Philodendron ligulatum var. ovatum Croat, var. nov.
TYPE: Panama. Veraguas: vicinity of Santa Fe, along road between Alto Piedra and Calovébora, 0.5 mi. N of Alto Piedra, on slopes of Cerro Tute, Parque Nacional Cerro Tute, 800--1030 m, 15 July 1994, Croat & Zhu 76888 (holotype, MO-- 4619517; isotypes, B, COL, CR, F, K, NY, PMA, US, VEN). Figure 272, 273.
Internodia 1--6(8) cm longa, 1--1.7(3) cm diam.; cataphylla 13--16 cm longa, incostata vel acute 2-costata; petiolus (10)15--19 cm longus, 7 mm diam.; lamina anguste ovata, subcordata basi, (14)18--26(39) cm longa, (8.5)12.5--16 cm lata, in sicco viridibrunnea supra, flavibrunnea infra; inflorescentia 1; pedunculus 12--16.5 cm longus, 7--10 mm diam.; spatha 11.5--18.5 cm longa, extus omnino viridalba; tubo spathae intus rubro basi.
Internodes 1--6(8) cm long, 1--1.7(3) cm diam., sometimes to 3 m or more long, sometimes covered with a thin layer of translucent white wax; cataphylls 13--16 cm long, unribbed to bluntly 1-ribbed or sharply 2-ribbed (ribs to ca. 4 mm high, incurled); petioles (10)15--19 cm long, 7 mm diam., subterete and obtusely flattened toward apex; blades narrowly ovate, weakly cordate at base, (14)18--26(39) cm long, (8.5)12.5--16 cm wide (1.57--1.65 times longer than wide), upper surface drying greenish brown to blackened, lower surface drying yellowish brown to dark olive-brown; posterior lobes rounded to narrowly rounded, 4--5 cm long, 5.5--6.6 cm wide, narrowly rounded to obtuse; sinus somewhat V-shaped, 2.5--3 cm deep; midrib convex to round-raised below; basal veins 2--3 per side, free to base; primary lateral veins 4--6 per side, departing midrib at a 55--65(75E) angle.
INFLORESCENCES 1 per axil; peduncle 12--16.5 cm long, 7--10 mm diam.; spathe 11.5--18 cm long, 1.5--2 cm diam. (0.8--0.95 times as long as peduncle), greenish white throughout; spathe tube sometimes pale to medium green outside, pale to medium green, sometimes red to purplish violet at base inside; spadix 10-12.5 cm long; pistillate portion 4--4.5 cm long; pistils 1.7--1.8 mm long, 1.7--1.8 mm diam., whitish; ovules 1 per locule, contained within transparent, gelatinous ovule sac, style similar to style type B; stigma subdiscoid, unlobed, often truncate.
Flowering in Philodendron ligulatum var. ovatum occurs in the rainy season. Collections at or near anthesis have been made in July, October, and November. Observations on a single plant in July showed a series of inflorescences with one at anthesis and one other on the same stem in post-anthesis condition. No fruiting collections are known.
Philodendron ligulatum var. ovatum is endemic to Panama, known only from Santa Fe in Veraguas and at El Copé in Coclé Province in Premontane rain forest at 770 to 1200 m elevation.
This taxon is characterized by its smooth, brown-drying stems, elongate internodes, sharply 2-ribbed to bluntly 1-ribbed deciduous cataphylls, subterete to D-shaped petioles about as long as the blades, ovate, subcordate blades with two to three pairs of free basal veins, and solitary inflorescences with the peduncle longer than the spathe.
Philodendron ligulatum var. ovatum differs from P. ligulatum var. ligulatum in having blades 1.5--1.7 times longer than wide (versus 2--4.5 times longer than wide in P. ligulatum var. ligulatum), peduncles longer than the spathe (versus shorter or about as long as the spathe for P. ligulatum var. ligulatum), and two ovules (rather than one) per locule. In addition, P. ligulatum var. ovatum usually occurs at higher elevations (770 to 1200 m) versus usually below 800 m for P. ligulatum var. ligulatum. Curiously, leaves of a few specimens of P. ligulatum var. ovatum dry yellowish green or brown, as opposed to the somewhat blackened color typically associated with the species.
Philodendron ligulatum var. ovatum may also be confused with P. lentii Croat & Grayum with which it also occurs in the El Copé region. That species differs in having usually more than ten pairs of primary lateral veins with several pairs of interprimary veins visible between them on the dried upper blade surfaces (versus only about five pairs of primary lateral veins and no interprimaries visible on the upper dried blade surface). In addition, the spathes of P. lentii are typically short-pedunculate.
Additional specimens examined.
PANAMA. Coclé: Alto Calvario, ca. 6 mi. N of El Copé, 770 m, 8E38'N, 80E35'W, Croat & Zhu 76754 (MO); Croat 67572 (MO); 68767A (CM, MO); 1200--1300 m, 8E38'N, 80E36'W, Sytsma 1903 (MO); 650--850 m, Folsom 6221 (MO, PMA); ca. 5 mi. N of El Copé, 900--1000 m, Croat & Zhu 75055 (K, MO, SCZ). Veraguas: vic. Escuela Agrícola Alto Piedra near Santa Fe, 1050--1150 m, Croat 48906A (MO).