Rubiales is a historical order of flowering plants (angiosperms) that was recognized in the Cronquist system of classification (published in 1981). In this system, Rubiales comprised a single family, Rubiaceae, which includes approximately 13,000 species such as coffee (Coffea spp.), quinine (Cinchona spp.), and gardenia (Gardenia spp.). The order was placed within the subclass Magnoliidae (dicotyledons).
Taxonomic characteristics
- Morphology: Members of Rubiaceae, and thus Rubiales, are typically shrubs, trees, lianas, or herbaceous plants. Common traits include opposite or whorled leaves with interpetiolar stipules, and tubular or funnel-shaped flowers often arranged in cymes or panicles. The fruit types vary widely, ranging from capsules and berries to drupes.
- Distribution: The former Rubiales had a cosmopolitan distribution, with a concentration of diversity in tropical and subtropical regions, especially in the Americas, Africa, and Southeast Asia.
Historical context and current usage
Rubiales was widely used in botanical literature throughout the latter half of the 20th century. However, subsequent phylogenetic studies based on molecular data led to a re‑evaluation of plant relationships. The Angiosperm Phylogeny Group (APG) system, first published in 1998, no longer recognizes Rubiales as a distinct order. Instead, the family Rubiaceae is placed within the order Gentianales (or occasionally within a broader clade of asterids depending on the APG version). Consequently, the term Rubiales is now considered obsolete in contemporary classification schemes, though it may still appear in historical references and some regional floras.
Etymology
The name Rubiales derives from the family name Rubiaceae, which in turn originates from the genus Rubia, a group of plants historically used for red dye production. The suffix “‑ales” is the standard botanical ending denoting an order.
References in literature
- Cronquist, A. (1981). An Integrated System of Classification of Flowering Plants. Columbia University Press.
- APG IV (2016). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants.
Note: While Rubiales is no longer an accepted order in modern taxonomic frameworks, the term remains part of the historical nomenclature of plant systematics.