18. Syngonium erythrophyllum Birdsey ex Bunting, Baileya 14:17. 1966. TYPE: Panama, Canal Zone, near Fort Randolph near the Atlantic coast, Maxon & Harvey 6536 (US, holotype).

Juvenile plants often solitary; stems with short internodes, later scandent, branching, slender, leafy; blades ovate, 3-9 cm long, ± cordate at the base, the lobes rounded, the sinus ± arcuate with the decurrent petiole, the upper surface blackish green, the lower surface at first green, soon becoming deep violet purple;
juvenile blades on climbing stems larger, simple, sagittate, dark green above, deep violet purple below, 9-17 cm long, becoming indistinctly 3-lobed; petioles 11-20 cm long, sheathed to near the apex. Adult plants with stems sometimes branching, green, not glaucous, usually less than 1 cm wide, the periderm thin, minutely papillate, flaking and pale reddish brown at maturity; petioles 9-20 cm long, sheathed ^s or nearly throughout its length; blades trisect, subcoriaceous, the surface dark green and shiny above, paler beneath, usually green, sometimes violet purple; leaflets usually completely free, spreading or slightly overlapping, acuminate to rounded at the apex, ending abruptly with a minute apiculum; median leaflet elliptic to lanceolate-elliptic or narrowly ovate, 10-22 cm long, 4.5-10 cm wide, obtuse to attenuate at the base; lateral leaflets 4.5-10 cm long, 1.2-4.3 cm wide, elliptic to lanceolate or oblong, obtusely and narrowly rounded at the apex, the base inequilateral but not auricled. Inflorescences usually 2 or 3 per axil; peduncles 3-11 cm long, green, not glaucous, erect at anthesis, pendent in fruit; spathe equalling or longer than the spadix; spathe tube green, 1-A cm long, 1-1.5 cm diam., ovoid to ellipsoid; spathe blade white, ovoid to ellipsoid (when flattened), 8-11 cm long, 5-6 cm wide, weakly reflexed away from the spadix at anthesis; spadix 9-13.5 cm long; pistillate portion of the spadix to 1.5-1.8 cm long, the pistils ca. 1.4 mm diam., the stigmas discoid, ca. 0.9 mm diam.;
staminate portion of the inflorescence 6.5-10 cm long, (the fertile part 6-9 cm long), the flowers 4-androus, truncate or slightly refuse at the apex, the pollen white in arachnoid clusters. Infructescences ovoid, yellowish green, 3-5 cm long, the tube opening at maturity; seeds white, ± oblong, rounded on one end, apic-ulate and angled on the other end, 6-7 mm long. Figs. 41, 46.

DISTRIBUTION: Syngonium erythrophyllum is known only from Panama at elevations from sea level to 350 m in tropical moist forest and premontane wet forest life zones. Birdsey (1955) reports that this species may also occur in the Reventazon Valley of Costa Rica (provinces of Cartago and Limon) because he saw similar juvenile leaves on Syngonium plants collected there.
It is not confused with any other species and is recognized by its thick, trisect, slightly auriculate leaves with violet purple lower surfaces, at least on juvenile blades. Stems dry with a conspicuous, flaky, reddish brown periderm. The frequently rounded and apiculate-tipped leaflet apices are another useful character in recognizing the species.
On Barro Colorado Island this species produces abundant juvenile plants but few adult plants were seen during more than three years of field work there.
Flowers have been found mostly March-June and fruits in August-September.

PANAMA: CANAL ZONE: Barro Colorado Island, Birdsey 349 (UC, US), Croat 6208, 8637, 9124, 11709 (MO), 11778 (F, MO, US), 14955 (F, MO), Knight s.n. (US); Near Fort Randolph, Maxim & Harvey 6536 (US), Shattuck 31 (F), Wetmore & Woodworlh 31, 875 (F, GH). PANAMA: El Llano-Carti Road, Croat 33800, 34801 (MO), Folson 2258 (MO).