Philodendron immixtum Croat, sp. nov.
TYPE: Panama. Panamá: Comarca de San Blas, Río Playón Chico, 50--100 m, H. Herrera et al. 1167 (holotype, MO--4256423; isotypes, AAU, K, MEXU, PMA, US). Figures 233--236.
Planta hemiephytica; internodia (2)10--15 cm long, (7 mm) 1--1.5 cm diam.; petiolus subteres, actue D-formatus ad debiliter planatus; lamina anuste ovata vel ovato--elliptica, 16--36 cm 4longa, 5--12 cm lata; inflorescentia solitaria; pedunculus 5--13 cm longus; spatha 9--19 cm longa, lamina albo-viridis vel albus, tubo viridis extus, rubo vel purpureo intus; spadix 10--11 cm longus; ovario (3)4--6(8)-locularis; loculis 1(2) ovularia.
Hemiepiphytic; stem scandent, sap reddish, watery; internodes long, slender, more or less glaucous, (2)10--15 cm long, (0.7)1--1.5 cm diam., much longer than broad, dark olive-green matte to weakly glossy, becoming gray-green, drying light brown, epidermis sometimes cracking with loose flakes; roots ca. 5 per node, to 15 cm long, 2--3 mm diam., tannish gray, drying reddish brown, more or less smooth, long; cataphylls somewhat spongy, to 17 cm long, unribbed, weakly 2-ribbed or sharply (1--)2-ribbed (ribs 2 mm high), pale green, dark short-lineate, drying pale brown to yellowish brown, usually some deciduous, sometimes persisting somewhat intact, eventually fibrous, obtuse at apex, margins paler, yellowish; petioles 7.5--16(21) cm long, 2--10 mm diam., subterete, sharply D-shaped to slightly flattened adaxially, rounded abaxially, surface dark green-striate, matte to semiglossy, shortly dark lineate, with dark green ring around apex; blades narrowly ovate to ovate-elliptic, or rarely oblong-elliptic, subcoriaceous, semiglossy, strongly bicolorous, abruptly acuminate at apex (the acumen tightly inrolled to apiculate, 2--4 mm long), subcordate, rarely rounded at base, 16--36 cm long, 5--12 cm wide (1.9--3.7 times longer than wide), (1.3--3.1(3.8) times longer than petiole), about twice as long as petiole, broadest below middle, margins narrowly hyaline, upper surface drying green to grayish to brownish green; posterior lobes short, about as broad as long and held close to petiole; sinus shallow, 0--2.5(3) cm deep; midrib flat to weakly convex, concolorous or slightly paler than surface above, convex to bluntly acute, paler than surface below; basal veins lacking; primary lateral veins 4--8 per side, departing midrib at a 50--60E angle, more or less straight to weakly arcuate to the margins, sunken and paler than surface above, weakly raised and darker than surface below; interprimary veins weakly raised and darker than surface; minor veins distinct to weakly visible, darker than surface below, arising from both the midrib and primary lateral veins. INFLORESCENCES 1 per axil; peduncle 5--13 cm long, 3--7(11) mm diam., dark green; spathe 9--19 cm long, (1.1--2.1 times longer than peduncle), green, densely and obscurely short-lineate, narrowly acuminate at apex; spathe blade pale greenish white to white outside, pale greenish white, dark lineate inside; resin canals appearing as continuous lines, drying reddish brown, resin droplets forming on spathe surface within; spathe tube dark green in back, paler in front on open edges outside, red or violet-purple inside; spadix gradually tapered to apex, protruding out of the end of spathe, bluntly rounded to obtuse at apex, 10--11 cm long, broadest above the middle, constricted slightly above sterile staminate portion; pistillate portion pale green, cylindrical, 3.4--4.2 cm long, 3.7 cm long in front, 2.7 cm long in back, 9--11 mm diam. at apex, 10--11 mm diam. at middle, 9--11 mm wide at base; staminate portion 6.8--7.5 cm long; fertile staminate portion white, cylindrical to clavate, 9--12 mm diam. at base, 1.1--1.3 cm diam. at middle, 7--12 mm diam. ca. 1 cm from apex, broadest at the middle, broader than the pistillate portion, broader than the sterile portion; sterile staminate portion as broad as, narrower than or broader than the pistillate portion, more or less 12 mm diam.; pistils 1.9--2.3 mm long, 1.3--1.9 mm diam.; ovary (3)4--6(8)-locular, walls sometimes embedded with granular, crystal-like particles, locules 0.7--1.3 mm long, 0.4--0.7 mm diam., ovule sac 0.6--1.3 mm long, with sub-basal placentation; ovules 1(2) per locule, contained within transparent ovule sac, 0.4--0.7 mm long, longer than funicle; funicle 0.2--0.6 mm long, (can be pulled free to base), style 0.3 mm long, 0.9--1.4 mm diam., similar to style type B; stigma subdiscoid, unlobed, 0.7--0.9 mm diam., 0.2 mm high; the androecium truncate, margins 4--6-sided; thecae oblong to slightly ellipical, 0.4 mm wide, more or less parallel to one another; sterile staminate flowers 4--6-sided, 1--1.8 mm long, 1.1--1.7 mm wide. INFRUCTESCENCE with spadix yellowish orange, 8 cm long, 3 cm wide; berries concave at apex; seeds 1 per locule, 1.5--1.8 mm long, 0.6--0.7 mm diam., yellow-brown.
Flowering in Philodendron immixtum occurs during the last half of the dry season and the first part of the rainy season, March through May, with post-anthesis inflorescences seen from March through August, and fruits seen in July.
Philodendron immixtum ranges from Panama to Colombia (Golfo de Urabá), occurring at or near sea level (to ca. 140 m elevation), primarily along the Atlantic slope in Colón and Panamá Provinces but also in Panamá Province on the Pacific slope along the Río Majé. It occurs in Tropical wet forest, Premontane wet forest, and in wetter parts of Tropical moist forest life zones.
Philodendron immixtum is a member of P. sect. Calostigma subsect. Glossophyllum ser. Glossophyllum. The species is characterized by its scandent habit, long, slender, mostly light brown-drying internodes, slightly flattened petioles (about one-half or less as long as the blade), narrowly ovate to ovate-elliptic, green-drying blades which are usually cordulate at the base, as well as by the solitary inforescence with a spathe green, the base white on the blade at anthesis and red within on the tube.
The species has been confused with P. immixtum Schott (1856) (hence the name "immixtum," meaning "intermixed or mingled with") from Venezuela (Standley, 1944; Croat, 1978). The Schott paintings of P. immixtum show a single unattached leaf and unattached inflorescences and probably represent the same species as P. sphalerum Schott (1860). Schott paintings of P. sphalerum show some leaves which are virtually identical to the above mentioned drawings. Philodendron sphalerum differs from P. immixtum in having several small inflorescences per axil (rather than one, somewhat larger inflorescence for P. immixtum). Schott's original description of P. sphalerum did not mention an inflorescence so that his drawing of that must have come later than his description. Schott's original description of P. immixtum cited Venezuela as the type locality, not Panama, and the solid greenish inner spathe surface depicted in his paintings corresponds well to P. sphalerum but not to the material in Panama which has a reddish interior spathe surface.
Philodendron immixtum has also been confused with P. ligulatum. The latter species differs in having blades which are typically more nearly oblong-elliptic to narrowly obovate-elliptic, frequently broadest above the middle and drying usually much blackened. In addition, it has petioles which bear a conspicuous purple ring around the petiole at the apex. In contrast, the blades of P. immixtum typically dry grayish to brownish green and are broadest frequently below the middle. The species also differs in having petioles which lack the purple ring at the apex.
A number of sterile or immature collections from Nicaragua may represent this species, but if so, it is curious that the species has not been collected in Costa Rica (for that matter, not further west in Panama than Miguel de La Borda in Colón Province).
Additional specimens examined.
PANAMA. Canal Area: Balboa, Standley 28542 (US); Ft. Randolph, 28616 (US); road between Gatún Locks and Ft. Sherman, ca. 1 mi. E of Ft. Sherman, <25 m, 9E19'N, 79E57'30"W, Croat & Zhu 76282 (CR, GB, MO, PMA, TEX, US); Ft. Sherman, from Pina to 3 mi. NE, Liesner 1382 (MO, US); Barro Colorado Island, Croat 5064 (MO), 10865 (MO, SCZ); Shattuck 851 (F, MO); Wetmore & Woodworth 11 (F, GH); Aviles 89 (F); Fairchild 3079 (US); Parque Nacional Soberania, 140 m, 9E06'20"N, 79E37'20"W, Croat & Zhu 76987 (MO). Colón: 0.25 mi. N of María Chiquita on road to Portobelo, 11360 (F, MO); Río Indio--Miguel de la Borda, along ocean trail, 0 m, 36898 (MO); vic. of San Miguel de la Borda, 9896 (MICH, MO, NY, PMA, SCZ); 2 mi. W of Portobelo, 33574 (BR, DUKE, MO); Palma Bellas--Salud, near sea level, 36865 (MO); 4.5 km SW of Piña, 0--5 m, Nee 11713 (MO); 3 km S of Piña, 50 m, Sullivan 137 (MO); Portobelo, Croat & Porter 15613 (MO); Nuevo Tonosí--Río Indio, near sea level, Croat 33545 (MO). Darién: Cerro Pirre, 17 km N of El Real, along Río Perisenico, 100 m, 8E01'N, 77E44'W, Croat & Zhu 77093 (CM, MO); 77162 (CM, MEXU, MO, PMA, US). Panamá: Río Maje, W of Bayano Lake, ca. 2 mi. upstream, 30--60 m, Croat 34592 (MO).
COLOMBIA. Chocó. Mpio. Acandí, Golfo de Urabá, Bahía Zardí, 0-5 m, 8E23'N, 77E07'W, Betancur et al. 1238 (HUA, MO).