Dracontium polyphyllum L.

Global description

Dracontium polyphyllum is a stemless geophyte species, consisting of a large tuber and a single large leaf emerging directly from the ground by a long vertical petiole, a large part of which is underground. At the top of the petiole the leaf blade unfolds into 2 large horizontal umbrella-like lobes, each lobe being itself multi-lobed. The flower, which develops before the leaf, emerges directly from the ground on a short peduncle. It consists of a large spathe rolled into a vertical tube, the upper half of which is inclined and open at the side. It is dark purple in colour. In the centre of the spathe is a cylindrical spadix with a narrower, purple top.

General habit

Dracontium polyphyllum is a stemless herbaceous ground plant, consisting of a large flower emerging from the ground, which is then replaced by a large single leaf emerging from the ground at the end of a long vertical stalk. The leaf is up to 150 cm high and 150 cm in diameter.

Underground system

Tuber hemispherical or rounded, 6-10 cm diameter, 5-8 cm thick, flat above, rounded and white to brown below, 5-15 cm below ground level; secondary tubers few, cylindrically elongated or irregularly shaped, 0.5 cm diameter, 1 cm long, borne on the periphery of the main tuber. Roots fasciculate white, up to 0.3 cm in diameter.

Stem

No stem

Leaf

Cataphylls 3-5, 3-16 cm long and 1-2 cm wide, light brown, reaching or exceeding ground level. Leaf solitary or sometimes two or more per tuber, emerging directly from the ground. Stalk 1-2 m long above ground, 2-3.5 cm in diameter in the middle, dark green or brown-green, contrastingly spotted with dirty white or pale green spots and forming a reptilian pattern, usually smooth in the upper half and with irregular protuberances in the lower half. The juvenile blade is sagittate or sagittate-lobed. The mature blade is horizontally spreading, 0.8-1m in diameter, papery, sometimes fenestrated, sometimes variegated, sometimes with abundant raphid cells. It is shiny and dark green on the upper side, semi-glossy and medium green on the lower side. The first median division produces two trichotomous branches, 50-80 × 50-75 cm, the terminal subdivision consists of three sections. Each basal subdivision consisting of many segments; lateral divisions with two dichotomous branches, 50-80 × 45-70cm, terminal subdivision consisting of two sections, basal subdivision consisting of many segments; terminal and subterminal sections confluent or free, each consisting of a few segments or each consisting of many segments; Terminal leaf segments two- or three-lobed, broadly oblanceolate, more than 5 cm wide on each side of the main veins, oblanceolate or elliptic, at least some of the basal segments free from each other, often with contrasting smaller rounded or triangular segments alternating with larger ones. The tops of the segments are wedge-shaped or acuminate. Rachis patterned similarly to the petiole but in much paler tones, sometimes with spiny projections. Tertiary veins dark above and weakly raised below.

Inflorescence

The inflorescence is solitary or rarely in pairs, appearing before the new leaf. It is borne on a stalk 5-18cm long above ground, 0.5-0.8cm in diameter in the middle, often almost entirely subterranean (less than 10cm above ground), scarcely spotted, grey or whitish green, with very faint irregular protuberances. Bracteoles 3 or 4, 6-18 × 1. 5-2cm, dark brown to pink, the longest ± as long as or shorter than the stalk, covering up to 1/3 of the spathe. The spathe 6-12 cm long, 3-5 cm wide is cymbiform, cucullate, arched at 45 degrees, with an acuminate apex. The inner surface is semi-glossy, violet-purple, with an obvious translucent zone, 0. 5-1cm high, shorter than the spadix. The outer surface is brown, tinged with green, matt. The margin is entire or sometimes wrinkled, barely or slightly overlapping at the base. The veins are obscure to conspicuous on the inside, distinctly darker or paler than the purple spathe. The spadix is exposed, stipate, cylindrical, narrower at the apex, purple, 2.5-4.2cm long and 1-1.2cm diameter at anthesis, never with appendages at the apex. The stipe 0.5-0.8cm long, 0.4-0.8cm in diameter at anthesis, is pale green or light brown.

Flower

The flower consists of 4-5 (6) tepals 2-4 mm long and 1-2 mm wide, violet or light brown; 5 or 6-7 stamens with filaments 2-3 mm long and anthers 1-2 mm long. The ovary is 3-locular or rarely 4-locular, light green with a style 0-2 mm long above the tepals, violet, persistent and a 2-lobed or often 3-lobed stigma.

Fruit

The infructescence with the spadix is 5-16cm long and 3-4cm in diameter. The fruit is a 3-seeded berry, 0.5-0.7cm diameter and 1-1.5cm thick, subglobose, 3- to 6-angular, apically subtruncate. The young berry is pale green, the mature berry is greenish purple.

Seed

The seed, 0.5-0.7cm in diameter is kidney-shaped, light brown, laterally raised; dorsal ridges evident, 1, continuous, with the central ridge contrasting, over 1mm thick, 0.5-1mm high, warty on both sides, appearing as strongly reduced lateral ridges. 

Worldwide distribution

Dracontium polyphyllum only occurs in Suriname, French Guiana, Venezuela and northern Brazil.

https://www.gbif.org/species/5330699