Galium

Flowers February 2008-4

Galium is a large genus of herbaceous plants in the Rubiaceae family, commonly known as bedstraw. There are around 650 species globally, distributed in a variety of habitats from lowland areas to mountains. Galium species are characterized by their whorled leaves, small, star-shaped flowers, and square stems. Many species are used in traditional medicine, and some, like Galium verum (yellow bedstraw), have been used in cheese making and as a dye.

Description

Galium species are mostly perennial, with a few annuals. They have slender, often climbing or sprawling stems. The leaves are simple, lanceolate to ovate, and arranged in whorls of 4 to 8 around the stem. The flowers are small, with four petals, and can be white, yellow, or pink. They are produced in cymes or panicles. The fruit is a dry schizocarp, splitting into two mericarps when mature.

Ecology

Galium species play a significant role in their ecosystems. They are pollinated by a variety of insects, including bees and flies. Some species, such as Galium aparine (cleavers), have a sticky surface that allows them to attach to animals and humans for seed dispersal. They are also host plants for several butterfly and moth species.

Uses

Historically, Galium verum was used to coagulate milk in cheese making, a practice that gave it the common name "cheese rennet". The roots of some species, like Galium odoratum (sweet woodruff), contain coumarin and are used to flavor beverages and as a fragrance. Galium aparine has been used in traditional medicine for its diuretic and lymphatic system cleansing properties.

Cultivation

Some Galium species are cultivated as ornamental plants in gardens. They are valued for their ability to cover ground quickly, their delicate flowers, and in some cases, for their aromatic foliage. They generally prefer well-drained soil and can tolerate a range of light conditions, from full sun to partial shade.

Species

Notable species within the genus include:

• Galium aparine (cleavers or goosegrass)
• Galium odoratum (sweet woodruff)
• Galium verum (yellow bedstraw)
• Galium mollugo (hedge bedstraw)

Conservation

While many Galium species are common and not considered at risk, some are rare and face threats from habitat loss, pollution, and climate change. Conservation efforts are important to preserve these species in their natural habitats.