PlantaeDB Logo
Login Sign-up

Genus Delairea in Tribe Senecioneae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Delairea is a small genus in the Asteraceae (tribe Senecioneae), comprising about one species. The widely cultivated Cape ivy is treated as Delairea odorata, a scrambling, evergreen climber native to coastal southwestern South Africa, now naturalized in warm temperate and subtropical regions of several continents (POWO, 2024; WFO, 2024). Lemaire’s original description has Delairea odorata as the type.

The genus is recognized by a weakly woody, rooting, climbing habit with distinct tendril-like leafless branches; leaves are aromatic, broad and shallowly lobed to palmately divided, with cuneate bases and an entire to weakly crenate margin; capitula are in lax, terminal panicles, each with pale yellow or cream rays and yellow discs; cypselas bear pappus of fine hairs (Geyser & Norlindh, 1963; Jeffrey, 1986). Compared with Senecio, the genus shares the dioecious-weedy syndrome but differs in the climbing habit, deeply lobed leaves, and the distinctive late-season panicle.

The center of diversity is in the Cape Floristic Region, particularly the fynbos; the species occupies forest margins, roadsides, and coastal sites, often naturalized in disturbed habitats at low to mid elevations. It is also widespread in California, parts of Europe, Australia, New Zealand, and elsewhere as an environmental weed (GBIF, 2024).

pollination and dispersal are little studied, but capitula suggest generalist insects; the pappus indicates wind-assisted seed dispersal. Life-history data are limited to field observations. The base chromosome number has been reported as x=10 (Raven et al., 1960; cited in Raven & Kyhos, 1961), but this number is not widely re-examined and remains provisional pending targeted karyological work.

Species delimitation is stable; no subgenera or sections are used. Recent phylogenies consistently place Delairea within a derived clade of Senecio, often near Senecio linearifolius and allied taxa, prompting proposals to merge it into Senecio. Pelser et al. (2007) and Nordenstam (2007) recommended this transfer, and selective analyses by Barker et al. (2016) supported the placement. Many checklists maintain Delairea as a separate genus for practical reasons (POWO, 2024; WFO, 2024).

In horticulture, Delairea odorata is valued as a fragrant, fast-growing evergreen climber; it is also a notorious invader in disturbed sites and coastal communities, where it forms dense mats that displace native flora and impede regeneration (Cal-IPC, 2006). No significant timber or agricultural use is documented.

Conservation concerns are minor for the native range, but naturalized populations warrant risk management. With ongoing sequencing clarifying its position in Senecio, formal taxonomic revisions and targeted ecology studies are expected to sharpen both phylogenetic and management frameworks.

Pick a Species to see its components: