Summer greenhood (Pterostylis decurva)
Description
Pterostylis decurva, commonly known as the summer greenhood, is a species of orchid endemic to south-eastern Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants have a single flower with leaves on the flowering spike. This greenhood usually flowers in summer and has a white flower with green stripes and a brownish tinge. It is similar to P. aestiva but has paler green flowers. Pterostylis decurva is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of two to five leaves often held above the ground on a stalk up to 100 mm long. Each leaf is oblong to egg-shaped, 10-30 mm long and 10-20 mm wide. Flowering plants have a single flower 18-25 mm long and 7-9 mm wide borne on a spike 150-300 mm high with four or five stem leaves. The flowers are white with green stripes and a brown tinge in the galea. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal curves forward, often downwards, with a thread-like tip 15-20 mm long. The lateral sepals are held closely against the galea, have an erect, thread-like tip 30-40 mm long and a broad, slightly protruding, U-shaped sinus between their bases. The labellum is 12-15 mm long, 2.5 mm wide, brown, blunt, and curved and protrudes above the sinus. Flowering occurs from October to March.
Taxonomic tree
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Domain: Eukarya
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Kingdom: Plantae
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Phylum:
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Class: Liliopsida
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Order: Asparagales
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Family: Orchidaceae
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Genus: Pterostylis
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