Aglaonema hookerianum Schott

Aglaonema hookerianum

Aglaonema hookerianum Schott, 1859, p. 30.

A. clarkei Hooker f., 1893, p. 529.

Stem erect, 40–50 cm or more, 1.5–2.0 cm thick. Internodes 1.5–3.0 cm long. Petioles 14–24 cm long, 0.7–0.9 (1.2) times as long as the leaf-blade. Sheaths membranous, (4) 8–15 cm long, (0.2) 0.5–0.6 (0.8) times as long as the petiole. Leaf-blade ovate to elliptic or lanceolate to narrowly elliptic, 20–27 cm long (5.3) 7–12 cm wide, length/width ratio 1:2.0–2.9(3.8); base often unequal, rounded, obtuse or broadly acute, rarely acute; apex often apiculate, acuminate to gradually or suddenly long acuminate (acumen to 2.1 cm long from point of 1 cm blade width to apex); variegation none; venation weakly to strongly differentiated into 7–13 primary lateral veins which diverge from the midrib at (30°) 40°–50°. Peduncles 1–3 together, (6) 10–21 cm long. Spathe 3.7–6.0 cm long, decurrent for (0.6) 1–1.5 (2) cm. Stipe none. Spadix thin-cylindric, 2.5–4.0 cm long, equaling to 0.8 cm short of spathe apex; pistillate portion 0.3–0.6 cm long, attached to spathe, pistils ca. 10–15; staminate portion 2.0–3.7 cm long, 0.3–0.6 cm thick. Fruits red, large when ripe, (1.7) 2–3 cm long, (0.7) 0.9–1.4 cm thick.

TYPE COLLECTION.—India, Churra [Cherrapunji], 2000 ft, 15 June [18]50, Hooker and Thomson s.n. (holotype: K).

DISTRIBUTION.—Northeastern India, East Pakistan, and coastal western Burma (Figure 3).

HABITAT.—Below 1000 m, in deep shade of forest receiving more than 80 inches of annual rainfall.

FLOWERING TIME.—June–July, probably influenced by the onset of the summer monsoon.

Aglaonema hookerianum Schott, as indicated by the key to species, is very similar to A. modestum and A. ovatum. The primary differences between these species seem to be in the spadices. Most of the specimens available are in fruit; because of the paucity of flowering material, I am not certain just how distinctive these taxa are. Secondary considerations like plant size, leaf shape, and distribution were used for identification. Also, lack of collections from northern Burma and southwestern China made it impossible to know whether or not intergradations occur in the areas where they would be most expected. The distinctive characteristics of A. hookerianum are: (1) sessile spadix, (2) spadix equaling the spathe (3) large fruits, (4) a long peduncle (compared with A. ovatum and A. modestum), and (5) restriction to western Burma, southern East Pakistan, and northeastern India.

At one time it seemed to me justifiable to segregate Aglaonema ovatum, A. modestum, and A. hookerianum as a separate section of the genus because of their sessile spadices and northern distribution. The absence of any other distinguishing characters and the occasional occurrence of subsessible spadices in A. simplex, A. tenuipes, and A. cochinchinense made this segregation untenable.

The type of Aglaonema clarkei Hooker f. is: East Pakistan, Kaselong [Kaselang River], 10 Jan. 1869, Clarke 8266 (holotype: K). Aglaonema clarkei is similar to A. hookerianum with its large seeds, sessile spadix, and long peduncle. It differs primarily by its exceedingly short petiolar sheath and scandent habit. The report of scandent habit is surely an error for the reason that, although large plants of Aglaonema tend to recline against their neighbors, they are not climbers in the usual sense of the word. The short petiolar sheath is represented only by the one leaf on the type. Superficially the taxon resembles A. nitidum in its acute leaf-base and lack of differentiated venation, characters occasionally found in A. hookerianum (Prazer s.n. and Leslie 306). It seems best to regard A. clarkei as a probable synonym of A. hookerianum. The type-locality, on the Kaselang River, may now be drowned by the Karnaphuli Reservoir.