Robust snail orchid facts for kids

The robust snail orchid (scientific name: Pterostylis dilatata) is a special type of orchid that only grows in the south-west part of Western Australia. This means it's endemic to that area, found nowhere else naturally!

When this plant is not flowering, it has a flat group of leaves called a rosette. But when it's ready to bloom, it grows a single green and white flower on a tall stem. These unique flowers usually appear in winter. They have special parts called lateral sepals that almost close up the front of the flower, making it look a bit like a snail.

What Does the Robust Snail Orchid Look Like?

The robust snail orchid is a perennial plant, meaning it lives for more than two years. It's also a deciduous herb, so its leaves fall off at certain times of the year. It grows from an underground tuber, which is like a small storage root.

When the plant is not flowering, it has a flat group of leaves, like a small circle, that lies on the ground. When it's time to flower, the plant doesn't have this leaf circle. Instead, it grows a single green and white flower on a stem that can be about 50 to 150 mm (2 to 6 inches) tall. This stem also has three to five small leaves, which are about 4 to 20 mm (0.2 to 0.8 inches) long and 1 to 4 mm (0.04 to 0.2 inches) wide.

The flower itself is quite striking, measuring about 18 to 24 mm (0.7 to 0.9 inches) long and 6 to 8 mm (0.2 to 0.3 inches) wide. The top part of the flower, called the dorsal sepal, and the petals form a hood over the central part of the flower. The petals spread out a bit, and the dorsal sepal has a short, pointed tip.

The lateral sepals stand upright and are joined together for most of their length. Their tips are thin and thread-like, about 11 to 15 mm (0.4 to 0.6 inches) long. These sepals are very close to each other and have a bulging area between them. Inside the flower, there's a small lip-like part called the labellum, which is about 6 mm (0.2 inches) long and 2 mm (0.08 inches) wide. You usually can't see the labellum from outside the flower. These orchids bloom from May to August.

How Did It Get Its Name?

The robust snail orchid was first officially described in 1984 by a botanist named Alex George. He found a specimen of the plant near a place called Bluff Knoll. The description was then published in a science journal called Nuytsia.

The second part of its scientific name, dilatata, comes from a Latin word. It means "spread out," "enlarged," or "extended." This name was chosen because of the flower's swollen or "bloated" base.

Where Does the Robust Snail Orchid Live?

The robust snail orchid grows in different types of natural areas, including shrubland and woodland. You can also find it in small pockets of soil on granite rocks. It lives in a wide area of Western Australia, stretching from Geraldton in the north to Israelite Bay in the south.

This orchid is found across several important natural regions, including the Avon Wheatbelt, Esperance Plains, Geraldton Sandplains, Jarrah Forest, and Swan Coastal Plain. These areas are part of Australia's special biogeographic regions.

Is the Robust Snail Orchid Safe?

Good news! The robust snail orchid (Pterostylis dilatata) is currently considered "not threatened." This classification comes from the Government of Western Australia's Department of Parks and Wildlife, which keeps track of how safe plant and animal species are.