PlantaeDB Logo
Login Sign-up

Genus Cordylanthus in Family Orobanchaceae

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!

The genus Cordylanthus (family Orobanchaceae) comprises approximately 15 species of annual or perennial hemiparasitic herbs native to western North America, ranging from British Columbia through California and into Baja California and the Great Basin. These plants typically inhabit dry, open grasslands, chaparral, sagebrush steppe, and pine-oak woodlands from sea level to montane elevations. The type species is Cordylanthus ramosus Nutt. ex Benth.

Morphologically, Cordylanthus is distinguished by its small, often inconspicuous flowers arranged in spikes or racemes, with showy bracts that frequently conceal the actual flowers. The bilabiate corollas are white to yellow or pinkish, adapted for insect pollination. Characteristic features include opposite or alternate leaves that may be entire to deeply lobed, often with a scurfy or glandular indumentum. The genus exhibits complete reduction of the calyx and fusion of bracts into an inflated involucre surrounding each flower. The superior ovary is typically bilocular with axile placentation, developing into a small capsule containing numerous dust-like seeds with reticulate testa.

Species diversity centers in California, where several narrow endemics occur, particularly in the coastal ranges and Sierra Nevada. Other diversity hotspots include the Great Basin region and Pacific Northwest. Most species occupy well-drained soils in arid to semi-arid climates, with many showing habitat specificity to serpentine soils or specialized microhabitats.

Cordylanthus species are hemiparasites, obtaining water and minerals from host plant roots while maintaining photosynthetic capacity. Pollination is primarily entomophilous, though specific mechanisms remain poorly documented in most species. Chromosome numbers vary, with n=16 being reported for several species.

Taxonomically, Cordylanthus belongs to the hemiparasitic clade within Orobanchaceae, closely related to Orthocarpus and other pedalium members. Recent molecular phylogenetic work has confirmed its placement in subtribe Castillejinae (Tank & Olmstead, 2020). The genus has remained relatively stable despite ongoing phylogenetic investigations, though some species boundaries remain contested.

While not economically significant, several species appear in horticultural collections, particularly those with showy bracts. Cordylanthus tenuifolius and related taxa are occasionally cultivated in native plant gardens. No Cordylanthus species are considered invasive, though habitat loss from development threatens several California endemics.

Conservation concerns focus on habitat destruction and climate change impacts on narrow endemics. Current research gaps include detailed life history studies and comprehensive population assessments for rare species. POWO, 2024; WFO, 2024; Tank & Olmstead, 2020.

Pick a Species to see its components: