The Nodding Greenhood, Pterostylis nutans, is one of Victoria’s most common terrestrial orchids. (Pteron = winged, stylos = pillar or column, nutans = nodding or drooping). The Nodding Greenhood is an abundant and widely distributed species. It usually flowers from mid-winter to late spring, depending on local and seasonal conditions.
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| Typical Nodding Greenhood colony |
Nodding Greenhoods are often found in a variety of habitats; sandy-rocky, moist-dry, etc., but nearly always shady. Sometimes they may only be a few centimetres tall, or you might come across some as tall as 10-20cms or more.
All native terrestrial orchids are a highly evolved plant species that have a symbiotic relationship with other plants, fungi and insects. Consequently, terrestrial orchids play a significant role in determining the ecological importance of a particular habitat and their presence - or not - can be an important indicator of the health of an ecosystem.
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| Ground-hugging leaf rosette |
Nodding Greenhoods die down through summer and their ground-hugging leaves, stems and flowers completely disappear. Their energy though is stored within underground tubers, and come next winter, they begin to appear above ground again, ready for the next stage of their evolvement.
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| Showing the labellum with hairs |
Most pterostylis species depend on a fungus gnat for their pollination and fertilization. The insect is lured to the orchid flower by a pheromone where it is momentarily trapped within the hood by the labellum ‘snapping’ upwards. Pollen is transferred to the insect as it struggles to escape. Upon release, the gnat flies to the next flower, so transferring the packets of pollen it has inadvertently collected, ensuring healthy cross fertilization of the plants.
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| Unusual double-headed flower |
While checking the nest boxes (5x Ringtails, 1x Kreft’s Glider and 1x Antechinus - we think) at the Golden Whistler Reserve in Drouin recently, the ‘bird nerd’ team ticked about a dozen colonies of Nodding Greenhoods with probably a total of several hundred plants in flower – including a rare ‘double-header’.