PlantaeDB Logo
Login Sign-up

Genus Hemarthria 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!

Hemarthria R.Br. is a genus of perennial grasses in Poaceae (subfamily Panicoideae, tribe Andropogoneae), often placed near Rottboellia L.f. in subtribe Andropogoninae. It includes roughly a handful of accepted species that are widespread across tropical and subtropical Africa and Asia and extend into northern Australia, commonly along waterways, marshes, floodplains, and wetter savannas and grasslands; one species, Hemarthria compressa, is often treated as the type (see Clayton & Renvoize, 1986; Govaerts, 1999). The genus is distinguished by rhizomatous or stoloniferous, usually caespitose perennials with flattened to compressed culms; blades that are linear to lanceolate and often glaucous; and characteristically laterally compressed, often slightly falcate inflorescence racemes that appear solitary and subterminal on the culm. The racemes are unbranched, the spikelets paired (sessile/pedicellate) and almost always sunken into a thickened, shallowly concave rachis. Sessile spikelets are typically awnless or only weakly awned; the callus is short, and the lower glume is coriaceous and convex; pedicellate spikelets are usually similar to or smaller than the sessile florets. The fruit is a caryopsis with superior embryo and linear hilum.

Centers of diversity lie in tropical Asia and Africa, with regional endemics in southern Asia and Australia (Govaerts, 1999; Clayton et al., 2002). Species usually occur in lowland to mid‑elevation, seasonally water‑logged or open habitats, including marshes, riverbanks, and seasonally flooded grasslands, where they form low, spreading swards. Intrinsic biology is typical of Andropogoneae: wind pollination, and dispersal by water or animal movement of the compact, laterally compressed racemes that persist on the parent plant. Chromosome counts of n = 9 and 2n = 18 are well established in H. compressa, consistent with the base number x = 9 for many members of the tribe (Ghosh & Singh, 1981).

Taxonomically, Hemarthria has been treated as a small, well‑circumscribed genus (Clayton & Renvoize, 1986; Govaerts, 1999), yet modern phylogenetic work in the tribe sometimes resolves Hemarthria as nested within Rottboellia and has prompted suggestions to lump the two (Duvall & Mort, 2005; Teerawatananon et al., 2011). The accepted list at Kew (POWO, 2024) and World Flora Online (WFO, 2024) continues to recognize Hemarthria alongside Rottboellia, so both treatments remain viable. Minor taxonomic adjustments have been made to species limits over the last two decades, with most synonyms applying to broad‑leaved Asian taxa formerly treated as Rottboellia sect. Hemarthria (Govaerts, 1999; WFO, 2024).

In human relevance, H. compressa is a valued pasture and fodder grass in wetter tropical pastures and on the fringes of paddy fields, prized for its productivity on seasonally water‑logged soils; H. altissima is likewise cultivated and occasionally naturalized in disturbed, moist sites (Clayton & Renvoize, 1986; FAO, 2024). The status of Hemarthria as threatened is under‑documented; most species are widespread and weedy, and conservation priorities remain unclear, with integrated phylogenetic work and regional floras needed to resolve the Hemarthria–Rottboellia boundary (POWO, 2024; WFO, 2024).

Pick a Species to see its components: