Rosetted elbow orchid facts for kids

The Arthrochilus rosulatus, also known as the rosetted elbow orchid, is a special type of flowering plant. It belongs to the orchid family. This plant is found only in Tropical North Queensland, Australia. It has a group of bluish-green leaves shaped like a rosette at its base. The orchid can have up to fifteen pale green flowers that look like insects. These flowers have dark red glands on their labellum, which is a special lip-like part of the flower.

What Does the Rosetted Elbow Orchid Look Like?

The rosetted elbow orchid is a plant that grows from the ground. It is a perennial plant, meaning it lives for more than two years. It is also deciduous, so its leaves fall off at certain times. This plant has an underground tuber, which is like a storage organ. This tuber can grow new tubers on the ends of root-like stolons.

Around the bottom of its flowering stem, the orchid has a rosette of three to four leaves. These leaves are shaped like an ellipse or a spear. Each leaf is about 10–35 mm (0.4–1 in) long and 8–12 mm (0.3–0.5 in) wide.

The orchid's flowering stem grows to be about 70–150 mm (3–6 in) tall. It holds between two and fifteen pale green flowers. Each flower looks like an insect and is about 8–13 mm (0.3–0.5 in) long.

The top sepal (a leaf-like part that protects the flower bud) is thin and shaped like an egg. It is 7.5–9 mm (0.30–0.35 in) long and about 2 mm (0.08 in) wide. It partly wraps around the base of the column, which is the central part of the orchid flower. The side sepals are oblong or spear-shaped. They are 5.5–6.5 mm (0.2–0.3 in) long and about 2 mm (0.08 in) wide.

The petals are thin and straight, about 6.5–7.5 mm (0.26–0.30 in) long and 1 mm (0.04 in) wide. They are also curved. The side sepals and petals bend back against the ovary, which holds the seeds.

The labellum (the orchid's special lip) is light green with a dark purple spot at its base. It is about 5 mm (0.2 in) long and 1 mm (0.04 in) wide. It sits on a short stalk called a "claw." There is a part on the labellum called a callus that looks like an insect. It is about 3.5 mm (0.1 in) long and has short, reddish-brown, hair-like glands in the middle. The tip of the callus is about 1.5 mm (0.06 in) wide and has shiny dark red or black glands.

The column is clear with some purple spots and is curved. It has two pairs of curved wings. This orchid blooms from November to July.

How Did It Get Its Name?

The Arthrochilus rosulatus was officially named in 1991 by David Jones. He described it from a plant he found near Rossville. His description was published in a scientific journal called Australian Orchid Research.

The second part of its scientific name, rosulatus, comes from a Latin word. It means "of roses." This name refers to how the leaves form a rosette around the base of the flowering stem. This is different from other orchids in the same genus that have their rosettes on side growths.

Where Does This Orchid Live?

The rosetted elbow orchid grows in forests near Cooktown. Sometimes, many of these orchids grow together, forming large groups.

How Does It Reproduce?

Like other Arthrochilus orchids, the A. rosulatus orchid is pollinated by male thynnid wasps. These wasps belong to the genus Arthrothynnus. We don't know the exact species of wasp that pollinates this specific orchid yet.

This orchid can also make new plants without needing seeds. It does this by growing new tubers underground.