Philodendron cretosum Croat & Grayum, sp

Philodendron cretosum Croat & Grayum, sp. nov.

TYPE: Panama. Coclé: vicinity El Valle de Antón, at forested flat area near Finca Macarenita at La Mesa, 800 m, 8E36'N, 80E07'W, 6 July 1994, Croat & Zhu 76661 (holotype, MO--04619350--51; isotypes, AAU, B, CAS, CM, COL, CR, F, K, L, M, MEXU, NY, OOM, P, PMA, QCA, SEL, TEX, US, VEN). Figures 125--126, 144.

Planta epiphytica aut hemiepiphytica; internodia brevia, 1--3 cm diam.; succus calcareus, in sicco mox calcareus; cataphylla 23--42 cm longa, obtuse 1-costata, in sicco pallide flavibrunnea, persistentia ut fibrae pallidae; petiolus obtuse et late aut profunde et anguste sulcatus adaxialiter, 10.5--23.5 cm longus, 3--6 mm diam.; lamina linearis vel oblanceolata, 29--84.5 cm longa, 5--12 cm lata; inflorescentia 1--3; pedunculus (2.5)4--8.9 cm longus, ca. 10 mm diam.; spatha 9--13.5 cm longa; lamina spathae extus pallide viridi vel viridialba, intus viridialba; tubo spathae extus viridi, intus albo; pistilla 4-locularia; loculi cum 18--20-seminibus.

Epiphytic or hemiepiphytic; stem appressed-climbing, elongate, sap chalk-white; internodes short, 4--9 cm long on lower stems, short on flowering plants, 1--3 cm diam., as broad as long or slightly longer than broad, gray-green; roots drying dark brown, few per node; cataphylls thin, membranous, 23--42 cm long, bluntly 1-ribbed, green, drying pale yellowish brown, persisting as pale fibers; petioles 10.5--23.5 cm long, 3--6 mm diam., medium green, semiglossy, bluntly and broadly or deeply and narrowly sulcate adaxially, with adaxial margins obtuse or sometimes acute; blades linear to oblanceolate, chartaceous to weakly subcoriaceous, weakly bicolorous, drying greenish to yellowish brown on both surfaces, matte and paler below, acuminate to weakly acute at apex (the acumen apiculate), attenuate at base, 29--84.5 cm long, 5--12 cm wide (5.1--8.3 times longer than wide), (2.6--4.7 times longer than petiole), much longer petioles, broadest in upper one-third; midrib prominently and narrowly sunken above, thicker than broad, bluntly acute, glossy and darker than surface below; basal veins lacking; primary lateral veins 6--9 per side, departing midrib at a 25--45E angle, straight to weakly arcuate to the margins, sunken above, convex below; interprimary veins sunken above, slightly raised below; minor veins arising from midrib only; tertiary veins visible, darker than surface below. INFLORESCENCES 1--3 per axil; peduncle (2.5)4--8.9 cm long, ca. 10 mm diam., drying 3--5 mm diam., shorter than petiole, subterete or irregularly angled, white-striate; spathe subcoriaceous, semiglossy, 9--13.5 cm long, (1.8--3.3 times longer than peduncle), moderately constricted midway or just below the middle, abruptly acuminate at apex; spathe blade lanceolate, pale green to greenish white outside, 5.5--8 cm long, greenish white inside; spathe tube ellipsoid, green, short white lineate outside, 3.5--5.5 cm long, 1.8--2 cm diam., white (at anthesis) inside; spadix stipitate to 5 mm long; 11--15 cm long; pistillate portion white to pale greenish, weakly ellipsoid, 3--3.5 cm long; staminate portion 4.5--7.8 cm long; fertile staminate portion white; sterile staminate portion 1.2 cm diam.; pistils 0.6-0.9 mm long, 3 mm diam., drying blackish; ovary 4-locular, with axile placentation; ovules ca. 20 per locule, 2--3-seriate, 0.3--0.4 mm long; funicle ca. 0.4 mm long, adnate to lower part of partition, style similar to style type D; style apex flat, with a small style boss; stigma hemispherical; the androecium oblong, 3--5-sided, 0.8--1.2 mm long, 0.4--0.6 mm diam. at apex; sterile staminate flowers irregularly 4--6-sided, 1.5--2.1 mm long, 0.7-1 mm wide. INFRUCTESCENCE 6 cm long, 2.5 cm diam.; seeds 18--20 per locule, obovoid to weakly ellipsoid, 0.8--1 mm long, 0.4--0.5 mm diam.

Flowering in Philodendron cretosum occurs in both Costa Rica and Panama from March through July (except May), mid-dry season to early rainy season. It probably flowers over a broader period because post-anthesis collections have been made in January, April, June, July, and November. The post-anthesis collection in January means that the species may have flowered later than July or that there is some bimodality in the flowering. Immature fruits have been collected in November.

Philodendron cretosum ranges from Costa Rica to Panama, from near sea level to 900 m elevation in Tropical wet forest and Premontane rain forest life zones. The species is perhaps restricted to the Atlantic drainage but has been collected principally from areas along the Continental Divide in Panama.

Philodendron cretosum is a member of P. sect. Philodendron subsect. Canniphyllum. This species is recognized by its short internodes, white chalky sap (hence the name "cretosum," meaning "full of chalk"), persistent, thin, pale cataphyll fibers, bluntly sulcate petioles much shorter than the blades, and especially its linear to oblanceolate blades. Few other species in Central America have white chalky sap and no other species with white sap have narrow, non-cordate blades.

Philodendron cretosum is not easily confused with any other species in Central America. It resembles P. tenuipes Engl. from Ecuador, which also has elongated blades with acute bases and persistent cataphyll fibers, but that species differs in having blades drying darker brown with the primary lateral veins closer and more numerous (more than 15 pairs) and smaller spathes (usually less than 7.5 cm long).

One collection, Gómez et al. 19121, reportedly from the slopes of Volcán Miravalles along the Guanacaste-Alajuela border at about 1,500 m, would be well above the confirmed elevational range and in a Lower Montane rain forest life zone. It is doubtful if it was collected in this life zone or at that elevation. Neither Mike Grayum nor I have encountered this species above 600 m in Costa Rica.

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Additional specimens examined.

COSTA RICA. Alajuela: Reserva Biológica Monteverde Río Peñas Blancas, 500--800 m, Bello 1070 (CR, MO); 950 m, 1092 (INB, MO); Naranjo--Aguas Zarcas, along Highway 15, 8.5 km NE of Villa Quesada, 600 m, Croat 46978 (MO); Cañas--Upala, 4 km NNE of Bijagua, Río Zapote, 400 m, Croat 36295 (MO); San Ramón, Bittner & G. Herrera 2128 (CR). Guanacaste: Parque Nacional Guanacaste, Estación Pitilla, 550 m, 11E02'N, 85E25'20"W, Hammel et al. 17497 (CR, MO); slopes of Miravalles, above Bijagua, Gómez et al. 19121 (F, MO, US). Heredia: Cerros Sardinal, ca. 2--2.5 km N of Chilamate de Sarapiquí, 80--160 m, 10E28'N, 84E04'W, Grayum et al. 6148 (MO); La Selva Field Station, 50--100 m, 10E26'N, 84E01'W, Grayum 1894 (MO), 8546 (MO); Croat 61212 (MO). Limón: Barra de Colorado Refugio, Río Chirripocito-Río Sardina, 10--15 m, 10E38'N, 83E45'W, Grayum 9022 (CR, MO); Río Segundo, Asunción, Estribaciones Fila Matama, Cerro Matama, 300 m, Gómez et al. 23424 (MO). PANAMA. Coclé: 9.4 km above El Copé, 750--900 m, Croat 44743 (MO); El Valle region, La Mesa, above El Valle de Antón, 860--900 m, 8E38'N, 80E09'W, Croat 37344 (F, MO); 800--900 m, 67123 (F, MO, US); 13344 (MO); 775 m, Croat 74782 (M, MO); 900--1000 m, 8E40'N, 80E07'W, Knapp 5799 (MO, NY). Colón: Nuevo Tonosí--Río Indio, ca. 0 m, Croat 33555 (MO). Panamá: Cerro Campana, 400 m, Hutchison & Dressler 2974 (BH, F, M, US); Croat 17164 (F, MO, PMA); 150 m, 35985 (MO); 780--875 m, 25254 (MO); 800 m, 8E41'N, 79E56'W, 74775 (MO); Cerro Jefe region, 3--3.5 mi. NE of Altos de Pacora, 700--750 m, 9E15'N, 79E25'W, Croat 68697 (MO); along road to summit, 750--800 m, 9E14'N, 79E22'W, Croat 67090 (MO); El Llano--Cartí, 6.8 mi. from the highway, 350 m, Croat 49123 (MO); Campamento de los guardabosques de INRENARE, 800--900 m, 8E40'N, 79E55'W, Correa et al. 9516 (STRI). San Blas: Nusagandi, km 19.1, de Nevers & Herrera 7950 (MO). Veraguas: Santa Fe region, Escuela Agrícola Alto Piedra--Río Dos Bocas, 5--8 km from school, 730--770 m, Croat 25910A (MO).