Scarce Marsh Helleborine

Description:

This helleborine is a perennial herb and grows, from a fleshy rhizome, to be between 25 – 150 cm tall. The leaves are ovate and pointed at both ends. They grow along the stem and can be 8 – 25 cm long. The inflorescence grows atop an erect stem. The flowers are fairly open and are green to yellowish-green in color with purplish or reddish radial stripes. The lip, or bottom middle petal, is tipped in white. The upper part of the stems, bracts, ovaries, and sepals are covered in short, fine hairs.

Habitat:

desert oasis

Notes:

Like all orchids, this helleborine is dependent on a mycorrhizal symbiosis, a mutually beneficial relationship between a plant and a fungus, to complete its life cycle. The Scarce Marsh Helleborine employs a trick, a special mimicry, to lure pollinating hoverflies to its flowers. The flowers emit three chemical substances that are usually released as alarm pheromones among aphids. Aphids are the preferred diet of hoverfly larvae. So female hoverflies smell these chemicals, interpret this to mean that aphids are nearby, and proceed to lay their eggs near the source of the scent – the flowers. The hoverflies are rewarded with a small sip of nectar, but their larvae are doomed to starve because, when they hatch, there will be no aphids around to consume. (This is a strange contradiction from an evolutionary perspective because since the larvae die, the number of potential pollinators decreases.)