The two orchids that I have chosen to feature this month belong to the Tiny Greenhood group of Pterostylis.
Flowering in autumn, the flowers are very small, and thus the orchids are often overlooked in amongst the grasses of the open forest areas and heathy woodlands. They sometimes form a loose colony around the base of eucalypts.
Pterostylis parviflora (parvus-small, flora-flower) has the smallest flowers in the greenhood genus within the Anglesea district – they are just 9 mm long. Up to 6 green and white striped, well-spaced flowers tend to face towards the stem, which can grow up to 25 cm tall. The hood curves over the upright flower, and ends in a blunt tip.
The short lateral sepals protrude where they join the flower, forming a swollen bottom lip. They are erect, and usually do not protrude above the hood. The tip of the labellum may just be seen through the frontal opening. Each plant may have up to 3 rosettes of pointed, stalked leaves that develop beside the flowering stem, often after flowering has commenced. They do not encircle the stem. Non-flowering plants also form rosettes.
Pterostylis sp. aff. parviflora (Southern Vic) Brown-tipped Greenhood is still waiting for a name of its own – aff. parviflora indicates that it is an unamed species similar to Pterostylis parviflora. In spite of the many similar characteristics, these two Greenhoods can be easily distinguished.
The flowers of the Brown Tipped Greenhood also face toward the stem, but are slightly larger – up to 10 cm long – and the petals and sepals have reddish-brown tips.
The tips of the the flowers also extend slightly further than those of P. parviflora, and are gently upturned. The short, lateral sepals tend to curve in line with the hood. They do not form a swollen bottom lip. The flower stem can grow up to 30 cm tall.
Although the conditions are still very dry, other orchids are starting to appear – a few Autumn Bird Orchids Chiloglottis reflexa, and a few Mosquito Orchids Acianthus pusillus. Rosettes of Nodding Greenhoods Pterostylis nutans are appearing in large numbers in many areas, and some Tall Greenhoods P. melagramma are in bud.
Hopefully the recent long-awaited autumn rains will make a difference!
Photos and descriptions of all the orchids that grow in the Anglesea district are documented in Orchids of the Anglesea District available from ANGAIR.