Commelinaceae

Some plants have very special flowers.

They are called dayflowers. These flowers only stay open for one day. They do not make sweet nectar. Instead, they give pollen to bugs.

These plants have green stems. The leaves wrap around the stem. New leaves roll up like tubes. This helps them grow. Many of these plants live in warm lands. They can grow in a garden. They are very pretty to see.

Commelinaceae is a big family of flowering plants.

People call them dayflowers or spiderworts. There are about 731 known species. Many of these plants live in warm, tropical lands. Some grow in gardens as pretty plants.

These plants have many special parts. Their leaves wrap around the stem. This is called a leaf sheath. When new leaves grow, they roll inward. This way of unfurling is called involute. Most of these plants are perennials. This means they live for many years. Their flowers are often short-lived. They may only last for one day. These flowers do not have nectar. Instead, they give pollen to insects. Some flowers even trick bugs. They use yellow hairs to look like extra pollen. Most flowers are hermaphroditic. This means they have both male and female parts. Some plants have both male and bisexual flowers. The flowers grow in clusters. These clusters look like a scorpion's tail. This shape is called a thyrse.

Commelinaceae is a huge family of flowering plants. People often call them the dayflower or spiderwort family. This group is very large. It contains about 731 known species. These species belong to 41 different genera. Many of these plants are herbaceous. This means they are soft-stemmed plants. Some people grow them in gardens as ornamentals.

They grow in many warm places. You can find them in the Old World tropics. You can also find them in the New World tropics. Some types live in both areas.

These plants have a very interesting way of growing. Their leaves form a sheath at the base. This sheath wraps around the stem. It is a bit like the leaves on grass. Most leaves are simple and do not have teeth. They are often succulent, which means they are fleshy. When a new leaf grows, it unfurls in a special way. This is called involute. The edges of the leaf roll inward as they emerge.

Some plants in this family are even climbers. Genera like Streptolirion and Aetheolirion can climb upward.

The flowers in this family are quite unusual. Many flowers are ephemeral. This means they are very short-lived. They might only last for a single day. Some flowers even open at specific times of day. This helps keep different species separate. Most flowers do not have nectar. Instead, they offer pollen to pollinators. Some flowers even try to trick insects. They use yellow hairs to look like extra pollen. They may also use staminodes. These are parts that look like pollen-making stamens but do not make any.

Scientists use special systems to group these plants. The APG III system from 2009 recognizes this family. It places them in the order Commelinales. They belong to a group called the commelinids. Most species are perennials. This means they live for more than two years. However, a few species are annuals. Most grow in the ground. They are terrestrial plants. But the genus Cochliostema is different. These plants are epiphytes. This means they grow on other plants.

Flower shapes can change a lot in this family. Some flowers are zygomorphic. This means they have one plane of symmetry. Others are actinomorphic. This means they are shaped like a star. The flowers often grow in clusters called a thyrse. These clusters look like a scorpion's tail. Each small part is called a cincinnus. Flowers usually have three sepals and three petals. Most plants have six stamens. These stamens can be arranged in many different ways. This variety makes the family very special to study.

Commelinaceae is a large and diverse family of flowering plants. It is often called the dayflower or spiderwort family. This group is one of five families within the order Commelinales. It is the largest family in that order. Currently, scientists have identified about 731 known species. These species are organized into 41 different genera. Many of these plants are herbaceous, meaning they have soft stems. Because they are often colorful, people cultivate many species as ornamentals.

The plants in this family show incredible variation in their physical forms. This variation in morphology is exceptionally high among all flowering plants. Most members are terrestrial, meaning they grow in the ground. However, the genus Cochliostema contains epiphytes, which are plants that grow on other plants. Most species are perennials that live for several years. A smaller number of species are annuals that complete their life cycle in one year. Some genera, such as Streptolirion and Aetheolirion, are even climbers.

One way to identify these plants is by looking at their leaves and stems. The leaves are arranged alternately along the stem. They may be arranged in a spiral or in two rows. The leaf blades are simple and entire, so they lack teeth or lobes. Many leaves are succulent, which means they are fleshy. A distinctive feature is how the leaves unfurl from a bud. This process is called involute, where the leaf margins roll inward as they emerge.

The leaves also form a closed sheath at the base that surrounds the stem. This is similar to grass, but these sheaths do not have a ligule.

The flowers of Commelinaceae are famous for being ephemeral. This means they are very short-lived, often lasting only a day or even just a few hours. After they open, the flowers may deliquesce, or melt away. Because they are so short-lived, many species have specific flowering seasons. They may also flower at specific times of the day. This timing helps to isolate different species reproductively.

Interestingly, these flowers do not produce any nectar. Instead, they offer only pollen as a reward to pollinators. Some species even use deception to attract insects. They may use yellow hairs or broad anther connectives to mimic extra pollen. They might also use staminodes, which are sterile stamens that look like they contain pollen.

Flower structure in this family can be quite complex. The flowers can be actinomorphic, meaning they have radial symmetry like a star. They can also be zygomorphic, meaning they have only one plane of symmetry. Most species are hermaphroditic, containing both male and female organs. Some are andromonoecious, meaning they have both bisexual and male flowers on one plant. The single species Callisia repens is gynomonoecious, having both bisexual and female flowers. Other species are polygamomonoecious, possessing bisexual, male, and female flowers.

Each flower typically has three sepals and three petals. The petals are sometimes clawed, which means they narrow into a stalk at the base. There are almost always six stamens arranged in two whorls. These stamens show many different arrangements. In many genera, two to four of these are staminodes that do not produce pollen. The flowers often grow in an inflorescence called a thyrse. This structure is made of subunits called cincinni. These look like clusters shaped like a scorpion's tail along a central axis.

Taxonomists have long recognized this family. The APG III system, established in 2009, continues to recognize Commelinaceae. It places the family in the order Commelinales within the clade commelinids. Scientific analysis, such as the study by Burns et al. in 2011, shows that this is a monophyletic group. This means all members of the family share a single common ancestor. By studying DNA sequences from the plastid gene rbcL, researchers can map the evolutionary tree of these diverse plants.