Rhinanthus minor L.

Abstract

Scrophulariaceae, Pedicularieae. Yellow-rattle. Rhinanthus minor L. sensu lato is a summer annual, facultative hemiparasitic therophyte. Stem erect, simple or branched and up to 500 mm, 4-angled and often streaked or spotted black. Leaves 20–30 mm × (2–)5–8 mm, opposite, sessile, subcordate at base, ovate to lanceolate and entire to dentate, scabrid at least above, hairy or not. Flowers solitary, subsessile, in axils of leaf-like bracts in terminal spike-like racemes. Bracts triangular, glabrous or somewhat scabrid, longer to slightly shorter than calyx; lower teeth of bracts not much longer than the upper. Intercalary leaves (at nodes on the main stem between the highest branches and the lowest bract) 0–6 pairs. Calyx 4-toothed and flattened, usually mid-green or with a reddish-tinge, hairy only on the margins, or all over. Corolla 12–15(–17) mm, yellow to brownish-yellow; mouth of corolla somewhat open. Lower lip 3-lobed, turned down away from upper lip. Upper lip compressed, with two violet teeth (rounded) below the apex, < 1 mm, shorter than wide. Dorsal line of corolla ± straight proximally, merging into convexly curved upper lip. Didynamous; stamens included in upper lip of corolla. Stigma included or slightly exserted. Anther-lobes hairy, not mucronate. Seed capsules shorter than calyx, compressed and loculicidal, seeds few. Seeds ± discoid, always winged, without oil-body. Seeds 4.9 × 3.8 mm; mean seed mass 2.84 mg (Grime et al. 1988).