Paracaleana
| Paracaleana | |
|---|---|
 |
|
| Small duck orchid (Paracaleana minor) | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Diurideae |
| Subtribe: | Drakaeinae |
| Genus: |
Paracaleana Blaxell (1972) |
| Type species | |
|
Paracaleana minor |
|
Paracaleana commonly known as duck orchids, is a genus of flowering plants in the orchid family, Orchidaceae that is found in Australia and New Zealand. The Australian species are found in all states but have not been recorded in the Northern Territory. Orchids in this genus are similar to Caleana major, but there are differences in the flowers and in the insects that pollinate them. Paraceleana orchids, as well as hammer orchids (Drakaea) are pollinated by male thynnid wasps. Duck orchids have a single leaf and one or a few, dull-coloured, inconspicuous flowers.
Orchids in the genus Paracaleana are terrestrial, perennial, deciduous, sympodial herbs usually with a few inconspicuous, fine roots and a dark red, oval-shaped, tuber. Replacement tubers called "droppers" form at the end of long root-like stolons. A single leaf 1–4 cm (0.4–2 in) long develops near the base of the plant during the growing season and withers late in the flowering season. The leaf is linear to heart-shaped, dark green above with maroon lines and markings and is dark maroon below.
The flowering stem is wiry, dull brownish maroon and bears one to a few flowers each on a stalk 5–20 mm (0.2–0.8 in) long, each with a small leaf-like bract. The flowers are non-resupinate and . The sepal and the two petals are similar in size and are narrow linear in shape with pointed or club-shaped ends. The dorsal sepal points downwards and is pressed against the column. The sepals and two petals usually spread obliquely downwards and sideways. The dorsal sepal and petals are attached to the base of the column where it joins to the ovary. As is usual in orchids, one petal is highly modified as the central labellum. Duck orchids have an unusual, insect-like labellum which flicks over when touched. The labellum is attached to the column by a flexible "claw" which bends under the weight of a pollinating wasp. The labellum is flask-shaped, narrowing near the end with the narrow end covered with small raised calli or glands which are usually black, but may be maroon or greenish. In some species the calli may cover a greater part, or even all of the labellum (as in P. minor). Glands on the labellum emit pheromones which are sexual attractants for male thynnid wasps. The sexual parts of the flower are fused to the column which has broad wings along its length, forming a cup-like basket. Flowering occurs in spring in most species and is followed by the fruit which is a non-fleshy, dehiscent capsule containing up to 500 seeds.
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