Arophyton humbertii Bogner

CATE Araceae, 17 Dec 2011. araceae.e-monocot.org

Habitat

growing in a cluster in small pockets of humus on rocks of gneiss in very shaded places; only here and there on soil rich in humus in forest. (pH 5.4-5.8)

Phenology

Flowering in December to January; fruiting in January to February.

Diagnostic

Rhizomatous; leaf blade with up to 7 segments, green on the lower surface; length of the spathe 1.2 times the spadix; spadix free with a long appendix; no sterile flowers.

General Description

Perennial herb, rhizome creeping, 7-30 x 1.5-3.5 cm, dark brown outside, red inside; 1-2 leaves (up to 4 leaves in cultivation) with usually 2 inflorescences which succeeded by one or two leaves, inflorescences and leaves appearing simultaneously. LEAVES: Cataphylls acuminate, reaching 25 cm long, dirty green or slightly tainted red with small red-blackish mottling, withering later. Petiole cylindrical, 40-80 x 0.5-1.5 cm, dark green or slightly tainted with blackish-red; sheath relatively short, 3-8 cm long. Leaf blade pedate, ca.40 x 40 cm, with 7 dark green segments, paler on the lower surface, each segment a little decurrent along the rachis, the middle segment always bigger, the lateral segments small, the size decreasing gradually towards the outside, the rachis thus almost forming a circle, the outer segments opposite the middle segment; segments narrowly elliptic, acuminate at the apex, median 15-30 x 4-10cm; outer segments smaller, 11-16 x 2.5-4.5 cm, having at their base another lobe always directed towards the outside, these last one 2.5 x 1-3 cm, usually ± acute; midrib very well developed, more marked underneath; 6-10 primary lateral veins on each side; inner collective vein with a distance to the edge of the leaf of 0.5-1 cm; outer collective vein 1-2 mm to the edge; shapes in the juveniles ± hastate to tripartite with all shapes of leaves up to pedate; hastate leaves 7-8 x 6-7.5 cm. INFLORESCENCE: Peduncle 21-42 cm long and ca. 0.5 cm diameter, pale green, very weakly mottled red-blackish. Spathe linear acuminate to acute, 13-21 x 1.5-1.8 cm, rolled in a tube at the base, top part spreading, with red-blackish vertical lines at the base of the outer face, upper part dirty-white, inside dark purple at the level of the part enclosing the female flowers, dirty-white above. Spathe only very weakly narrowed at the level of the female zone of the spadix; spathe longer than the spadix, linear acuminate to cuspidate, 3-4 cm, desiccating completely during fruiting. Spadix entirely free, slender, 10-17 cm long, purple, with an appendix; male zone 4-9 cm long, ca. 4 mm diameter towards the base; female zone 1.5-2 cm long, ca. 6 mm diameter; appendix 3-6 cm long, subulate at the apex, ca.1 mm diameter at the apex; synandriums progressively more sparse towards the appendixm, and thecae of synandriums very remote from each other in the upper part of the male zone of the spadix; males and female parts directly superposed. Synandriums very narrowly elliptic, 2-3 times shorter at the base than towards the top of the spadix, 5-15 x 1.5 mm, much flattened, flat towards the top; only the lowermost synandriums in proximity to the female flowers have a narrow slit in the centre; 6-14 thecae scattered and sunken in the side of the synandrium, dehiscing via a pore; synandrium purple, thecae pale yellow; female flowers tall, ca. 2mm, appearing ± rhombic veiwed from above, ca. 3 x 2 mm; pistil surrounded by a cyathiform synandrium; syandrium a little angular, pale yellow; ovary ovoid, yellowish-green; ovule ± globose; funicle very short; style very short; stigma disc-shaped, 1.7-1 mm diameter, purple, with small white papillae. INFRUCTESCENCE: Berries elliptic, ca. 1cm long, 0.6 cm diameter in the center, red when fresh, provided with blackish vestiges of the stigma. Number of chromosomes 2n = 38