Aglaonema vittatum Ridl. ex Engl.

Aglaonema vittatum

Aglaonema vittatum Ridley ex Engler, 1915, p. 33.

Stem 10–15 cm tall, 0.2–0.7 cm thick in dried material. Internodes 0.4–1.4 cm long. Petioles 2–4.2 cm long, 0.3–0.6 times as long as the leaf-blade. Sheaths 0.8–1.2 cm long, 0.2–0.4 times as long as the petiole. Leaf-blade lanceolate, 6.5–10.5 cm long, 1.7–3.0 cm wide, length/width ratio 1: (2.6)3–4.4; base often unequal, obtuse; apex gradually attenuate; variegation none or in form of a narrow central white stripe along the midrib; venation differentiated into 2–3 primary lateral veins diverging from the midrib at 30°. Peduncle solitary, 2.5–3.0 cm long (4–5 cm, fide Engler, 1915). Spathe 2–3 cm long, decurrent for 0.3–0.5 cm. Stipe 0.1–0.4 cm long. Spadix clavate, about half the spathe length (fide drawing at Kew); pistillate portion with ca. 10 pistils. Fruits red.

TYPE COLLECTIONS.—Indonesia, Lingga, Batu Gajah, 1–2000 ft, 19 July 1893, Hullett s.n. (lectotype: SING); Indonesia, Sungei Kelantan, Siak, November 1897, Ridley s.n. (syntype: SING).

DISTRIBUTION.—Restricted to eastern Sumatra and the Lingga Archipelago (Figure 6).

HABITAT.—In primary rain forest from a few meters above sea level (Buwalda 6629) to 300–600 m (Hullett s.n.).

FLOWERING TIME.—July–August on the few specimens available. Seasonality is not expected since all collections are from lowlands and within one degree of the equator.

Some of the collections show no evidence of the white midrib. Teysmann s.n. (BO 100514) is made up of four plants; two are variegated, one is not, and I am uncertain about the fourth. Biinnemeijer 7161 is variegated and Biinnemeijer 7173 is not although both were collected the same day, at the same elevation, and in the same locality.

Aglaonema vittatum is most similar to A. rotundum, judging by the unpublished drawings of the inflorescence at Kew. It resembles A. nebulosum in its short petiole and sheath but differs by its much narrower leaf.