Heliamphora

The genus Heliamphora ( or ; Greek: helos "marsh" and amphoreus "amphora") contains 24 species of pitcher plants endemic to South America. The species are collectively known as sun pitchers, based on the mistaken notion that the heli of Heliamphora is from the Greek helios, meaning "sun". The name instead derives from the Greek helos, meaning "marsh", so a more accurate translation of their scientific name would be marsh pitcher plants. Species in the genus Heliamphora are carnivorous plants that consist of a modified leaf form that is fused into a tubular shape. They have evolved mechanisms to attract, trap, and kill insects; and control the amount of water in the pitcher. At least one species (H. tatei) produces its own proteolytic enzymes that allows it to digest its prey without the help of symbiotic bacteria.

==Morphology== All Heliamphora species are herbaceous perennial plants that grow from a subterranean rhizome. Heliamphora species form stemless rosettes and leaf height ranges from a few centimeters (H. minor, H. pulchella) up to more than (H. ionasi, H. tatei). Heliamphora possess tubular traps formed by rolled leaves with fused edges. Marsh pitcher plants are unusual among pitcher plants in that they lack lids (opercula), instead having a small "nectar spoon" on the upper posterior portion of the leaf. This spoon-like structure secretes a nectar-like substance, which serves as a lure for insects and small animals. Each pitcher also exhibits a small drainage hole (W, E2a, E2b, and E3 Clades) or slit (E1 Clade) in its side that allows excess rainwater to drain away, similar to the overflow on a sink. It was inferred that the drainage structure first evolved as drainage hole in ancestral Heliamphora populations and further modified into drainage slit in the ancestors of E1 clade. This allows the marsh pitcher plants to maintain a constant maximum level of rainwater within the pitcher. The pitchers' inner surface is covered with downward-pointing hairs to force insects into the pitchers' lower parts. The morphological diversification of Heliamphora pitchers is both convergent and divergent, likely as a result of adaptive radiation in the geographically complex Guiana highland. center|thumb|950x950px|Phylogeny of Heliamphora inferred from nuclear DNA and the evolution of morphological characters. The drainage slit is only found in the E1 clade. In the rest of Heliamphora, the drainage hole is present. The study suggested that the drainage hole is the ancestral state in Heliamphora and was further modified into drainage slit in the E1 clade. center|thumb|855x855px|'Adaptive Radiation of Heliamphora Pitchers' thumb|left|Illustration of Heliamphora nutans from [[John Muirhead Macfarlane's 1908 monograph on the genus (A: entire plant; B: androecium; C: stamen; D: pistil; E: transverse section of the ovary; F: seed, with the testa; G: vertical section of the seed; H: embryo)]]