Philodendron sulcicaule Croat & Grayum, sp. nov.
TYPE: Costa Rica. Limon: 7 km SW of Bribn, 100-250 m, ca. 9¡36'N, 82¡54'W, 4 May 1983, Gomez, Liesner & Judziewicz 20473 (holotype, MO-3160203; isotypes, B, CR, K, PMA, US). Figures 399, 400, 403.
PIanta hemiepiphytica; internodia 6-16 cm longa, 5÷ 13 mm diam., profunde sulcata; cataphylla 12 cm longa, incostata, vel acute 1-coslata, rare acute 2-costala, decidua intacta; petiolus 11-20 cm longus, subteres, leniter complanatus adaxialiter; lamina ovato-cordata, abrupte vel longa acuminata, 14.5-24 cm longa, 9.6-15 cm lata; nervis basalibus 3 utroque, infirmis; nervis lateralibus I obscuris; inflorescentia 1-4(5); pedunculus tennis, 3.5÷10 cm longus, 1-3 mm diam.; spatha (4.5)5.8-11 cm longa, omnino alba, tube spathae intus rubro, roseo aut purpureo basi; pistilla 1÷5-locularia; loculi 1-ovulati.
Hemiepiphytic vine; stem scandent, drying yellow, glossy; internodes deeply sulcate, prominently ribbed, semiglossy, 6÷16 cm long, 5÷13 mm diam., longer than broad, olive-green; epidermis becoming brown, breaking free on bending stem; roots red-brown, slender, curled, 8-20 cm long; cataphylls 12 cm long, unribbed to sharply 1-ribbed, rarely sharply 2-ribbed, green rarely pink, deciduous intact; petioles 11÷20 cm long, 4÷8 mm diam., subterete, dark green, weakly flattened adaxially, semiglossy; blades ovate-cordate, subcoriaceous, semiglossy, moderately bicolorous, abruptly- to long-acuminate at apex (the acumen apiculate, to 4 mm long), cordate at base, 14.5÷24 cm long, 9.6÷ 15 cm wide (1.3--1.9 times longer than wide), (0.9-1.6 times longer than petiole), about two-thirds as long as petiole, margins drying moderately undulate, upper surface dark green, drying usually dark brown, semiglossy to matte, lower surface paler, drying light brown to greenish brown, sometimes yellowish brown, semiglossy; anterior lobe 10÷19.6 cm long, 7÷15 cm wide (2.6÷3.8 times longer than posterior lobes); posterior lobes 3.5-6 cm long, 2.7÷6.4 cm wide, rounded-obtuse to nearly acute; sinus arcuate with blade decurrent on petiole to short-hippocrepiform; midrib flat to weakly raised, concolorous above, convex, concolorous to paler than surface below; basal veins to 3 per side, weak, 1 sometimes free to base, the remainder coalesced 0.5÷2 cm; posterior rib naked for all its length; primary lateral veins obscure above, obscure below; minor veins distinct, fine, close, arising from the midrib only; "cross-veins" sometimes visible.
INFLORESCENCES 1-1. (5) per axil; peduncle 3.5-10 cm long, 1÷3 mm diam., reddish, whitish or purplish, slender; spathe (4.5)5.8-11 cm long, (0.9-1.1(2) times longer than peduncle), weakly constricted midway, 5 mm diam. at constriction, white throughout, becoming greenish (post-anthesis), rarely reddish (Gomez el al. 20473), cuspidate-acuminate at apex (the acumen ca. 1.5 mm long), white inside; resin canals appearing as intermittent lines in lower two-thirds of spathe, extending into upper part of spathe tube, drying blackened; spathe tube 3^4. cm long, red, pink, or purple at base inside; spadix sessile; slender, acute at apex, 4.5÷7.7 cm long, broadest at the middle of the staminate portion, constricted scarcely or not al all above the sterile staminate portion; pistillate portion while, 2.5 cm long, 4.5 mm diam. midway, 3.5-4.5 mm diam. at apex and at base; staminate portion 3÷5.2 cm long; sterile staminate portion cream, 3-4 mm diam.; pistils white; ovary 4÷5-locular, with ± sub-basal placentation; locules 0.4 mm long, 0.2÷0.3 mm diam.; ovule sac 0.4 mm long; ovules 1 per locule, contained within translucent or transparent ovule sac, 0.2÷0.3 mm long; funicle 0.1÷0.2 mm long (can be pulled tree to base), style similar to style type B; style apex flat; stigma subdiscoid, unlobed, ± truncate, 0.4÷0.5 mm diam., 0.1 mm high, covering center of style apex; the androecium margins irregularly 4÷6-sided, 0.6-1.2 mm long. IN-FRUCTESCENCE peduncle, 8 cm long, 1 cm diam.
Flowering in Philodendron sulcicaule occurs during the dry season and early wet season (December through May, though no flowering collections have been seen from April). Post-anthesis collections have been seen from March and April. No fruits have been seen. Philodendron sulcicaule ranges from extreme southeastern Costa Rica to the Atlantic slope of Panama, from 100 to about 700 m elevation (though generally less than 300 m) in Premontane wet forest transition to Tropical wet forest life zones. Philodendron sulcicaule is a member of P. sect. Calostigma subsect. Glossophyllum ser. Ovata. The species is characterized by its scandent habit; deeply sulcate stems drying yellow and glossy; unribbed, deciduous cataphylls; subterete petioles weakly flattened adaxially; and ovate-cordate blades with obscure primary lateral veins and up to four pairs of weak basal veins. Also characteristic are the numerous (up to five per axil), small, slenderly pedunculate inflorescences with spathes white outside (sometimes tinged red) and red to purplish in the base of the lube.
Philodendron sulcicaule appears closest to an undescribed species from Bajo Calima, Valle Department, Colombia (e.g., Croat 70137). Though the latter species has the same habit, petiole shape, leaf size and shape, and ribbed yellowish stems, it differs in having while cataphylls, usually 3-4 primary lateral leaf veins, and 3÷5 basal veins with a well-developed posterior rib. In addition, the spathe tube is reddish outside and the entire inner surface is creamy-while (vs. usually white outside and reddish to purplish inside the tube in P. sulcicaule).
In Central America, Philodendron sulcicaule resembles P. purpureoviride and P. microstictum, both of which are vines with similar leaves. Philodendron purpureoviride differs in having solitary, stout inflorescences (instead with up to three or four smaller inflorescences) and leaf blades with distinct primary lateral veins. Philodendron microstictum differs in having blades broader than long (vs. longer than broad in P. sulcicaule).