THE GREENHOOD GROUP

Every greenhood is a form of temporary trap, to an unsuspecting insect visitor, with either a spring-loaded or counter-balanced door.

The spring-loaded door is the highly irritable labellum which often has bristles or hairs (see photo a) to block any escape route other than past the column.  The labellum reaction is fast and immediate. (see photo c)

The counter-balanced door closes off the escape route just as efficiently, although more slowly, and is dependant on the insect crawling towards the base of the labellum. (see photos b & d)

Reset of the labellum can be from 25 minutes to more than 3 hours on warm days and double that in cooler temperatures.  Time variance depends on the species.

Pollination visits last 30 - 90 seconds, regardless of the amount of time needed to reset the labellum.

The dorsal sepal has united with the two adjacent petals to form a cap or hood which shelters the column and labellum.

Light thrown through the clear crystalline panels in the hood may attract insects.  (see photo left)

Pheromone-like perfume and/or an insectiform labellum may attract insects in which pseudocopulation is a factor.

There may even be an addictive 'liquor' in the tissues at the base of the labellum which acts as the insect attractant.

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