Planta terrestris, raro hemiepiphytica; internodia 1--4 cm longa, 1.5--2.7 cm diam.; cataphylla 12--27 cm longa, acute 2-costata, persistentia semi-intacta nodis superioribus; petiolus U-formatus, obtuse sulcatus, 10--23 cm longus, 3--6 mm diam., crassior quam latus; lamina (22)30--49 cm longa, 9.8--21 cm lata, elliptica vel oblongo-elliptica, interdum oblanceolata, interdum attenuata apice, acute vel anguste rotundata, interdum attenuata basi; inflorescentia 1--2; pedunculus 2.5--6 cm longus; spatha 6.5--10 cm longa; lamina spathae extus saepe rubella plerumque atriviridi, intus pallide viridi vel marronina; tubo spathae extus pallido-lineato, intus pallide viridi vel marronino; pistilla (4)5--7(8)-locularia; loculi 14--18-ovulati; baccae albae.

Terrestrial or rarely hemiepiphytic; stem appressed-climbing, or creeping, leaf scars inconspicuous, obscured by cataphyll fibers; internodes short, semiglossy, 1--4 cm long, 1.5--2.7 cm diam., longer than broad, dark green to gray-green to reddish, obscured by cataphyll fibers; roots many, thin, wiry, descending, greenish brown; cataphylls 12--27 cm long, sharply 2-ribbed (unribbed to weakly to sharply 2-ribbed in Colombia), pale red to purple-violet, drying dark brown, sharply D-shaped, persisting semi-intact at upper nodes, as fibers below; petioles 10--27 cm long, 3--6 mm diam., U-shaped, thicker than broad, firm, dark green to reddish, tinged purple, somewhat flattened to obtusely or narrowly sulcate adaxially; geniculum pale green to reddish violet, 1 cm long 1.5 cm diam.; blades elliptic to oblong-elliptic, sometimes oblanceolate, rarely elliptic, coriaceous to subcoriaceous, conspicuously bicolorous, sometimes acuminate at apex (the acumen inrolled, 1--3 mm long), acute to narrowly rounded, sometimes attenuate at base, (22)30--49 cm long, 9.5--21 cm wide (1.8--3.5(4.5) times longer than broad), (1.6--3.2 times longer than petiole), about twice as long as wide, upper surface dark green, matte to semiglossy, lower surface moderately paler, semiglossy to glossy; midrib narrowly sunken, paler than surface above, narrowly convex, thicker than broad, matte, paler than surface and sometimes reddish green below; basal veins lacking or sometimes 1-2 per side, free to base; primary lateral veins 8--14(16) per side, departing midrib at a 40--55E angle, sunken to narrowly sunken, concolorous to paler than surface above, convex and darker than surface below; interprimary veins few, sunken to narrowly sunken, concolorous to paler than surface above, raised and darker than surface below; minor veins few, moderately obscure above, darker than surface below, arising from midrib only, sometimes prominulous and weakly undulate on drying.

INFLORESCENCES 1--2 per axil; peduncle 2.5--6 cm long, 2.5--5 mm diam., reddish, prominently green streaked; spathe 6.5--10 cm long (1.3--3.3(4.6) times longer than peduncle), red to maroon or violet-purple or sometimes green heavily tinged red, sometimes greenish white through; spathe blade frequently dark green (red in Colombia) outside, pale green to maroon inside; spathe tube short pale-lineate outside, 3--4 cm long, 2 cm diam., pale green to maroon inside; spadix more or less tapered, 6.8--8 cm long, broadest at the base; pistillate portion white to pale green, cylindrical, 2--3.7 mm long, 1--1.5 mm diam. at apex, 11--7.2 mm diam. at middle, 9--11(17) mm wide at base; staminate portion 3.9--4.9(6) cm long; fertile staminate portion cream, cylindrical to somewhat tapered, 10 mm diam. at base, 8 mm diam. at middle, 8 mm diam. ca. 1 cm from apex, broadest usually at base, narrower than the pistillate or sterile portion; sterile staminate portion as broad as the pistillate portion, 10 mm diam.; pistils 2.5 mm long, 1.6--1.9 mm diam., tinged reddish; ovary (4)5--7(8)-locular, 1.4 mm long, 1.6 mm diam., with axile placentation; locules 1.4 mm long, 0.5 mm diam.; ovules 14--18 per locule, contained within a gelatinous matrix, 2-seriate, 0.3--0.5 mm long, longer than funicle; funicle 0.2--0.4 mm long, adnate to lower part of partition, style 0.4--0.6 mm long, 1.6--1.8 mm diam., similar to style type B; style apex flat to weakly rounded; stigma usually subdiscoid, 1.1--1.3 mm diam., 0.2--0.5 mm high, covering entire style apex; the androecium truncate, prismatic, oblong, margins irregularly 4--6-sided, 0.7 mm long, 1.2--1.5 mm diam. at apex; thecae oblong to cylindrical, 0.5 mm wide, more or less parallel to one another and contiguous; sterile staminate flowers clavate, blunt, irregularly 4--6-sided, 2.3 mm long, 2 mm wide. INFRUCTESCENCE with pistillate spadix 4--4.5 cm long, 1.5--2.5 cm diam.; berries white (immature), 3.5 mm long, 2.6 mm diam. 12--14 per locule; seeds 7--9 per locule, whitish, oblong, 1.8 mm long, sharply tapered on one end.

Philodendron roseospathum ranges from Panama to Colombia. In Panama, this taxon is restricted to both sides of the Panama Canal, ranging from Veraguas to San Blas, mostly in Premontane rain forest or less frequently in Tropical wet forest life zones, at 350 to 1000 m elevation. In Colombia, it has been collected only in tropical pluvial forest at 100 to 900 meters.

Philodendron roseospathum is a member of P. sect. Philodendron subsect. Canniphyllum. The typical variety is recognized by its generally erect, frequently terrestrial habit, short internodes, and rosulate cluster of leaves with moderately short, bluntly sulcate, thicker than broad petioles. The dark green, elliptic-oblanceolate leaf blades are narrowly rounded to acute at the base. It is especially recognizable by its masses of weathered persistent cataphylls and clusters of inflorescences with reddish spathes (hence the name "roseospathum"). This species is unusual for the genus in that it is generally terrestrial. It has prospered in cultivation and is deemed an important horticultural introduction.

Philodendron roseospathum appears to be most closely related to P. cuneatum Engl. from the Pacific slope of Colombia, but the latter species differs in having acutely sulcate, C-shaped petioles and smaller, more narrowly pedunculate inflorescences with white spathe blades. It is also related to several other undescribed species from the Amazon basin.

Philodendron roseospathum is here divided into two varieties, with P. roseospathum var. angustilaminatum Croat differing from the typical variety in having somewhat longer petioles and proportionately much narrower blades (4.5 times longer than broad versus an average of 2.5 times longer than broad for the typical variety). See P. roseospathum var. angustilaminatum for additional differences.

Key to the varieties of P. roseospathum:
1. Blades oblong, ca. 4.5 times longer than wide; Panama (Colón), 915 m elevation
var. angustilaminatum

1. Blades more or less elliptic, ca. 2.5 times longer than wide; Panama to Colombia, 400--900 m elevation
var. roseospathum Click on the Thumbnail to enlarge the picture.