Philodendron thalassicum Croat & Grayum, sp

Philodendron thalassicum Croat & Grayum, sp. nov.

TYPE: Panama. Chiriquí: Fortuna Dam area, trail to meteorological stationof Río Hornito, ca. 0.5 km S of Centro de Científicos, 1010--1030 m, 8E45'N, 82E18'W, 23 June 1994, Croat & Zhu 76297 (holotype, MO--4619518--22; isotypes, AAU, B, CAS, CM, COL, CR, DUKE, EAP, F, GB, GH, HUA, IBE, K, LE, M, MEXU, NY, P, PMA, QCA, RSA, S, SCZ, SEL, TEX, U, US, VEN). Figures 408--410, 415.

Planta terrestris or hemiepiphytica; internodia brevia longa, 2--4 cm diam.; cataphylla 14--46 cm longa, acute 2-costata, persistentia ut fibra; petiolus D-formatus, 38--109 cm longus, 2--14 mm diam., plerumque longior quam laminae; lamina triangulari-sagittata vel ovata, 42--77 cm longa, 16--52 cm lata, atriviridis supra, saepe veneta infra; inflorescentia 1--3; pedunculus 3--14 cm longus, 2--9 mm diam.; spatha 11--20 longa; lamina spathae extus alba vel creamea, intus viridalba; tubo spathae 3--7 cm longo, extus pallide viridi, intus virello vel ablo; pistilla (4)5--7(8)-locularia; loculi 16--22-ovulati.

Terrestrial or hemiepiphytic, growing to 4 m high in trees; stem appressed-climbing; internodes short, 2--4 cm diam., dark green, semiglossy, drying light yellowish brown, epidermis fragmented, reddish brown; roots several per node, <30 cm long, drying dark brown with epidermis ridged and splitting; cataphylls soft, 14--46 cm long, sharply 2-ribbed (ribs low), green or tinged pink when young to reddish brown or brown, drying brownish, persisting semi-intact, soon dilacerating; petioles 38--109 cm long, 2--14 mm diam., D-shaped, firm, flexible, sometimes with low, medial rib adaxially and with adaxial margins obtuse to rounded, medium green, weakly glossy, faintly to conspicuously dark- or striate-lineate, drying yellow-brown, dark brown to sometimes blackened; blades triangular-sagittate to ovate-triangular, subcoriaceous, conspicuously bicolorous, acuminate to long-acuminate at apex, sagittate at base, 42--77 cm long, 16--52 cm wide (0.8--1.8 times longer than wide), (0.6--1.4 times longer than petiole), usually shorter than petiole (averaging 0.9 times as long), upper surface dark green, matte or weakly glossy, sometimes glistening, drying dark brown, lower surface much paler (forming an areolate pattern on high magnification) and matte, often bluish green to whitish, drying bluish green if triangular-sagittate or yellowish brown if ovate-triangular, glaucous; anterior lobe 28--58 cm long, 18--51 cm wide (1.6--3.3 times longer than posterior lobes); posterior lobesbroadly obtuse to narrowly rounded, 13.5--25 cm long, 10--23 cm wide, rounded; sinus spathulate to parabolic, 9--12 cm deep; midrib broadly sunken to flat above, slightly paler, obtusely triangular and darker below; basal veins 5--11 per side, with 1--2(3) free to base, with a few veins coalesced for 5--9 cm; posterior rib prominently naked to 2.5--5 cm; primary lateral veins (4)12--18 per side, departing midrib at a 50--60E angle, weakly arcuate to more or less straight to the margins, C-shaped to sunken and slightly paler above, convex and concolorous below; minor veins conspicuous, darker than surface to obscure below, arising from both the midrib and primary lateral veins.

INFLORESCENCES more or less erect, 1--3 per axil; peduncle 3--14 cm long, 2--9 mm diam., coarsely white-striate; spathe 11--20 cm long, (1.15--2.8(4.7) times longer than peduncle); spathe blade white to cream and densely short-lineate outside, greenish white inside; spathe tube pale green and short-lineate outside, 3--7 cm long, greenish to white, sometimes faintly pinkish inside; spadix sessile to weakly stipitate; 12.8--16.6 cm long; pistillate portion 5.5 cm long in front, 3--3.5 cm long in back, 1.6--2 cm diam. midway, 1.5--1.6 cm diam. ca. 1 cm from apex; staminate portion 6.8--9.4 cm long; fertile staminate portion tapered toward apex, constricted (to 8--10 mm, 1.5--2 cm above base of sterile section) above sterile male flowers, 1 cm diam. at base, 1--1.6 cm diam. at middle, 5--7 mm diam. near apex; sterile staminate portion 1--1.7 cm diam. at base, 1 cm diam. at apex; pistils 2.8--3.8(6.2) mm long, 1.2 mm diam.; ovary (4)5--7(8)-locular, 1.7--2.3 mm diam., with axile placentation, wall sometimes embedded with angular crystal-like particles; locules 2.7(4.9) mm long, 0.5--0.6 mm diam.; ovules ca. 16--22 per locule, 2-seriate, 0.2--0.4 mm long, longer than funicle; funicle 0.1--0.2 mm long, adnate to lower part of partition; stigma lobed; style 1.3--2.1 mm diam., similar to style type B; style apex sloping to somewhat rounded, drying granular with an acute, turned up margin; stylar pores thickened, usually fused with the crown, sometimes free or nearly so, each with its own fringe of stigmatic papillae; style boss broad, shallow to quite shallow; the androecium truncate, prismatic, oblong, margins irregularly 4--6-sided, 0.9--1.2 mm long; thecae oblong, more or less parallel to one another; sterile staminate flowers prismatic to weakly clavate, irregularly 5--6-sided, 1.2--1.6 mm long. INFRUCTESCENCE with berries whitish (maturing).

Flowering in Philodendron thalassicum occurs throughout the dry season to the mid-rainy season (January through August), though no flowering collections are known from Feburary (although post-anthesis collections do exist). Post-anthesis collections are known from April and May, and especially, June, July, and August, and also from November (indicating that flowering may occur later than August). Immature fruiting collections are known from January, February, June, September, and November.

Philodendron thalassicum ranges from central Costa Rica to western Panama (Chiriquí) at (775)1000 to 2100 m elevation in Premontane rain forest, Tropical Lower Montane wet forest and Tropical Lower Montane rain forest life zones.

Philodendron thalassicum is a member of P. sect. Philodendron subsect. Philodendron ser. Impolita. This species is characterized by its short thick internodes, two-ribbed cataphylls persisting as fibers, more or less D-shaped petioles (averaging longer than the blades), internally greenish to white spathe tube, and especially by the pale matte, often bluish green lower leaf surfaces. The epithet "thalassicum" (from thalassicus, meaning sea green or bluish green) is derived from this coloration of the lower blade surface.

Philodendron thalassicum may be confused with P. hebetatum and P. strictum, which also have matte, much paler lower blade surfaces. Both differ in having subterete petioles drying conspicuously light yellow-brown, rather than sharply D-shaped and drying somewhat blackened as in P. thalassicum. In addition, both P. hebetatum and P. strictum have cataphylls drying yellowish and semi-intact and spathe tubes colored reddish, maroon, or violet-purple within.

Plants of P. thalassicum with sagittate blades might be confused with narrow leaved plants of P. jodavisianum or P. tenue but both of those species have blades that are semiglossy to glossy (not at all glaucous) below. More ovate blade-forms of P. thalassicum might be confused with P. schottianum, but the latter also usually has a semiglossy lower blade surface, cataphylls that persist semi-intact, and spathe tubes reddish internally.

Philodendron thalassicum is variable in blade shape, with some triangular-sagittate (e.g., Grayum et al. 3760, Croat 15876, 15745) and others ovate (e.g., Burger & Burger 7541, Burger & Stolze 5661, Burger & Liesner 6745). Those with ovate leaves sometimes dry brownish on the lower surface while those with the triangular-sagittate blades dry bluish green. No other differences between these two forms have been detected.

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Additional specimens examined.

COSTA RICA. Alajuela: Cantón Alfaro Ruiz, Tapesco de Zarcero, 1650 m, A. Smith NY1232 (F, NY); Alto Palomo, 1900 m, Lent 1844 (CR, F); Naranjo-Quesada, along Hwy 15, 3.2 mi. N of Zapote, 1560 m, Croat 46908 (MO); Cantón San Ramón, R. B. Monteverde, Cordillera de Tilarán, valle del Río Peñas Blancas, 1600 m, 10E19'15"N, 84E46'30"W, Bello 5151 (CR, INB, MO, NY); Monteverde reserve, 10E20'N, 85E50'W, Croat 61191 (cultivated) (MO). Cartago: Moravia, 3.5 km from Finca Racine, 1200--1300 m, Croat 36634 (CR, MO); Moravia de Chirripó--Turrialba, 1400--1600 m, I. Chacón 269 (MO); Río Dos Amigos--Río Villegas, W of Río Grande de Orosi, ca. 1650 m, 9E42'N, 83E47'W, Grayum et al. 3760 (MO, RSA); Quebrada Honda--Río Sombrero, ca. 1--2 km above El Muñeco, ca. 1400 m, Luteyn 3238 (DUKE); ca. 20 km E of Río Pacuare, on road toward Moravia, 1150 m, 9E50'N, 83E24'W, Thompson & Rawlins 1234 (CM); Quebrada Cangreja, 3 km S of Pan-American Highway, 1620--1650 m, 9E46'N, 83E57'W, Liesner & Judziewicz 14498 (CR, MO); Tapantí Hydroelectric Reserve, ca. 1 km S of junction of Quebrada Salto and Río Grande de Orosi, 1500--1800 m, 9E43'N, 83E47'W, Croat 36211 (MO); 1500--1700 m, 36078 (MO); 1525--1595 m, 79049 (CR, INB, MO); Croat & Grayum 68290 (MO, US); Grayum & French 5821 (INB, MO); 1600 m, Lent 964 (CR, F, US); 1500 m, 9E42'N, 83E47'W, Burger & Liesner 6745 (F, US); 1600 m, 9E42'N, 83E47'W, Burger & Stolze 5661 (CR, DS, F, WIS); 5,200 ft., Utley & Utley 7284 (MO); 1400--1700 m, 5184 (DUKE, MO); ca. 1600 m, 9E42'N, 83E46'W, Burger & Burger 7541 (F, MO); 1400--1600 m, 9E42'N, 83E47'W, Baker & Utley 201 (F, MO); Río Navarro, El Muñeco, 1400--1500 m, Standley & Torres 51371 (US). Heredia: 4 mi. N of Vara Blanca, 1350 m, Croat 35595 (MO); 35621 (MO); 9 km SE of San Ramón [de Sarapiquí], 1000 m, 10E16'N, 84E05'W, Loiselle 138 (MO); Paracito--Río Claro, vic. of Bajo La Hondura, 1100--1400 m, Croat 44500 (MO); Parque Nacional Braulio Carrillo, San Rafael de Vara Blanca, 1830 m, 10E11'50"N, 84E06'35"W, Herrera 246 (MO); Sarapiquí, 1750 m, 10E12'47"N, 84E06'05"W, Boyle & Boyle 2695 (MO); Finca Montreal, between headwaters of Río Volcán and Río San Fernando, 1800 m, 10E12'39"N, 84E06'45"W, Boyle 1084 (CR, MO); Volcán Barva, Río Peje--Río Sardinal, Atlantic slope, 1200--1400 m, 10E15'30"N, 84E05'W, Grayum & Herrera 7846 (MO); Río San Rafael, 1500 m, 10E13'N, 84E05'W, Grayum 7050 (MO). Limón: Cordillera de Talamanca, Kamuk massif, 1900--2300 m, 9E14-15'N, 82E59'W, Davidse & Herrera 29201 (MO). Puntarenas: Las Cruces Tropical Botanical Garden, 6 km W of San Vito de Java, 1200 m, 8E49'N, 82E58'W, Croat 57264 (CR, MO); Río Coto Brus, near Cotón, 23 km N of La Unión (on Panama border), Croat 26685 (CR, MO); Cerro Frantzius--Cerro Pittier, around Río Canasta, 9.5 airline km NW of Agua Caliente, 1500--1600 m, 9E02'N, 82E59'W, Davidse et al. 28365 (CR, MO, NY); Quebrada Kuisa, near crossing of Ujarrás--San José Cabécar trail, 2100 m, 9E20'30"N, 83E14'W, Grayum 10282 (CR, INB, MO); Monteverde Reserve, 1500 m, 10E17'N, 84E48'W, Hammel et al. 14206 (MO); 1500--1600 m, 10E18'N, 84E47'W, Haber & Zuchowski 10020 (CR, INB, MO, MV); 1500--1620 m, Pounds 334 (CM, MO); 357 (MO); 1450--1650 m, Burger & Baker 9772 (F, MO); Cerros Centinelas, 1550--1600 m, 10E18'N, 84E47'W, Grayum & Sleeper 3857 (CR, MO). San José: trail beyond Bajo La Hondura, towards Río Claro, 1100--1200 m, Luteyn 3318 (DUKE, MO); NE slope of Altos Tablazo, between Quebrada Tablazo and summit of ridge, 1700--1875 m, 9E50'N, 84E02'W, Grayum & Schatz 5181 (CR, MO); Parque Nacional Braulio Carrillo, Estación La Montura, Gómez et al. 20827 (CR, MO); General Valley, 1500 m, 9E27'N, 83E43'W, Burger & Barringer 11601 (F, MO); Cerro Hondura, between Río Patria and Río Zurquí, 1500--1600 m, 10E04'N, 84E01'W, Grayum & Sleeper 6131 (CM, MO). PANAMA. Chiriquí: NW side of Cerro Pando, Croat 15966 (MO); Fortuna Lake area, along Continental Divide, 1200 m, 8E44'N, 81E17'W, Croat 74975 (L, MO, NY, PMA, QCA); Río Hornito--Río Chiriquí, 1050--1100 m, ca. 8E44'N, 82E13'W, Stevens 18371 (MO); Boquete region, Monte Rey, Croat 15876 (MO), 15745 (MO); SW slope of Cerro Pate Macho, 1630--1780 m, 8E46'N, 82E25'W, Croat 66401 (CAS, F, K, MBM, MO, TEX, W); Quiel road, 10 km above Boquete, 5500 ft., Proctor 31831 (LL); Río Palo Alto--Cerro Pate Macho, ca. 6 km NE of Boquete, 1600--1700 m, 8E48'N, 82E23.5'W, Grayum et al. 6359 (MO, PMA, US); Cerro Horqueta, ca. 1650 m, Croat 27000A (MO).