Duck orchids facts for kids
Quick facts for kids Duck orchids |
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| Large duck orchid (Caleana major) | |
Scientific classification  |
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Subfamily: | Orchidoideae |
| Tribe: | Diurideae |
| Subtribe: | Drakaeinae |
| Genus: | Caleana R.Br., 1810 |
| Type species | |
| Caleana major R.Br.
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| Synonyms | |
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Caleana, also known as duck orchids, is a group of unique flowering plants. They belong to the orchid family and are found in Australia and New Zealand. These orchids get their name because their special flower part, called the labellum, looks like a duck's head.
Most duck orchids grow in Western Australia. However, one type, C. major, lives in eastern Australia. Another type, C. minor, is found in both eastern Australia and New Zealand. These amazing plants have a very clever way of getting pollinated by male thynnid wasps.
Contents
What do Duck Orchids Look Like?
Duck orchids are plants that grow in the ground. They come back every year and lose their leaves during certain seasons. They have small, fine roots and a dark red, oval-shaped underground storage part called a tuber. New tubers can grow from long, root-like stems called "droppers."
A single leaf grows near the base of the plant. It is usually 1 to 4 centimeters (about 0.4 to 1.6 inches) long. This leaf is folded lengthwise and often has purple markings. It appears during the growing season and then dries up later.
The stem that holds the flowers is thin and brownish-red. It usually has one to a few dull-colored flowers. Each flower grows on a small stalk, about 5 to 20 millimeters (0.2 to 0.8 inches) long. There's also a small leaf-like part called a bract near each flower.
The Unique Duck Orchid Flower
Duck orchid flowers are very special. They have three main parts that look like petals:
- The top part, called the dorsal sepal, points downwards.
- The two side parts, called lateral petals, usually spread out sideways and downwards.
The most amazing part is the labellum. This is a highly changed petal that looks like an insect. It's attached to the rest of the flower by a sensitive stalk. This stalk holds the labellum up, ready for a visitor.
The flower also has a "column" with wide parts that look like wings. When a wasp lands on the labellum, the labellum quickly flips down. This traps the insect between the labellum and the column wings. This way, the insect touches the parts of the flower that hold pollen. The labellum itself is shaped like a flask and has small bumps or glands. These glands release special scents called pheromones. These scents act like a perfume, attracting male thynnid wasps.
Most duck orchids bloom in spring. After flowering, they produce a dry seed pod called a capsule. Each capsule can hold up to 500 tiny seeds.
How Duck Orchids are Named and Classified
The group of plants called Caleana was first officially described in 1810 by a botanist named Robert Brown. He published his description in a book called Prodromus Florae Novae Hollandiae et Insulae Van Diemen. The name Caleana was chosen to honor George Caley.
Scientists have had some discussions about how Caleana is related to another group called Paracaleana. Some studies suggest they are very similar and might even be the same group. However, some plant experts still consider them separate.
Types of Duck Orchids
Here is a list of the different types of Caleana orchids known as of April 2018:
- Caleana alcockii – Alcock's duck orchid (Western Australia)
- Caleana brockmanii – Brockman's duck orchid (Western Australia)
- Caleana disjuncta – little duck orchid (Western Australia, South Australia, Victoria)
- Caleana dixonii – sandplain duck orchid (Western Australia)
- Caleana gracilicordata – slender-leafed duck orchid (Western Australia)
- Caleana granitica – granite duck orchid (Western Australia)
- Caleana hortiorum – Hort's duck orchid (Western Australia)
- Caleana lyonsii – midget duck orchid (Western Australia)
- Caleana major – large duck orchid (New South Wales, Queensland, South Australia, Tasmania, Victoria)
- Caleana minor – small duck orchid (New South Wales, Queensland, South Australia, Tasmania, Victoria, North Island of New Zealand)
- Caleana nigrita – flying duck orchid (Western Australia)
- Caleana parvula – Esperance duck orchid (Western Australia)
- Caleana terminalis – smooth-billed duck orchid (Western Australia)
- Caleana triens – broad-billed duck orchid (Western Australia)
Where Duck Orchids Live
Duck orchids in Western Australia often grow in sandy soil. You can find them near areas that become wet and swampy in winter. They sometimes grow alongside other orchids like hare orchids (Leporella) and hammer orchids (Drakaea).
The large duck orchid (Caleana major) and the small duck orchid (Caleana minor) live in eastern Australia. C. minor also grows in New Zealand. These orchids prefer woodlands, damp heath shrublands, and grasslands. Sometimes they can be found on rocky slopes, in gravelly soil, or even along the edges of roads.
How Duck Orchids Reproduce: A Clever Trick
Duck orchids have a fascinating way of getting pollinated. Male thynnid wasps are tricked into helping the orchids reproduce. The flowers release special scents (pheromones) that attract these male wasps. The wasps think the labellum is a female wasp and try to mate with it.
When a wasp lands on the labellum, the labellum quickly flips down. This traps the wasp against the column of the flower. If the flower hasn't been visited before, sticky pollen packets (called pollinia) will attach to the wasp's back.
When this same wasp visits another duck orchid and gets trapped again, the pollen it carried will rub off onto the new flower's stigma. This process pollinates the second flower, allowing it to produce seeds. It's a very clever trick by the orchid to ensure its survival!
Images for kids
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Labelled diagram of Caleana nigrita
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