Aglaonema nitidum (Jack) Kunth

Aglaonema nitidum

Aglaonema nitidum (Jack) Kunth, 1841, p. 56.

Calla nitida Jack, 1820, p. 24.

Stem erect or with lower part reclining on ground in larger plants, to 1 m or taller, 0.5–5 cm thick. Internodes 0.5–2.0 cm long. Petioles (8) 11–26 (29) cm long, 0.4–0.9 times as long as the leaf-blade, often in two spirals. Sheaths with scarious margins, (5) 9–22 (28) cm long, (0.4) 0.7–1.0 times as long as the petioles. Leaf-blades narrowly elliptic to narrowly oblong or oblanceolate, (11) 20–45 (50) cm long, (4) 7–16 (20) cm wide, length/width ratio 1: (2.1) 2.7–3.6(4.3); base acute to attenuate, rarely broadly acute; apex often apiculate, acuminate to broadly acute or shortly acuminate; variegation usually not present; when present, either in bars following the venation or in rather irregularly scattered blotches; venation usually undifferentiated in dry material but sometimes weakly differentiated into 5–9 or more primary veins diverging from the midrib at 35°–55°; texture coriaceous. Peduncles rarely solitary, 2–5 together, (5) 10–17 (21) cm long, commonly equaling or surpassing the subtending petiole. Spathe light green but frequently turning white with age, eventually withering, 3–7 (8.5) cm long, decurrent for (0.4) 1–1.6 (2.0) cm. Stipe 0.2–0.9 cm long. Spadix cylindric, equaling or slightly exceeding spathe, (1.3) 4–7 cm long; pistillate portion (0.2) 0.5–1.0 cm long (to 2 cm in fruit), pistils 16–37, scattered at anthesis, stigmas yellowish, to 0.3 cm broad, the style weakly constricted; staminate portion (1.1) 2.5–5.0) (6.0) cm long to 1.5 cm thick, commonly rotting or shriveling soon after anthesis. Fruits white.

DISTRIBUTION.—Southern Burma, Malaysia, Sumatra, and Borneo (Figure 2).

HABITAT.—Lowland primary dipterocarp forest in damp and well-shaded place. Found in freshwater peat-swamp forests and on limestone but in pockets and damp ravines.

FLOWERING TIME.—Nonseasonal. The species is largely restricted to the equatorial region, where rainfall is daily (convectional) rather than seasonal and the plants live in dark places where the humidity is always high.

There are two important taxonomic problems in Aglaonema nitidum. The first problem involves the northwestern extremity of the distribution of the species. In that area the species appears to undergo several tendencies: smaller size, shorter petiolar sheath, loss of the scarious petiolar margin, membranous rather than a coriaceous texture, more ovate leaves with rounded leaf-bases, and fewer pistillate flowers. The plants of central Thailand, Cambodia, and South Vietnam are so strongly differentiated in these characters that they could be maintained as a distinct species, A. cochinchinense. The plants of southern Burma, however, show only enough differentiation to justify recognition as a variety, A. nitidum var. helferi. Further collections from southern Burma and western Thailand would be very desirable to clarify the complex.

The second problem involves the northeastern extremity of the species. In the Philippines there seems to be some overlapping with the A. philippinense-densinervium-stenophyllum-crispum complex. Some of the distinctive characters of A. nitidum (as opposed to other common species, such as A. simplex and A. marantifolium) are found in material from the Philippines, i.e., acute leaf base, long petiolar sheaths, and scarious sheath margins; however, these characters are either not in combination or, when they are, they are further combined with characters not at all typical of A. nitidum. This had led me to consider that the Philippine complex may have a hybrid origin in which A. nitidum, along with A. simplex and A. marantifolium, may have had a part. True A. nitidum, as known in Borneo, Malaya, and Sumatra, occurs in the Philippines only on Balabac Island (which is, incidentally, also the farthest penetration of the mouse deer [chevrotain] into the Philippines).