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Araceae
Philodendron herbaceum Croat & Grayum
SUMMARY
Slender-stemmed vine clambering among understory shrubs and treeless or climbing (often twining) on small trunks to no more than ca. 3 m above ground, the fertile branches divergent with the inflorescences held erect. Internodes 0.5-11.4 cm long, 0.4-0.5 cm wide, green to dark green, weakly glossy to glossy, drying green, finely striate, the epidermis typically tessellate; roots present but few at distal nodes, to ca. 2.0 mm in diameter. LEAVES: Petiole (5.4-) 7.4-10.5 (-12.4) cm long, P/L=0.43-0.67 (-0.77), extensively sheathed, the sheath involute, the margins scarious and brittle, the free portion prolonged by 1.0-5.0 (-11.0) mm; unsheathed portion of petiole obsolete or to 0.3 cm long. Lamina (7.9-) 10.7-19.9 (-23.8+) cm long, (3.5-) 4.0- 8.8 (-10.3) wide, L/W=(1.78-) 1.99-3.39 (-3.97+), IQI=(1-) 4-9 (-11), membranous or thinly coriaceous, subchartaceous, senmiglossy to (less typically) glossy above, matte or (most typically) weakly glossy to glossy below, essentially concolorous or weakly bicolored, lanceolate to narrowly or ± broadly ovate, oblanceolate or elliptical (broadest below to above the middle), somewhat abruptly (rarely) to gradually short. to (much more frequently) long-acuminate apically [the acumen ca. 0.6-2.0 (-2.6) cm long], cuneate to rounded or subtruncate or (Centinela Ridge) subcordate basally; midrib sunken above, convex below; primary lateral veins (7-) 9-12 (-14) per side, 0.2-2.3cm apart, sunken above, convex below; minor veins obscurely to plainly visible below, darker and slightly prominulous; abaxial laminar surface drying densely and uniformly low-asperous-granular, with reticulate veins visible only marginally or rarely (Centinela Ridge) prominent throughout; stitching not evident, or cream-colored stitches obvious to abundant; resin canals may be visible flanking some primary veins; adaxial surface virtually smooth to (more usually) moderately to rather densely and uniformly low-granular or somewhat alveolate, with reticulate veins usually visible only toward the margins; white stitching very rare to (rarely) obscure and scattered; resin canals not evident. INFLORESCENCES solitary or (less commonly) paired; cataphylls occasional, 3.9-5.3 cm long, 0.35-0.55 cm wide, lanceolate, sharply 2-keeled; peduncle 1.6-4.0 (-4.5) cm long, P/S= (0.19-) 0.21-0.43, subterete, with raised whitish striations; spathe at anthesis 7.9-14.2 (-16.0) cm long, 1.4-2.5 cm wide, externally semiglossy, pale yellow-green to green below with the veins ± impressed and sometimes darker, yellowish green to greenish white, cream-colored or white distally, internally rather uniformly light green to white; spathe drying uniformly and densely granular with ± visible resin canals externally, often with white stitching, especially toward the margins, internally rather densely and finely farinose-granular and distantly reticulate-veined, rarely with white stitching toward the margins, with longitudinal secretory striations restricted to basal 1 cm or (more usually) not evident and apparently not present; acumen of spathe (0.3-) 0.5-1.4 cm long. Stipe of spadix (0.35-) 0.55-0.95 cm long; spadix (7.3-) 8.4-12.2 (-15.0) cm long, the fertile male portion (0.30-) 0.45-0.60 (-0.70) cm wide, white; apical sterile male zone 1.8-4.2 cm long; intermediate sterile male zone 0.25-0.80 cm long; female portion of spadix 2.0-3,9 (-4.1) cm long, F/S=(0.17-) 0.23-0.37, (0.45-) 0.60-1.20 (-1.55) cm wide, pale green or yellow- green; fertile male flowers 0.8-1.3 mm long, 0.6-1.3 mm wide, irregularly polygonal, columnar; apical sterile male flowers 0.95-1.25 mm long, 0.6-2.7 mm wide, ± mushroom-shaped; intermediate sterile male flowers 1.2-1.7 mm long, 1.1-1.8 mm wide, anvil- or goblet-shaped, with oily appearance; female flowers 1.3-1.9 mm long, 0.8-1.3 mm wide, the stylar canals probably mostly 4. INFRUCTESCENCES: Nearly ripe fruits very pale ochroleucous (essentially white) (Grayum 9988). Seeds (0.50-) 0.65-0.75 (-0.80) mm long, 0.2-0.3 mm wide, white, semicochleate to cochcleate, finely striate with the striae vaguely cancellate, drying light brown. Figs. 54-55.