4. Syngonium chiapense Matuda, Revista Soc. Mex. Hist. Nat. 11:94-95. 1950.

TYPE: Mexico, Chiapas, Piedra de Huixtla, Matuda 18619 (MEXU, holotype; DS, isotype).

S. llamasii Matuda, Cact. & Sucul. Mexico 2:79, fig. 52. 1957. TYPE: Mexico, Chiapas, El Suspiro, near Ocozocuautla, 600 m, Matuda 32637 (MEXU, holotype).

Juvenile plants with glaucous stems; internodes 5-23 cm long, less than 1 cm wide; petioles sheathed 1/2-3/4 their length, blades ovate-cordate, 9-30 cm long, 5-17 cm wide, acuminate at the apex. Adult plants with stems green, usually glaucous; internodes 12-20 cm long, becoming closer at the apex, 2-6 cm long, 2.5-4 cm diam.; petioles 30-60 cm long, sheathed about 4 A their length, subterete above the sheath, weakly flattened on the upper surface; blades with the upper surface matte, seldom weakly glossy, the lower surface matte, much paler, ovatecordate to 3-lobed, abruptly acuminate to obtuse-mucronate at the apex, the entire blade with the anterior lobe 28-65 cm long, 18-35 cm wide, broadest at about the middle, only slightly or not at all constricted at the base, the posterior lobes rounded or subhastate, the sinus very narrow or open and broader than deep, the posterior rib sometimes naked 5-20 mm; 3-lobed blades with the anterior lobe broadly ovate, 28-52 cm long, abruptly constricted at the base and confluent with the posterior lobes, the latter ovate to obovate, 10-20 cm long, directed backwards or at ca. 90' angle to the anterior lobe, acute to narrowly rounded at the apex, bluntly auriculate at the base on the lower side; primary lateral veins mostly 5-8(-10) pairs, slightly sunken; the primary lateral veins convexly raised, the tertiary veins clearly visible.
Inflorescences 1-3; peduncles to ca. 10 cm long and erect at anthesis, green and glaucous, 12-18 cm long and pendent in fruit; spathe tube ellipsoid to oblong-ovoid or cylindroid, greenish outside, glaucous, 5-7 cm long, to 3 cm diam. inside, yellowish white at the base, purplish at the apex; spathe blade broadly elliptic, white, shortly cuspidate at the apex, 5-9 cm long, 5-7 cm wide; pistillate portion of the spadix 3-4 cm long, the ovary ca. 5 mm long, 3 mm wide; staminate portion of the spadix ca. 5-9 cm long, to 1.5 cm diam., the staminate flowers ca. 3 mm long, the anthers 4, cross Figs. 5, 22.

DISTRIBUTION: Syngonium chiapense is known for certain only from southern Mexico (Oaxaca and southern Veracruz), but a sterile collection from Guatemala (Baja Verapaz) also appears to be this species. The species occurs only on the Atlantic coast from sea level to more than 1200 m but most commonly occurs above 350 m in life zones ranging from tropical moist forest through tropical wet forest.
Syngonium chiapense is perhaps most closely related to S. macrophyllum. The two species have nearly identical juvenile leaves and both have glaucous stems and inflorescences in Mexico. The adult foliage of S. macrophyllum with 7-9 free leaflets is never confused with this species which is commonly entire or with merely a single pair of confluent posterior lobes.
Fruits have been seen July-September.

GUATEMALA: BAJA VERAPAZ: S of Purulha, Croat 41218 (MO).MEXICO: CHIAPAS: Comaltitldn, Matuda 17882 (MEXU); N of Ocozocoautla, Croat 40662 (MO); Piedra de Huixtla, Matuda 18619 (DS, MEXU). OAXACA: Vicinity of Valle Nacional, Croat 39720, 39754, 39805, 43913 (MO), 48016 (CAS, MO, MEXU), Moore & Bunting 8895 (BH, MO). VERACRUZ: E of Coatzacoalcos, Croat 40060 (MO); S of Catemaco, Moore & Bunting 8926 (MO), 8938 (BH, MO).