RUBIACEAE

by Sarah Noller

Family Description:

            This family is also known as the coffee, madder and bedstraw family.  It is one of the largest plant families consisting of about 620 Genera and 10,700 species that are mostly perennial trees, shrubs, vines and infrequently herbs.  There are three subfamilies; Rubioideae that are commonly herbs, Cinchonoideae, and Ixoroideae that contains coffee and gardenias.

            Floral traits: Flowers are bisexual, actinomorphic and heterostylous with cymose inflorescences.  The stigmas are usually bilobed except for Gardenias.  The petals are fused (sympetalous corolla) with 4-5 lobes.  The androecium has the same number of stamens as corolla lobes and is attached to corolla tube or epigynous zone, near summit of ovary, and alternates with lobes.  The gynoecium consists of a single compound carpel, a single style and nearly always inferior ovary.  The number of ovary cavities, or ocules, equals the number of carpels each with 1 to many axile ovules.  An epigynous nectary disk is usually present.

                Fruits: Fruit fleshy, or non-fleshy; dehiscent, or indehiscent, or a schizocarp.  They are drupaceous or capsular with seeds of 1 to many.

 Coprosma longifolia, pilo, hupilo, O'ahu, Hawaii, endemic.
 http://www.botany.hawaii.edu/faculty/carr/rubi.htm     

Leaves: They are simple, entire and opposite.  The leaves of some species, such as Galium, can sometimes appear whorled due to having stipules as large as regular leaves that are interpetiolar.

Stem anatomy: Plants are predominantly woody.  Young stems are tetragonal.  Cork cambium is usually present or absent as in Galieae.

 Worldwide Distribution:

            Members of this family can be found just about all over.  In temperate regions, Rubiaceae are represented by a few herbaceous genera, e.g. Galium.  They are also a major component of all tropical woody vegetation, especially the rain forest understory.  Coffee is native to eastern Africa and Southern Asia.  The Cinchona tree is native to South America.

 Habitats:

            This family can be found in a wide variety of habitats, from frigid zones to tropical shady areas, woodland areas, volcanic terrains, lava strewn coasts, pastures and dry prairie hillsides.  Most generally need lots of moisture.  Coffea arabica needs 75 or more inches of rain a year.

Economic Importance:

            The most popular genera of economic importance are coffee (Coffea).  It is second only to petroleum in terms of value in international markets.  There are three species used for coffee; C. arabica which comprises 90% of all coffee, C. canephora 9% and C. liberica 1%.  Coffee is native to Ethiopia and spread to Egypt by 1510 and reached England and Europe by the 1600’s.  The Arabs monopolized the market for years.  In the 1720’s, coffee was transported to the Caribbean after being stolen from the Paris Botanical Gardens then transported to Brazil, which is now the top grower of coffee worldwide.

            The Cinchona tree produces quinine, an anti-malarial compound, which is an alkaloid.  It is native to South America but is also cultivated in other tropical regions such as India and Java.  The bark is the medicinally important part.  As a medicinal herb, it is known as Peruvian Bark.  It is stripped from the tree then dried and powdered but rarely used today because it can be dangerous in large doses.  Linnaeus named it after a countess of Chinchon, the wife of a viceroy of Peru, who in 1638 was introduced by natives to the medicinal properties of the bark when, according to legend, saved his wife form malaria.

                Another economic use is ipecac.  It comes from dried rhizomes and roots of Cephaelis acuminate and Cephaelis ipecacuanha.  It has been used since ancient times especially as a source of a drug to treat poisoning by inducing nausea and vomiting.

            The red dye, alizarin, comes from the roots of Rubia tinctorum and Rubia cordifolia.

            There are many ornamentals sold in this family including, Gardenia, Rubia, Mitchella and Coprosma.

 
 Weeds:

            Galium, also known as bedstraw, is considered a weed.  There is also one species, Spermacoce alata, or winged false buttonweed, which is listed as a USA Federal Noxious Weed.

Phylogenetic position:

Kingdom: Plantae
    Phylum: Magnoliophyta
       Class: Magnoliopsida
          Order: Gentianales
                Family: Rubiaceae

Local Kansas Representatives:

            There are four species that appear here; Diodia teres or buttonweed, Galium or bedstraw, Hedyotis crassifolia with single bluish flowers, and Hedyotis nigricans with clusters of white flowers.