Usually hemiepiphytic, sometimes terrestrial or epilithic; stem usually appressed-climbing, leaf scars conspicuous, 7÷15 mm long, 7÷16 mm wide;

internodes glossy, (1)2.2÷3 cm long, 2÷3 cm diam., usually longer than broad or about as long as broad, tan or gray-green to dark green, epidermis drying yellow-brown with loose flakes, fissured conspicuously; cataphylls soft, spongy, 12-20 cm long, bluntly to sharply 2-ribbed, green, dark green short-lineate, rounded at apex, drying tannish to yellowish, deciduous, intact; petioles 21.5÷63 cm long, 4÷16 mm diam., subterete, spongy, medium green, obtusely flattened with obtuse angle toward apex adaxially, surface dark short-lineate, dark with a dark purple-black ring around apex; blades narrowly ovate, subcoriaceous, glossy, moderately bi-colorous, acuminate to long-acuminate at apex (the acumen inrolled, 1-4 mm long), cordate at base, 26.5-53 cm long, 11-31 cm wide (1.2-2.2 times

longer than wide), (0.7÷1.4 times longer than petiole), margins hyaline, convex is lower half of blade, upper surface dark green, drying dark gray-green to yellow-brown, lower surface light greenish, usually drying yellow-green to yellow-brown, sometimes olive-green; anterior lobe 18^11 cm long, 18÷30 cm wide, (1.8÷2.9 times longer than posterior lobes); posterior lobes (3.2)7.5-16 cm long, 8.7÷14.2 cm wide, obtuse to broadly rounded; midrib flat to broadly convex, paler than surface above, prominently raised, concolorous below; basal veins (3)4÷5(6) per side, with 0÷1 free to base, 1-2 coalesced (1.8)2.5-5.5(7.5) cm; posterior rib not at all naked or briefly so, usually 1÷ 1.5 cm (rarely to 2 cm); primary lateral veins 3÷6 per side, darker than surface below, departing midrib at a 50÷70¡ angle, ± straight, eventually weakly arcuate to the margins, sunken above, convex below; interprimary veins weakly raised, darker than surface below; minor veins numerous, sparsely visible, darker than surface below, arising from both the midrib and primary lateral veins. INFLORESCENCES erect, 2 per axil; peduncle 9÷22 cm long, (1)9÷12 mm diam., medium green, moderately spongy; spathe ± erect, 8.8-19.8 cm long, (0.5-1.4 times longer than peduncle), prominently constricted at anthesis; spathe blade yellowish green to green, glossy outside, 7 cm long, 1.7 cm diam., whitish green, minutely white-dotted, sometimes orange-striate inside; spathe tube ellipsoid, green outside, 8.5 cm long, 2.5 cm diam., light red to maroon (B & K red-purple 2/10) inside; spadix stipitate 6÷15 mm long; gradually to bluntly tapered to apex, 9.3÷16.9 cm long; pistillate portion pale green to greenish yellow, 3.3÷5.2 cm long in front, 2.2-2.5 cm long in back, 1.4 cm diam. at apex, 1.3÷1.6 cm diam. at middle, 1.6 cm wide at base; staminate portion 6.5÷11.3 cm long; fertile staminate portion creamy white, 9÷12 mm diam. at base, 1÷1.2 cm diam. At middle, 5÷7 mm diam. ca. 1 cm from apex, broadest at the middle, narrower than the pistillate and sterile portions; sterile staminate portion broader than the pistillate portion, creamy white, (9)1.1÷1.5 cm diam.; pistils 1.8÷2.3 mm long, 1.1 mm diam., creamy white; ovary 6-8-locular, 0.9÷1.2 mm long, 1 mm diam., Usually with basal, sometimes sub-basal placentation; locules 0.9÷1.1 mm long, 0.3÷0.4 mm diam.; ovule sac 0.9(1.2) mm long; ovules 1 per locule, contained within transparent ovule sac, 0.3÷0.4 mm long, about as long as funicle; funicle 0.3-0.4 mm long (can be pulled free to base), style 0.6÷0.8 mm long, 1.1 mm diam., similar to style type B; style apex ± sloping; stigma subdiscoid, greenish yellow, 1 mm diam., 0.3 mm high, covering entire style apex;

the androecium irregularly 5÷6-sided, sometimes oblong or quadrangular, 1.6-1.9 mm long, 0.9-1.2 mm diam. At apex; thecae oblong, 0.4-0.5 mm wide, ± parallel to one another and nearly contiguous; sterile staminate flowers blunt, irregularly 4-6-sided, sometimes prismatic, (1)1.6÷2 mm long, (1.2)1.7÷1.8 mm wide. Berries while or sometimes yellowish; seeds 1 per locule, tan, oblong, 2 mm long, 0.8 mm diam.

Flowering in Philodendron smithii occurs principally in the dry season, and flowers have been collected from December to April (but also July). Postanthesis collections are common from February through July but with a few in October, November, and December. The latter, especially those in October and November, are the most aberrant, since even if this species is cued to flower by the onset of the dry season (which appears to be the case), they would appear to have flowered too early. This may be explained by the fact that the dry season starts much earlier in Mexico and Guatemala than in Costa Rica and Panama.

Philodendron smithii ranges from Mexico (mostly in Chiapas, Tabasco, and Quintana Roo) to Guatemala, Honduras, and Nicaragua on the Atlantic slope at 40 to 1630 (mostly less than 600) m elevation. It is known from "Selva Alta Perennifolia" and "Selva Mediana Subpcrennifolia" in Mexico as well as from Tropical moist forest and Subtropical wet forest in Guatemala.

Philodendron smithii is a member of P. sect. Colostigma subsect. Glossophyllum ser. Ovata. This species is characterized by its conspicuously fissured tan internodes, which are about as long as to longer than broad; sharply two-ribbed, deciduous cataphylls; spongy subterete petioles; usually blackish, narrowly ovate-cordate leaf blades; long-pedunculate inflorescences; and externally green spathes that are maroon inside the tube.

Philodendron smithii is not easily confused with any other species in Central America. It is most similar to P. panamense, which is endemic to Panama, and shares with that species similarly dark-drying ovate-triangular, long-petiolate blades and long-pedunculate inflorescences. Philodendron panamense differs in having much shorter internodes (shorter than broad on flowering plants), weakly one-ribbed cataphylls, moderately firm petioles, and spathes green on the tube outside with a white blade and greenish white throughout within (vs. green throughout outside and maroon on the tube within for P. smithii).

Philodendron smithii is also similar to P. straminicaule and P. wilburii, both from Costa Rica and

Panama and both differing in having steins drying gray-green to grayish or stramineous rather than conspicuously yellow-brown as in P. smithii.

Mayo (1986) reported that P. smithii lacks superficial resin canals in the spathe and that instead resin production has entirely shifted to the spadix. However, we observed resin canals on the inner surface of both the spathe and the blade in this species.

A noteworthy collection is Standley 52776 from the Lancetilla Valley in Honduras. It has leaf blades with broadly flaring lobes, but otherwise does not differ from other collections.

One outlying collection in Mexico, from the state of Ouerctaro at 450 m (Lopez 539), is believed also to be this species.

Mayo (1989) reported style type E for Croat 47913, hut my investigations of flowers of that collection showed no evidence of an annulus on the ovary, and while there was a slight depression in the style apex, the latter was not deemed sufficiently funnel-shaped to qualify for anything except a type B style.

The type specimens (/. D. Smith 1535), though unequivocal, were distributed by Engler with a printed label bearing the name Philodendron donell-smithii, but no such name appears in Engler's publications.