Amaranthaceae

Many plants belong to one big family.

Some plants are small herbs. Others grow as big shrubs or trees. Many of these plants live in very dry lands. They can even grow in salty soil.

Some plants in this group help us. We eat spinach and beets as food. We also eat seeds like quinoa.

Other plants are used for medicine. Some are even used to make soda ash. Some plants in this group are just weeds.

These plants grow all over the world. They live in warm and cool places.

The Amaranthaceae family is a very large group of plants.

This group has about 2,040 different species. Most are small herbs. Some grow as shrubs. Very few grow as trees or vines. Some plants in this group have thick, fleshy parts. These are called succulents.

Many of these plants live in dry places. Some can even grow in salty soil. We call these plants halophytes. This helps them live where other plants might die. Many species use a special way to make food. This is called C4 photosynthesis. It helps them use water well. This was a way to survive heat and dry air.

People use many plants in this family. We eat spinach and beets as vegetables. We also eat seeds like quinoa and kañiwa. These seeds are used like grains. Some plants are used for medicine. Other plants are used in gardens because they look pretty. However, some are just weeds. Some can even cause allergies from their pollen.

Caption: A map of how these plants are related.

The Amaranthaceae family is a huge group of flowering plants.

It includes about 165 different genera and 2,040 different species. This makes it the largest group within its larger order, Caryophyllales. Most of these plants are small herbs or subshrubs. Some grow as larger shrubs, but very few are trees or vines. Some species are even succulents, which means they have fleshy parts to hold water. Many of these plants have stems with thickened nodes.

These plants have many different ways to grow and survive. Most have simple leaves that are mostly alternate on the stem. Some species even have leaves that are tiny scales. Their flowers can be alone or grow in groups called cymes, spikes, or panicles. These flowers are often perfect, which means they have both male and female parts. The seeds or fruits are often protected by the flower parts. This helps the plant spread its seeds to new places.

Scientists have studied this family for a long time. Antoine Laurent de Jussieu first published the name Amaranthaceae in 1789. He wrote about it in a book called Genera Plantarum. Later, Étienne Pierre Ventenat published the name Chenopodiaceae in 1799. For a long time, these were seen as two different families. Now, scientists use a system called APG IV from 2016. This system places them together in one big family.

There are many interesting facts about how these plants live. About 800 species use a special way to make food called C4 photosynthesis. This pathway helps them use water more efficiently. This was a way to survive as the air became drier and temperatures rose. This special way of making food first appeared around 24 million years ago. Some groups developed it much later, about 6 million years ago or even less.

Humans use many members of this family every day. We eat spinach and beets, like beetroot and chard, as vegetables. We also eat seeds from Amaranthus, quinoa, and kañiwa as pseudocereals. Some plants, like epazote, are used as medicinal herbs. Other plants are grown in gardens because they are pretty. However, some species like redroot pigweed are considered weeds. Some plants in this family can even cause pollen allergies.

The Amaranthaceae family is a massive group of flowering plants. It is the most species-rich lineage within its parent order, Caryophyllales. This family includes about 165 different genera and 2,040 species. Many people know these plants through the type genus, Amaranthus. The family is also unique because it absorbed the former goosefoot family, known as Chenopodiaceae.

Most species in this family are annual or perennial herbs. Some are subshrubs, while others grow as larger shrubs. Very few species in the family function as vines or trees. Some plants are even succulents, meaning they have fleshy parts to store water. Many species feature stems with thickened nodes. A curious trait in many species is anomalous secondary growth in the perennial stems. Only the subfamily Polycnemoideae exhibits normal secondary growth. The leaves are mostly simple and alternate, though some are opposite. They never possess stipules. Leaf shapes vary greatly from flat to terete, which means cylindrical. Some species even have leaves reduced to tiny scales.

The flowers of Amaranthaceae are highly diverse. They can appear as solitary flowers or in groups called cymes, spikes, or panicles. Most flowers are perfect, meaning they are bisexual and contain both male and female parts. However, some species have unisexual flowers. The flowers typically have a perianth made of one to five tepals, which are often joined. In rare cases, they may have up to eight tepals. The stamens are usually one to five in number. These stamens are either opposite the tepals or alternate. The anthers, which hold the pollen, contain two or four pollen sacs called locules. In the tribe Carboxyloneae, the anthers have special vesicular appendages. The pollen grains are spherical and pantoporate, meaning they have many pores. Some species, like Froelichia, can have up to 250 pores per grain.

Survival in harsh environments is a key feature of this family. About 800 species utilize C4 photosynthesis. This is a specialized metabolic pathway that allows plants to make food more efficiently. In the Amaranthaceae, this pathway is the largest group among the eudicots. Scientists believe this pathway evolved about 15 times independently within the family. The first instances appeared during the early Miocene, roughly 24 million years ago. Other groups evolved it much later, perhaps only 6 million years ago. This evolution was likely a response to decreasing atmospheric levels and increasing temperatures. It also helped plants survive permanent shortages in water supply. By using water more efficiently, these plants gained a selective advantage in arid habitats.

The history of naming this family involves several important scientists. Antoine Laurent de Jussieu first published the name Amaranthaceae in 1789. He included it in his work, Genera Plantarum. Later, Étienne Pierre Ventenat published the name Chenopodiaceae in 1799. For a long time, these were treated as separate families. However, modern phylogenetic research has changed how we classify them. The APG IV system of 2016 now places them together in one large family. This broad definition is known as Amaranthaceae sensu lato. Research shows that the older name, Amaranthaceae, has priority and remains the valid scientific name.

Humans interact with Amaranthaceae in many practical ways. We consume many species as vital food sources. Spinach and various forms of beet, such as beetroot and chard, are common vegetables. We also eat seeds from Amaranthus, quinoa, and kañiwa. These are often called pseudocereals. Some plants, like Dysphania ambrosioides, are used as medicinal herbs. Other species, such as those in the genus Salicornia, are used to produce soda ash. In gardens, plants like Celosia and Iresine are popular ornamentals. However, some species can be problematic. Redroot pigweed and alligatorweed are often considered weeds. Some members of the family can also trigger pollen allergies.

Taxonomy, or the science of classification, is still evolving for this group. Molecular genetic studies have shown that old methods based on physical shapes were sometimes incorrect. Current research is dividing the former Chenopodiaceae into eight distinct subfamilies. These include Polycnemoideae, Betoideae, Camphorosmoideae, Chenopodioideae, Corispermoideae, Salicornioideae, Salsoloideae, and Suaedoideae. When looking at the entire broad family, there are approximately 10 subfamilies. These subfamilies contain about 180 genera and roughly 2,500 species. This complex system helps scientists understand the deep evolutionary history of these diverse plants.