species ecologically, ranging from Premontane rain forest, Tropical Lower Montane wet forest, and Tropical Lower Montane rain forest in the highlands to Premontane wet forest and Tropical wet forest life zones in the lowlands.

Philodendron wilburii is a member of P. sect. Calostigma subsect. Glossophyllum ser. Ovata. This species comprises somewhat scandent plants with elongate internodes drying grayish to yellowish brown and closely fissured, mostly 1-ribbed, deciduous cataphylls, subterete petioles mostly longer than the blades, ovate to ovate-triangular blades often with the lobes directed somewhat outward, and 1--3 prominently pedunculate white to greenish inflorescences per axil.

Philodendron wilburii is probably most closely related to P. cotonense from the mountains of eastern Costa Rica. That species is distinguished by its yellowish brown-drying, more narrowly triangular blades averaging over two times longer than wide and thicker stems (2.5--3 cm diam. versus up to 2 cm diam. in P. wilburii). It also has typically longer peduncles (mostly more than 10 cm) and more ovules per locule (4--5, versus 1--2 in P. wilburii). The two species do not overlap in their distribution, but do occur in the same life zones.

Philodendron wilburii may be confused with P. straminicaule from Panama, but that species differs in having thicker and shorter internodes, 1-ribbed to sharply 2-ribbed cataphylls, and larger blades (rarely less than 35 cm long, versus rarely more than 35 cm for P. wilburii), with frequently more than 6 basal veins and 6 primary lateral veins (versus no more than 5 basal veins and mostly no more than 4 pairs of primary veins for P. wilburii). In addition, P. straminicaule frequently has the peduncle shorter than the spathe and has greenish white to lavender berries (versus having the peduncle rarely shorter than the spathe and orangish berries in P. wilburii). Philodendron wilburii is also similar to P. smithii which differs in having dried stem epidermis conspicuously yellow-brown.

This species is named in honor of Robert Wilbur (DUKE), who has made major contributions to the study of Costa Rican plants and who made one of the first collections of the species.

This species is here subdivided into two varieties.

Key to the varieties of P. wilburii:

A. Peduncles typically equal to or shorter than the spathe, usually less than 12 cm long; leaf blades with sinus hippocrepiform to parabolic, usually drying greenish to yellowish green below; Costa Rica (Alajuela, Cartago, Guanacaste, Heredia, Puntarenas, San Jose), 400--2000 m.
var. wilburii

A. Peduncles typically much longer than the spathe, usually more than 12 cm long; leaf blades with sinus usually arcuate or arcuate with leaf tissue decurrent on petiole, rarely hippocrepiform, usually drying reddish brown below; Costa Rica (Cartago and Puntarenas) and Panama (Veraguas), 900--1400 m, 40--450 m along the Pacific slope.
var. longipedunculatum Croat & Grayum Click on the Thumbnail to enlarge the picture.