International Aroid Society

16. Syngonium atrovirens Bunting, Acta Bot. Venez. 11:323. 1975. TYPE: Venezuela, Zulia, Hacienda Raizado (Hda. San Benito), ca. 1 km S of Concha, Bunting 2776 (MY-0254, holotype; VEN, isotype).

S. apurense Bunting, Acta Bot. Venez. 11: 322. 1975. TYPE: Venezuela, Apure, Reserva Forestal San Camilo, 7 km E of La Ceiba, 16 km E of El Jordan, 200 m, Steyermark, Bunting & Blanco 101942 (MY, VEN).

Scandent hemiepiphytes. Juvenile plants with petioles sharply sulcate, the margins narrowly winged; blades dark green, glossy above, pale beneath. Adult plants with stems 1.3-1.5 cm diam., gray glaucous when young, the epidermis brown and cracked in age; lower internodes 6-9 cm long, the upper internodes 2-4 cm long; petioles 25-35 cm long, gray glaucous, sheathed except for the upper 5-9 cm, the sheath inrolled, sometimes with elevated whitish striations, the unsheathed part sharply angular-winged adaxially, the lateral margins sharp, narrowly winged; blades trisect, thin to subcoriaceous, 20-25 cm long, dark green and often glaucescent above, paler green beneath, semiglossy; leaflets usually markedly free and petiolulate rarely confluent, the petiolules 5-15 cm long, rarely sessile; median leaflet elliptic to elliptic-ovate or oblong-elliptic, acuminate at the apex, obtuse to acute and attenuate at the base, 17-30 cm long, 5-11 cm wide, the primary lateral veins 4-5(-9) per side, weakly sunken, arising at an angle of (65-)70-80°(-90°), weakly curved to the collective vein, the tertiary veins distinct, the primary collective vein 2-6 mm from the margin, generally more or less straight, the margins sometimes finely undulate; lateral leaflets acute to narrowly rounded at the apex, slightly shorter than the median leaflet, the inner margin cuneate-acute, the outer margin prominently auriculate, the auricles acute to narrowly rounded at the apex, rarely broadly rounded with the auricles overlapping on the blade whose leaflets are not fully free, the primary lateral veins arising at a generally sharper angle than those of the median leaflets (ca. 50-60°).
Inflorescences solitary; peduncles gray glaucous, 5-7 cm long, 6-9 mm diam. at an-thesis, soon recurved; spathe 11-15.5 cm long; spathe tube narrowly oblong-ovoid, 5.5-7.2 cm long, 1.5-3.5 cm diam., not markedly constricted below the blade, semiglossy, light green on the outside, paler green within; spathe blade boat shaped when open, obtuse at the apex, cream colored on the outside, creamy white within, weakly tinged with pink toward the base; spadix sessile, 11 cm long, ca. 3 cm shorter than the spathe; pistillate portion of the spadix 1.6 cm long, 1.5 cm diam. (7 mm on drying); staminate portion of the spadix 8.5 cm long (dried), the sterile staminate portion 1.2-2.5 cm long, constricted weakly beneath the fertile part of the spadix.
Infructescences pendent, 8-9 cm long, 2.5 cm diam. (dried); syncarp ovoid-elliptic, only slightly shorter than the fruiting spathe. Figs. 33, 34.

DISTRIBUTION: Syngonium atrovirens is known for certain only from Venezuela and has been collected at elevations of 50-500 m in the states of Apure, Tachira, Merida, and Zulia. A sterile collection by Andre (419) from the Mag-dalena River Valley of Colombia (Naranjo-Carare) is probably also this species.
The species is closely related to S. yurimaguense from the upper Amazonian forests of Peru and Bolivia but differs from that species by its inflorescence which is much less constricted above the spathe tube. Both species have in common very similar leaves which have the primary lateral veins of the median leaflet arising from the midrib at almost a 90° angle.

VENEZUELA: APURE: East ofCeiba, Steyermark et al. 101942 (MY, VEN); SE ofCaserio San Camilo, Steyermark et al. 101478 (VEN). MERIDA: SE of El Vigia and El Quince, Bunting 2404A (MO, MY, VEN). TACHIRA: La Fria-La Grita at Las Pavas, Bunting 2494 (MY, VEN). ZULIA: S of Concha, Bunting 2776 (MY, VEN); Sierra de Perija, Steyermark & Fernanda 99633 (NY, US, VEN).