Isachne cuspidata (Poaceae): A New Species From the Western Ghats of Kerala, India

Isachne cuspidata, a new grass species from the Western Ghats of Kerala, is described here. Traits such as indumentum of the culms, leaves, and glumes; leaf shape; venation of the glumes and lemmas; and the shape and size of the glumes and lemmas have been used to distinguish species of Isachne . The new species belongs to sect. Isachne and is similar to I. kunthiana in having homomorphic florets and 7‐nerved glumes. I. cuspidata has also been compared to I. setosa , since they share a similar habit, especially in the panicle size, and both have 7‐nerved glumes. I. cuspidata differs from both I. kunthiana and I. setosa in having glabrous culm nodes, densely pubescent and lanceolate leaves, oblique and truncate leaf bases, up to 2 mm long spikelets having 1–2 mm long broadly elliptic glumes with cuspidate apices, florets with rachilla extension, and orbicular, 5‐nerved lemmas. Detailed morphological descriptions, field photographs, microscopic images, and an analysis of its taxonomic relationships with closely related species are provided.