2. Aglaonema simplex (Blume) Blume, Rumphia. 1: 152. 1837.
越南万年青 yue nan wan nian qing
Caladium simplex Blume, Catalogus, 103. 1823; Aglaonema angustifolium N. E. Brown; A. birmanicum J. D. Hooker; A. fallax Schott ex Engler; A. longicuspidatum Schott; A. pierreanum Engler; A. schottianum Miquel f. angustifolium (N. E. Brown) Engler; A. siamense Engler; A. simplex f. angustifolium (N. E. Brown) R. N. Jervis; A. tenuipes Engler; Scindapsus tonkinensis K. Krause.
Plants perennial, erect. Stems dark green, cylindric, 40-80 cm tall, 1-2 cm in diam., rooting at nodes; internodes 2-3 cm, at distal part 5-10 mm; cataphylls early caducous, broadly linear, 4-7 cm, apex abruptly acute. Leaves usually 5 or 6, densely crowded at stem apex; petiole green, 6-15 cm, proximally sheathing; leaf blade initially involute, afterward spreading, pale green abaxially, dark green adaxially, ovate-oblong, 10-25 × 5.5-11 cm, thinly leathery, base truncate-rounded, subcordate, or decurrent, apex caudate-acuminate or abruptly long acuminate; primary lateral veins 6-8 per side, ascending and arching. Peduncle green, 2-6 cm. Spathe initially involute-tubular, afterward opening by a slit, cymbiform, ovoid, 3-4.5 × ca. 1.3 cm. Spadix 2.5-4.5 cm, slightly longer than or equaling spathe; female zone ca. 5 mm; ovary globose; ovule basal; stigma sessile, circular; male zone 2-3 cm; stamens 4; anthers 2-celled. Berry oblong, 12-18 × 7-10 mm. Seed oblong, 11-15 mm. Fl. Apr-Jun, fr. Sep-Oct.
Dense valley forests; below 1500 m. SW Yunnan [Cambodia, India (Nicobar Islands), Indonesia, Laos, Malaysia, Myanmar, Philippines (Palawan), Thailand, Vietnam].
Nicolson (Smithsonian Contr. Bot. 1: 38-41. 1969) maintained Aglaonema tenuipes and A. simplex as separate species primarily on inflorescence size and to a much lesser extent on phytogeography (A. simplex being a Sundaic element with A. tenuipes a N Thai/Indochinese species). However, there is complete introgression between even the extremes of the spathe size, while the presence of populations intermediate between "A. tenuipes" and A. simplex in the mountainous parts of C and SE Thailand seriously weakens the phytogeographical arguments.