Dracontium soconuscum (Araceae)
Tuber hemispherical or rounded, 4-7cm diam., 5-9cm thick, flat above, rounded and white to brown below, 4-45cm below ground level; tubercles few, cylindrically elongated, 0.5-0.8cm diam., 0.5-1cm long, borne around the periphery of tuber; roots whitish or sometimes tinged green, to 3mm diam.; cataphylls 3 or 4, 3-47 cm long, 2-3.5 cm wide, pink or light brown (when dried), reaching or surpassing ground level. Leaves solitary or sometimes two or more per tuber; petioles 1-1.8m long above ground, 3-5cm diam. at midpoint, dark green or gray or whitish green, sometimes tinged brown or red-brown, weakly mottled, usually smooth in upper half and with irregular protuberances in lower half; juvenile blade sagittate, or sagittately lobed; mature blade ascending to 45o to the petiole spreading horizontally, 1-1.2m diam., subcoriaceous papyraceous, sometimes fenestrate, never variegated, without raphide cells or dark markings, semiglossy and dark green above, matte and medium green below; middle division 3 times or more trichotomously branched, 0.8-1.5 × 0.6-1cm, with terminal subdivision consisting of 3 sections, with each basal subdivision consisting of many segments; lateral divisions 3 times or more dichotomously branched, 0.8-1 × 0.5-0.8cm, with terminal subdivision consisting of 2 sections, with basal subdivision consisting of many segments; terminal and subterminal sections free, each consisting of many segments; leaf segments bilobed, broadly oblanceolate, more than 5cm wide on each side of the major ribs, oblanceolate or orbicular-ovate, at least some of the basal segments free from each other, often with contrastingly smaller rounded or triangular segments alternating with larger segments; apices acuminate, or acute; ultimate segments 7-17cm long, free from penultimate segments or rarely confluent with penultimate segments; other segments 5-15cm long; penultimate segments free from subterminal sections; :medial segments free from basal subdivisions; basal segments absent, free from each other; rachises patterned similar to petiole but in much paler shades, similar to petiole but in a much paler scale; tertiary veins obscure above and weakly raised below; bracteoles 1 to 3, 5-45cm long, 1.5-2.5cm wide, pink to light brown, the longest one longer than the peduncle, covering the basal half or more of the spathe. Inflorescence solitary or rarely two, appearing before new leaf; peduncle 4-45cm long above ground, 0.8-1.2cm diam. at midpoint, often almost completely subterranean (0-5cm above ground level), scarcely mottled, whitish tinged pink, smooth; spathe 6-8(10)cm long, 3-4(6)cm wide, non-cymbiform, constricted at a certain point and differentiated into a proximal tube and a distal lamina (blade), cucullate, arching 45o-90o, apex acuminate; 1-3cm long, 2.5-4(5)cm wide at widest point; lamina similar to the tube in length (or slightly longer); inner surface glossy, violet-purple or maroon, with translucent area obscure; outer surface olive-brown or maroon, semiglossy; margins entire, broadly overlapping in the lower half; veins obscure inside or raised outside, similar to the spathe in color, purple; spadix exposed, stipitate, cylindric, violet-purple, 1-4 × 0.5-1cm at anthesis, often with several appendages at apex, 0.5-0.8cm long when present; stipe 0.3-0.7 × 0.5-0.6 cm at an-thesis, light brown. Flower tepals (4)5 or 6(8), 2- 2.5mm long, 1mm wide, dark purple; stamens (5)6 or 7(9); filaments 1-1.5mm long; anthers 1-2mm long, slightly exserted; ovary 2- to 5-locular, pale green; stigma 3-lobed; style 0-1mm long above tepals, dark purple, not persistent. Infructescence with spadix 4-10cm long, 2-3.5cm diam. in fruit; berries 4-seeded, 0.8-1.4cm diam., 1-1.5cm thick, subglobose, 4- to 5-angular, apically truncate; young berries dark green; mature berries purplish brown, with abundant reddish dots; seeds 0.6- 0.9cm long, 0.5-0.6cm diam. (wide), reniform or triangular (±), dark brown, laterally depressed; dorsal ridges obvious, 3, continuous, monomorphic, more than 1 mm thick, 0.1-0.5 mm high, warty along both sides, appearing as strongly reduced lateral ridges.
Dracontium soconuscum is easily confused vegetatively with D. grayumianum, but that species differs in having seeds with five or six strongly interrupted dorsal ridges, whereas D. soconuscum has seeds with three obvious and continuous dorsal ridges.
The northernmost species of the genus, Dracontium soconuscum is known from the Pacific slope in southern Mexico (Chiapas) and northern Costa Rica (Guanacaste, Alajuela, Pluntarenas), and on the Caribbean slope in central Panama (Canal Zone).
It occurs in coastal lowland thicket or bushes of the Tropical moist forest (T-mf) life zone (Holdridge et al., 1971).