PlantaeDB Logo
Login Sign-up

Genus Rydingia in Family Lamiaceae

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!

Rydingia Scheen & V.A.Albert (Lamiaceae, tribe Mentheae, subtribe Menthinae) is a small genus of aromatic dwarf shrubs and herbaceous perennials comprising approximately three species, R. caucasica, R. persica and R. rechingeri. Its centre of diversity lies in the Irano‑Turanian highlands of the eastern Caucasus and the Zagros Mountains, where plants occupy sub‑alpine meadows and rocky slopes between 1500 and 3000 m. The type species, R. caucasica (Scheen & Albert 2009), was originally described as a member of Satureja before molecular evidence justified generic separation.

Morphologically the genus resembles other Menthinae but is recognised by a combination of characters: quadrangular, often glabrescent stems; opposite, decussate leaves that are linear to narrowly lanceolate with revolute margins and usually lack dense glandular indumentum; inflorescences are verticillasters arranged in terminal spikes; flowers possess a tubular, five‑toothed calyx that is only mildly inflated and a bilabiate corolla (pink‑purple) with an included staminal column; the superior ovary is four‑lobed and each lobe bears a single basal ovule; the fruit splits into four smooth, glossy nutlets that have a small ventral areole. These features distinguish Rydingia from Satureja, which has longer calyx teeth and more densely glandular foliage, and from Thymus, which usually bears a markedly elongated calyx tube.

Molecular phylogenies place Rydingia as sister to a clade comprising Satureja s.str. and Thymus (Scheen & Albert 2009; Drew & Sytsma 2012). The monophyly of the genus is supported, and no sections are recognised. Historically all species were included in Satureja, but re‑circumscription based on both morphology and DNA data led to the erection of Rydingia (Scheen & Albert 2009). While some authors treat the name as a synonym of Satureja (Govaerts et al. 2015), POWO (2024) and WFO (2024) recognise Rydingia as an accepted genus.

Pollination is primarily by bees and other Hymenoptera, consistent with the typical Lamiaceae floral syndrome, and seed dispersal is passive, with nutlets falling near the parent plant or being transported short distances by small mammals. Base chromosome number is x = 15, with counts of 2n = 30 reported for R. caucasica (Scheen & Albert 2009). The plants are not widely cultivated but occasionally appear in rock‑garden collections for their compact habit and foliage; they are not known to be invasive.

Populations are fragmented and threatened by overgrazing and habitat degradation. Ongoing climate change may further contract high‑elevation habitats, making targeted monitoring and ex situ conservation essential for the long‑term persistence of the genus.

Pick a Species to see its components: