Aglaonema ovatum Engl.

Aglaonema ovatum f. maculatum Nicolson

Aglaonema ovatum var. maculatum Gagnepain 1942, p. 1130 [without Latin diagnosis].

A forma ovato foliorum laminis irregulariter cinereomaculatis differt.

Leaf-variegation of scattered ashy blotches about 1 cm square, these frequently irregularly confluent; venation weakly differentiated into 6–8 primary lateral veins diverging from the midrib at 50°. Peduncles 1 or 2, 8–10 cm long, over half the petiole. Spathe decurrent for 1 cm.

TYPE COLLECTION.—Thailand, Petchabun, Ta Luang, 200 m, evergreen forest, 5 March 1931, Kerr 20370 (holotype: K; isotypes: K).

This form is known only from a single fruiting collection that shows no evidence of a stipitate inflorescence. Its locality and vegetative characters indicate that it belongs with A. ovatum rather than with A. modestum or A. hookerianum. It was called A. ovatum var. maculatum Gagnepain (1942, p. 1130), but this name was invalidly published without a Latin description.

Aglaonema ovatum

Aglaonema ovatum Engler, 1898, p. 21.

Stem erect, 0.5–1.5 cm thick. Internodes 0.7–3.0 cm long. Petioles (5) 8–14 (18) cm long, (0.3) 0.5–0.8 (1.1) times as long as the leaf-blades. Sheath membranous, (1.5) 3–8 cm long, (0.3) 0.4–0.6 (0.7) times as long as the petiole. Leaf-blades ovate to lanceolate, rarely elliptic, (10) 13–21 (26) cm long, (3) 5–10.5 cm wide, length/width ratio 1: (1.7) 2–3(5.5); base rounded to obtuse, rarely subcordate; apex often apiculate, acuminate (acumen 1.0–2.8 cm from point of 1 cm blade width to apex); rarely variegated with scattered blotches; venation weakly to strongly differentiated into 5–10 primary lateral veins diverging from the midrib at 35°–60°. Peduncles 1–2 together, 3.5–7.0 (10) cm long, usually about ½ as long as the petiole. Spathe 3.5–4.7 cm long, decurrent for 0.4–1.5 cm. Stipe none. Spadix cylindric, 3.0–4.3 cm long, usually exceeding spathe but sometimes 0.5 cm short of spathe apex; pistillate portion 0.4–1.6 cm long, pistils ca. 10–20; staminate portion 2.8–3.5 cm long, 0.6–1.0 cm thick, with lower 0.5 cm sterile and distinctly differentiated in color and size from the fertile area. Fruits red, 1.1–2.0 cm long, 0.7–1.0 cm thick.

DISTRIBUTION.—Northern continental Southeast Asia (Figure 4).

HABITAT.—In evergreen forest along streams or in shaded and humid places.

FLOWERING TIME.—April–May (July), probably influenced by the onset of the summer monsoonal rains (March–April).

This species is most closely related to Aglaonema hookerianum and A. modestum. It is distinguished by having the spadix equaling or exceeding the spathe and by rather strongly differentiated staminodia between the pistillate and staminate flowers. Fruiting specimens can be distinguished from A. hookerianum by their shorter peduncles. Fruiting and sterile specimens cannot be satisfactorily distinguished from A. modestum. The leaves of A. modestum are very longacuminate (acumen over 2.5 cm long from point of 1 cm blade width to apex), a condition not attained in A. ovatum; however, flowering material of A. modestum from Laos lacks the extremely long acumen. It is hoped more and better flowering material may provide the means of recognizing better vegetative characters.

It should be noted that Aglaonema tenuipes occasionally has subsessile spadices and differentiated staminodia, suggesting possible confusion with A. ovatum. I am not certain that all fruiting or sterile specimens can be satisfactorily separated from A. tenuipes.