acumen

1. (botany) A sharp, tapering point extending from a plant.Examples: "The black star of the corolla, characteristic of the original form, the manyfloweredness of the inflorescence (often connected with [3]—4 whirls), upper leaves in the inflorescence, adpression of the acumina of the calyx, its size, the closely situated anthers, long pistils, the length of the pedicel above and below the articulation and the thickness of the pedicel dominate."; "11. S. boyacense. Resembles S. Rybinii from which it is distinguished by the greater dissection of the leaves, the longer calyx acumens, smaller anthers and coloured corolla."; "Finally, the acumina of all the narrowly lanceolate leaves of both species tend to be straight rather than curved."uncountableusually

2. (anatomy) A bony, often sharp, protuberance, especially that of the ischium.Examples: "The rostrum is the anterior extension of the carapace between the eyes. It ends in a more or less acute tip, or acumen, and may have a lateral spine on each side or bear a longitudinal keel (carina) on the dorsal surface."; "DIAGNOSIS—Rostrum usually with marginal spines, tubercles, or angles at base of acumen, and rarely with low medina carina."; "Variations.—Most specimens examined have concave rostral margins that taper to the acumen and the rostral length is greater than the rostral width."uncountableusually