Sigmoid spider orchid facts for kids

The sigmoid spider orchid (scientific name: Caladenia sigmoidea) is a special kind of orchid that grows only in the south-west part of Western Australia. It's known for its unique red and cream-colored flowers. These flowers have a very unusual S-shaped part called a labellum, which helps give the orchid its name.

What Does the Sigmoid Spider Orchid Look Like?

The sigmoid spider orchid is a perennial plant, meaning it lives for many years. It's also a deciduous herb, which means its leaves fall off at certain times of the year, but it grows back from an underground tuber (a swollen stem that stores food).

This orchid has one tall, hairy leaf that is about 70 to 120 mm (3 to 5 inches) long and about 3 mm (0.1 inches) wide. Usually, only one flower grows on a stalk that is 50 to 150 mm (2 to 6 inches) tall.

Flower Details

The flowers are red and cream-colored, about 30 to 40 mm (1 to 2 inches) long and 20 to 30 mm (0.8 to 1 inch) wide. The sepals and petals are parts of the flower that look like petals. They have thick, brown, club-shaped tips that are 4 to 6 mm (0.16 to 0.24 inches) long. These tips are called glandular tips because they might produce a sticky substance.

• The dorsal sepal (the one at the top) stands straight up. It is about 15 to 20 mm (0.6 to 0.8 inches) long and 1 mm (0.04 inches) wide.
• The lateral sepals (the two on the sides) are also 15 to 20 mm long and about 2 mm (0.08 inches) wide. They curve stiffly downwards.
• The petals are 15 to 20 mm long and about 1 mm wide. They curve stiffly upwards.

The most interesting part is the labellum, which is like a landing pad for insects. It's 8 to 10 mm (0.3 to 0.4 inches) long and 5 to 6 mm (0.2 to 0.24 inches) wide. It's creamy white with red stripes. The sides of the labellum have up to six small teeth on each side. There are also two rows of red, anvil-shaped bumps called calli along its middle.

The labellum has a very unusual shape: it curves downwards, but its tip then turns back up. This creates a clear S-shape when you look at it from the side. This orchid usually flowers from August to September.

How Did It Get Its Name?

The sigmoid spider orchid was first officially described in 1938 by a person named Richard Rogers. He found a sample of the plant near a place called Kumarl, close to Salmon Gums.

The scientific name, sigmoidea, comes from a Latin word, sigmoideus. This word means "curved like the letter S." This name was chosen because of the orchid's unique S-shaped labellum.

Where Does This Orchid Live?

The sigmoid spider orchid is found in many places between Mount Jackson and Mount Ragged in Western Australia. It grows in different types of areas, including:

• Stony hills
• Woodlands
• On granite outcrops (large rocks sticking out of the ground)

These areas are part of what scientists call the Avon Wheatbelt, Coolgardie, and Mallee biogeographic regions.

Is This Orchid Safe?

The Western Australian Government's Department of Parks and Wildlife has looked at the sigmoid spider orchid. They have classified it as "not threatened." This means that, for now, there are enough of these orchids, and they are not considered to be in danger of disappearing.