Adenia metamorpha Photo by: © Plantemania
Origin and Habitat: Adenia metamorphaSN|35235]]SN|35235]] is known from only one locality in Madagascar in the Ankarana Reserve, in the trail between Campement des Anglais and Lac Vert.
Altitude range: around 130 metres above sea level.
Habitat and ecology: This species grows among limestone rocks in seasonal tropical forest. The larger tubers are generally subterranean, but can be partially exposed in rocky areas with shallow soils. Adult plants are relatively rare.
Synonyms:
Description: Adenia metamorphaSN|35235]]SN|35235]] is a glabrous and dimorphic species that undergo a remarkable transformation. For several years it is a low geophytic plant with a large underground storage tuber (caudex) that allow plants to survive unfavorable weather conditions, then a transition to a vining habit take place and after several years the adults develop a thin cylindrical trunk. Leaves vary between having five lobes mottled white and green to being unlobed, cordate and green. This transformation in leaf shape can occur along a single stem. Adenia metamorphaSN|35235]]SN|35235]] is the only Madagascan Adenia with a narrow cylindrical trunk and large napiform tuber.
Derivation of specific name. The name “metamorpha” is suggestive of the radical metamorphosis in leaf shape and plant habit.
Tuber: Up to to 30 cm in diameter, napiform, smooth and occasionally fissured, subterranean or partially above ground.
Trunk: Cylindrical, up to 2 m tall, less than 5 cm in diameter.
Annual stems: Emerging from trunk annual, thin, climbing to 10 m long, with 7-13 cm long simple tendrils.
Leaves: membranous, with patchy white and green marks and often somewhat transparent as juveniles, uniformly green as adults. Petiole 2-4 cm long. Blade of mature leaf heart-shaped to triangular, 4-12 cm long 3-8 cm wide, margin entire, recurved, unlobed or 2- to 3-lobed. juvenile leaves deeply 5-lobed with lobules cut into deep irregular usually pointed fringes. Stipules small, hardening with age, triangular.
Inflorescences: Subtended by tendrill 1-3 flowered. Bracts and bracteoles
triangular. Female flowers funnel shaped 9 mm long.
Fruits: 8 cm long, 2 cm in diameter, spindle-shaped to ellipsoid, leathery, smooth to weakly reticulate.
Seeds: (20-30 per pods) ovate, 5-7 mm long, 4-5.5 mm wide, 2.5-3.5 mm thick with 40-70 raised warts.
Bibliography: Major references and further lectures
1) Hearn DJ (2007) "Novelties in Adenia (Passifloraceae): Four new species, a new combination, a vegetative key, and diagnostic characters for known Madagascan species". Brittonia 59(4): 308-327.