Pterostylis cardiostigma facts for kids

The Pterostylis cardiostigma is a special kind of orchid that grows only in New Zealand. It has tall, upright leaves, with the top leaves growing even taller than its flower. The flower itself is stiff, stands straight up, and is mostly green with thin white stripes and pink tips. It often looks like it hasn't fully opened. Sometimes, people confuse it with a similar plant, Pterostylis banksii, which often grows nearby.

What Does Pterostylis cardiostigma Look Like?

Pterostylis cardiostigma is a plant that grows from the ground, not on other plants. It is a perennial plant, meaning it lives for more than two years. It's also deciduous, so its leaves fall off at certain times of the year. This plant has a large, heart-shaped part underground called a tuber, which stores food.

The flowering stem has about four to seven upright leaves. The very top leaf grows higher than the flower itself. These leaves are long and narrow, shaped like a spear, and can be about 8 to 28 centimeters (3 to 11 inches) long. They are also about 1 to 2 centimeters (0.4 to 0.8 inches) wide and have a noticeable red line down the middle.

The flower is green with thin white stripes and has pink or red tips. It grows on a stem that can be 6 to 35 centimeters (2 to 14 inches) tall. The top part of the flower, called the dorsal sepal, and the petals are joined together. They form a narrow hood, or "galea," over the central part of the flower called the column. The dorsal sepal is a bit longer than the petals. The lower part of this hood stands straight up, and the upper part curves forward.

The side sepals stand mostly upright and are much taller than the hood. They have long, thin, red, thread-like tips. The labellum (which is like the orchid's "lip") is curved, red, and pointed. If you were to carefully open the flower, you would see that the stigma (the part that receives pollen) has a unique heart shape. This orchid usually blooms from October to December.

How Pterostylis cardiostigma Got Its Name

The Pterostylis cardiostigma was officially named in 1983 by a scientist named Dorothy Cooper. She wrote about it in a science magazine called New Zealand Journal of Botany, based on a plant she found at Days Bay.

The second part of its name, cardiostigma, comes from two old Ancient Greek words. Kardia means "heart," and stigma refers to the part of the flower that collects pollen. So, the name cardiostigma means "heart-shaped stigma," which describes the special heart shape of its stigma.

Where Pterostylis cardiostigma Lives

This greenhood orchid grows in bushes and forests on both the North and South Islands of New Zealand. It is often found growing alongside another similar orchid, P. banksii.

How Pterostylis cardiostigma Reproduces

The flowers of P. cardiostigma are very narrow and often look like they haven't fully opened. When the flower is still developing, its labellum (lip) sticks out a bit. This suggests that insects or other things can help with pollination, which is how plants make seeds.

However, the stigma of this orchid is larger than in other Pterostylis plants. Because of its size, the pollen packets, called pollinia, often fall directly onto the stigma. This means the plant can often pollinate itself, a process called self-pollination.