Prasophyllum
| Leek orchids | |
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| P. elatum (tall leek orchid) at Strettle Road Reserve Glen Forrest | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Diurideae |
| Subtribe: | Prasophyllinae |
| Genus: |
Prasophyllum R.Br. (1810) |
| Type species | |
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Prasophyllum australe R.Br. |
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| Synonyms | |
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Prasophyllum commonly known as leek orchids, is a genus of about one hundred species of flowering plants in the orchid family, Orchidaceae and is found in Australia and New Zealand. The Australian species are found in all states but have not been recorded in the Northern Territory. The common name arises from their having a hollow, leek- or onion-like leaf. Some species only flower after summer fires and have flowers similar to those of Xanthorrhoea which flower at the same time, suggesting that they employ the same pollinating insects. Leek orchids are similar to those in the genus Genoplesium except that the free part of the leaf is cylindrical (flat in Genoplesium) and the labellum has a solid (rather than flexible) connection to the column. They range in size from the little laughing leek orchid (P. gracile) at about 15 cm (6 in) to the king leek orchid (P. regium) which grows up to 2 m (80 in) tall.
Orchids in the genus Prasophyllum are terrestrial, perennial, deciduous, sympodial herbs usually with a few inconspicuous, fine roots and a pair of more or less spherical tubers partly covered by a fibrous sheath. Replacement tubers form at the end of short root-like stolons. Leek orchids rarely reproduce by forming "daughter" tubers, relying on their flowers for reproduction. A single onion-like leaf develops near the base of the plant. The leaf is long, narrow, hollow, cylindrical and .
The inflorescence is a spike or raceme with a few to many non-resupinate flowers breaking through a thin part of the leaf. The sepal is wider than two sepals which are often joined. The petals are often curved, shorter and narrower than the sepals. As is usual in orchids, one petal is highly modified as the central labellum, differing markedly from the other petals and sepals. The labellum is positioned above the column and rigidly attached to its base. It edges are usually wavy and rolled back. The labellum has a callus which consists of a raised, fleshy plate which is usually channelled, with the base forming an inverted basin shape. The sexual parts of the flower are fused to the column which is short and has narrow wings, often with a small lobe at the front. Leek orchids usually flower between late winter and early summer, depending on species, and the fruit that follows flowering is a non-fleshy, dehiscent capsule containing up to 500 seeds.
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Wikipedia