Philodendron fortunense Croat, sp

Philodendron fortunense Croat, sp. nov.

TYPE: Panama. Chiriquí: Gualaca--Chiriquí Grande Road, vic. of Fortuna Dam, at junction of road to IRHE headquarters, 1200 m, 8E45'N, 82E18'W, 23 June 1987, Croat 66714 (holotype, MO-- 3635169; isotypes, AAU, B, CAS, CM, COL, CR, DUKE, EAP, F, GH, HUA, K, L, M, MEXU, NY, P, PMA, QCNE, RSA, S, SEL, TEX, US, VEN). Figures 179, 181--184.

Planta terrestris aut hemiepiphytica; internodia 3--6 cm longa, 4--7 cm diam.; cataphylla 18--32 cm longa, acute 2-costata, glauca, decidua; petiolus plus minusve D-formatus, 49--70 cm longus, 1.2--2.5 cm diam., glaucus, marginibus manifeste alatus, alis undulatus; lamina ovato-cordata vel oblongato-ovata, cordata basi, 36--60 cm longa, 22--44 cm lata; inflorescentia 4; pedunculus 7.7--8 cm longus, 8 mm diam.; spatha 20--21 cm longa, omnino virens, tubo spathae marronino, intus suffuso marronino in laminam; pistilla 7--8-locularia; loculi 9--10-ovulati.

Terrestrial or hemiepiphytic; stem appressed-climbing, 2--3 m long, thick, leaf scars conspicuous, 1.2--1.7 cm long, 2--2.5 cm wide; internodes smooth, to weakly pruinose, 3--6 cm long, 4--7 cm diam., about as long as broad, green to olive-green, epidermis drying smooth, semiglossy, light yellow-brown (B & K Yellow-Red 9/10), cracking with age, fissured transversely, sometimes with minute cracks perpendicular to axis; roots few per node, elongate, to 4 mm diam., light brown, smooth, weakly glossy, the epidermis cracking free upon drying; cataphylls thick, 18--32 cm long, sharply 2-ribbed (ribs 4 mm high), pale green, glaucous, dark short-lineate, deciduous.
LEAVES erect-spreading, clustered at or near stem apex; petioles 49--70 cm long, 1.2--2.5 cm diam., more or less D-shaped, becoming flattened and much broader than thick toward apex, medium green, rounded to flattened abaxially, with adaxial margins prominently winged (to 3 mm diam.), undulate to broadly flattened, surface dark short-lineate, glaucous; blades ovate-cordate to oblong-ovate cordate, moderately coriaceous to subcoriaceous, gradually acuminate to abruptly acuminate at apex, cordate at base, 36--60 cm long, 22--44 cm wide (1.3--1.8 times longer than wide), (0.85--0.88 times the petiole length), broadest slightly above point of point of petiole attachment, margins moderately undulate, upper surface medium green, semiglossy, drying greenish yellow, lower surface medium to pale green, glaucous, matte, paler, drying greenish yellow; anterior lobe 28--44 cm long, 10--20 cm wide, (0.9--1.3 times longer than wide), (1.8--2.9 times longer than posterior lobes), broadest at base; posterior lobes usually overlapping, 10--20 cm long, 10--20 cm wide, directed downward and slightly inward, obtuse to rounded; sinus oblong-triangular or closed, 10--19 cm deep; midrib flat to weakly raised, pale green, concolorous above, weakly raised, paler than surface below; basal veins 5--10 per side, 1--2 pairs free to base, the remainder mostly free, sometimes weakly coalesced 1--4 cm, drying weakly raised; posterior rib usually not present, naked and straight if present; primary lateral veins 7--11(15) per side, departing midrib at a 30--45E angle, straight or slightly arcuate to the margins, flat to sunken and drying darker than surface above, convex and darker than surface below; interprimary veins prominulous, weakly sunken to flat, concolorous above, flat and darker than surface below; lesser veins visible when dried; minor veins conspicuous, fine, darker than surface below, arising from both the midrib and primary lateral veins.

INFLORESCENCES 4 per axil; peduncle 7.7--8 cm long, 8 mm diam., medium green; spathe more or less erect, 20--21 cm long (2.5--2.7 times longer than peduncle), medium green throughout, glaucous, more or less acute at apex; spathe tube maroon, suffused maroon onto blade inside; spadix sessile; tapered, 20--21 cm long; pistillate portion tapered toward the apex, 5.2 cm long, 1.3 cm diam. at apex, 1.5 cm diam. at middle, 1.7 cm wide at base; staminate portion 14.7 cm long; fertile staminate portion tapered, 1.4 cm diam. at base, 1.3 cm diam. at middle, 1.1 cm diam. ca. 1 cm from apex, broadest at the base, narrower than the pistillate portion, narrower than the sterile portion; sterile staminate portion narrower than the pistillate portion, 1.4 cm diam.; pistils 4.5 mm long, 2.1--2.4 mm diam.; ovary 7--8-locular, locules 1.9 mm long, with sub-basal placentation; ovules 9--10 per locule, 0.4--0.5 mm long, slightly longer than funicle, style 2 mm long, 1.8 mm diam., similar to style type B; style apex flat; stigma subdiscoid, unlobed, 2 mm diam., 0.4 mm high, covering entire style apex; the androecium truncate, margins 4--6-sided; thecae oblong, 0.5 mm wide, contiguous; sterile staminate flowers blunt, 3.2 mm long, 1.7 mm wide.

Flowering in Philodendron fortunense is known only from April, and immature fruits from June. This corresponds to the late dry season and early rainy season in most of Panama, though this species occurs in an area with little seasonality.

Philodendron fortunense is endemic to Panama, known only from Chiriquí Province in the Fortuna Dam region (whence the name), from 1100 to 1300 m in elevation in regions of Premontane rain forest.

Philodendron fortunense is a member of P. sect. Philodendron subsect. Platypodium. This species is recognized by its thick stems with short, smooth (when fresh), green internodes, sharply two-ribbed, glaucous, deciduous cataphylls, ovate-cordate blades with usually overlapping posterior lobes, and pale, glaucous lower surfaces, and especially by the glaucous, broadly flattened petioles with undulate-winged margins.

Philodendron fortunense, one of the showiest, most distinctive species in the Central American region, is not easily confused with any other species. Its greatest similarity is to P. brenesii, with which it may occur, but that species differs in having proportionately longer, more or less terete petioles, and one to two inflorescences per axil (versus up to four inflorescences per axil in P. fortunense).

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Additional specimens examined.

PANAMA. Chiriquí: Fortuna Dam area, Gualaca--Chiriquí Grande, jct. of road to IRHE headquarters, 1200--1300 m, 8E45'N, 82E18'W, Croat 66529 (CM, ENCB, HNMN, JAUM, MO, MY, QCA, RB, W); 9.6 mi. beyond Los Planes de Hornito, 1300 m, Croat 48727 (AAU, COL, F, MO, OOM, QCNE); 48728A (MO); 10.1 mi. NW of Los Planes de Hornito, 1300 m, 82E17'W, 8E45'N, Croat 49814 (MO); 50000 (BR, CAS, CM, L, MO, QCA, SCZ, TEX); 4.5--5 km N of dam over Fortuna Lake, 1100--1135 m, 8E43'N, 82E17'W, Croat & Grayum 60000 (B, CM, K, MO, NY, RSA, US); 8 mi. beyond Los Planes de Hornito, 1.4 mi. W of Centro de Operaciones, trail to Río Hornito, 1010--1130 m, 8E44'N, 82E14'30"W, Croat 67921 (G, M, MO).