PlantaeDB Logo
Login Sign-up

Genus Anthoxanthum in Family Poaceae

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 Anthoxanthum L. (family Poaceae, subfamily Pooideae, tribe Poeae, subtribe Alopecurinae) comprises approximately 30 species of perennial grasses distributed across temperate regions of the Northern Hemisphere and isolated tropical mountains. The type species is Anthoxanthum odoratum L., which is the standard for the genus (POWO, 2024; WFO, 2024).

Diagnostic morphology: Plants form dense tufts with erect culms and slender, flat leaf blades. A membranous ligule crowns the sheath; the leaf margins are smooth. The inflorescence is a compact, spike‑like panicle bearing numerous spikelets. Each spikelet contains a lower sterile lemma that bears a long, twisted awn and an upper fertile lemma that is also awned, giving the head a feathery appearance. The flower has two lodicules, a superior ovary with two free carpels and a single ovule per carpel, and the fruit is a small, laterally compressed caryopsis.

Diversity and range: Species richness peaks in the Mediterranean Basin, the Caucasus, the Himalayas, and western North America. Endemic taxa occur on calcareous rocky outcrops in the Alps and on high‑altitude grasslands of eastern Africa. Typical habitats include mesic to dry meadows, open woodlands, and alpine slopes from sea level to over 3000 m (WFO, 2024). The distribution pattern reflects post‑glacial migration and geographic isolation (Soreng et al., 2022).

Intrinsic biology: All members are wind‑pollinated (anemophilous) C₃ grasses. The base chromosome number is x = 7, with numerous polyploid cytotypes reported across the range (GPWG, 2023). Some populations exhibit facultative apomixis, as noted in the same phylogenomic work (GPWG, 2023), contributing to rapid colonization of disturbed sites.

Taxonomy and phylogeny: Modern molecular analyses place Anthoxanthum within subtribe Alopecurinae and sister to Hierochloe (GPWG, 2023; Soreng et al., 2022). Recent revisions have transferred several Hierochloe species to Anthoxanthum, as reflected in POWO (2024). An alternative treatment, advocated by Tsvelev (2012), retains a broader Hierochloe concept that includes the former Anthoxanthum species, highlighting unresolved generic boundaries.

Human relevance: A. odoratum* is valued for its fragrant foliage in traditional haymaking and as an ornamental aromatic grass. Other species are occasional weeds in pastures, especially where they establish dense stands after disturbance (WFO, 2024). The genus contributes little to timber or food crops but provides ecosystem services through soil stabilization.

Conservation and outlook: While most species are widespread and of low conservation concern, narrowly endemic taxa are vulnerable to habitat loss and climate change. Targeted taxonomic clarification and population monitoring remain priorities for future research.

Pick a Species to see its components: