dcsimg

Comprehensive Description

provided by Smithsonian Contributions to Botany
Aglaonema pumilum

Aglaonema pumilum Hooker f., 1893, p. 530.

A. marmoratum Engler, 1915, p. 17.

Stem decumbent(?), often reddish, 0.3–0.5 cm thick. Internodes 0.3–1.3 cm long. Petioles 3.5–7.0 cm long, 0.3–0.7 times as long as the leaf-blade. Sheaths 1–3.5 cm long, 0.2–0.8 times as long as the petiole. Leaf-blades ovate to lanceolate, 8–13.2 cm long, 2.3–5.2 cm wide, length/width ratio 1:2–2.9; base often unequal, usually rounded, obtuse to truncate; apex gradually acuminate; variegation absent or ashy-blotched on the upper leaf surface; venation not or only weakly differentiated into 3–4 primary lateral veins diverging from midrib at 45°; texture rather coriaceous. Cataphylls frequent, interspersed with leaves, like brown paper, 3–4 cm long. Peduncle solitary, 3–5 cm long, often equaling the petiole. Spathe 2–4.5 cm long, 1–1.5 cm wide, decurrent for 0.4–1.0 cm. Stipe present(?). Spadix thin-cylindric, 0.8–2.0 cm short of spathe apex, 1.5–2.0 cm long; pistillate portion 0.2–0.4 cm long, pistils ca. 5; staminate portion 1–1.7 cm long, 0.2–0.3 cm thick. Fruits 1–1.5 cm long, 0.5–0.8 cm thick.

TYPE COLLECTION.—Burma Mergui, Griffith s.n. (lectotype: K); India, Assam, Lushai Hills, Chappedon, February 1827, Wallich, E. India Co. 8960B (syntype: not seen). There is some doubt about the identity of Wallich’s collection since the locality, Chapa Tong Hill, is about 700 miles away from what appears to be the range of A. pumilum. I was unable to find Wallich’s specimen at Kew, Calcutta, or any of the herbaria I visited. Since Griffith’s specimen is in fruit, Wallich’s specimen must be the basis of Hooker’s description of the spathe.

DISTRIBUTION.—Lower Burma and peninsular Thailand (Figure 6).

HABITAT.—In evergreen forest.

Among the Schottian drawings at Vienna, “Schott, Aroideae Nr. 68” is labelled “8900 Wallich Cat, Chappedong, Feb. 1827 Herb. Benth.” This label is incorrect. Study of Wallich, E. India Co. 8960A (not B) from Singapore clearly shows that this is the basis of “Schott, Aroideae Nr. 68.” This error is critical since Wallich, E. India Co. 8960A is the holotype of A. minus (A. nebulosum f. nanum herein).

The type of A. marmoratum is: Hort. Bot. Calcutta, 18 April 1896, Prain s.n. (holotype: CAL). Engler did not cite the collector’s name, but he did cite a specimen flowering in Calcutta in April 1896. This specimen meets those requirements and has been annotated by Engler as A. marmoratum. I can see no reason to maintain A. marmoratum, except perhaps as a variegated form of A. pumilum. In the original description of A. marmoratum, Engler (1915) commented: “Species imperfecte cognite et fortasse cum priore [A. pumilum], cujus inflorescentia ignota, conjugenda.” My studies indicate that Engler’s hypothesis is correct.

The relationships of this species are obscure. There is a possibility that it should be placed in the section Chamaecaulon in that it may be repent, there are cataphylls among the leaves, and it usually has very short petiolar sheaths; however, it may only be decumbent, the cataphylls do not clasp the petioles as they do in Chamaecaulon, and one specimen, Brown s.n., has sheaths 2–3.5 cm long. Gagnepain annotated the Thai collections as A. costatum var. virescens. The thin-cylindric spadix, however, much shorter than the spathe, is unlike that species.

There is also a possibility that the spadix is sessile and these is no stipe, indicating a possible relationship with A. modestum or A. ovatum; this seems rather dubious and Brown s.n. does not appear to have a stipe.
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bibliographic citation
Nicolson, Dan H. 1969. "A revision of the Genus Aglaonema (Araceae)." Smithsonian Contributions to Botany. 1-69. https://doi.org/10.5479/si.0081024X.1