Dieffenbachia isthmia Croat

Ortiz, Orlando Oriel, de Stapf, María Sánchez, Baldini, Riccardo Maria & Croat, Thomas Bernard, 2019, Synopsis of aroids (Alismatales, Araceae) from Cerro Pirre (Darién Province, Panama), Check List 15 (4), pp. 651-689 : 673

Dieffenbachia isthmia Croat ( Fig. 2D)

Material examined. Cerro Pirre, vicinity of station along Río Perisenico; 08°01′N, 077°44′W; 110 m; 26 Jul. 1994; T. B. Croat 77115 ( MO). Ibid., Rancho Plástico, camino hacia la cima del Cerro; 07°59′49″N, 077°42′45″W; 636 m; 15 Apr. 2016; O. O. Ortiz 2581 ( PMA).

Identification. This species is characterized by its relatively small size (usually up to 1 m), as well as by having milky sap, subcordate blades, blackish (when dry), rounded or auriculate petiole sheaths at apex and spadices with a sterile region. In the field, this species can be vegetatively confused with juvenile individuals of Dieffenbachia longispatha Engl. & K. Krause , which differs in having brownish-green blades (when dry) and decurrent petiole sheaths at apex.

Distribution and ecology. Colombia and Panama. Dieffenbachia isthmia represents a common species in the semideciduous and evergreen forests of Cerro Pirre. It usually grows below 800 m, and it is common to find them growing in colonies along rivers and streams.