Dwarf shell orchid facts for kids

The dwarf shell orchid, also known as Pterostylis brevichila, is a special type of orchid. It grows only in the south-west part of Western Australia. This means it is "endemic" to that area.

Like other similar orchids called "greenhoods," these plants look different depending on if they are flowering or not. Plants that are not flowering have a flat circle of leaves, called a "rosette," on the ground. But when they are ready to flower, they grow a single flower on a tall stem with leaves on it. The dwarf shell orchid has a small white flower with brown stripes. It looks a bit like another orchid, P. aspera, but it is smaller.

What Does It Look Like?

The dwarf shell orchid is a plant that lives on land, not in water. It is a "perennial" plant, which means it lives for more than two years. It is also "deciduous," so some parts die back each year. This plant is a "herb," meaning it has soft stems, not woody ones like a tree. It grows from an underground "tuber," which is like a small potato.

When the plant is not flowering, it has a "rosette" of small leaves. This is a circular pattern of leaves that lie flat on the ground. You can often find many groups of these leaf rosettes without any flowers.

When it flowers, a single white flower with brown stripes appears. This flower is about 23–26 mm (0.9–1 in) long and 8–10 mm (0.3–0.4 in) wide. It grows on a stem that is about 60–120 mm (2–5 in) tall. This stem also has four or five leaves on it. These stem leaves are about 10–25 mm (0.4–1 in) long and 4–5 mm (0.16–0.20 in) wide.

The top part of the flower, called the "dorsal sepal," and the "petals" are joined together. They form a hood, which is called a "galea." This hood covers the central part of the flower, known as the "column." The dorsal sepal has a short, pointy tip. There is a small space between this hood and the "lateral sepals," which are the side parts of the flower. These lateral sepals have thin, thread-like tips that stand up straight. These tips are about 13–16 mm (0.5–0.6 in) long.

The "labellum" is the orchid's lip, and it is very short and straight on this plant. You cannot see it from outside the flower. These orchids usually flower between July and September.

How It Got Its Name

The dwarf shell orchid was officially named Pterostylis brevichila in 2012. It was described by two botanists, David Jones and Christopher French. They found a sample of the plant near a place called Scaddan. Their description was then published in a magazine called Australian Orchid Review.

Before it got its official name, people knew this plant as Pterostylis sp. 'dwarf shell'. The second part of its scientific name, brevichila, tells us something about the plant. It comes from two old words:

• brevis is a Latin word meaning "short."
• cheilos is an Ancient Greek word meaning "lip."

So, brevichila means "short lip," which refers to the orchid's short labellum.

Where Does It Live?

The dwarf shell orchid grows in a type of forest called "mallee woodland." It often likes to grow in thick groups of melaleuca plants. You can find this orchid in Western Australia. It grows in an area stretching from Hyden all the way to Mount Arid, which is in the Cape Arid National Park.

This area covers three special natural regions. These are the Coolgardie, Esperance Plains, and Mallee "biogeographic regions." These regions are defined by their unique plants, animals, and environments.

Protecting This Orchid

The Government of Western Australia's Department of Parks and Wildlife keeps track of plants and animals. They have listed Pterostylis brevichila as "not threatened." This means that, for now, there are enough of these orchids, and they are not in danger of disappearing.