Ourisia calycina Colenso

About Ourisia calycina Colenso

Ourisia calycina Colenso is a species of large perennial herb. It has creeping horizontal stems, with opposite leaves that grow in tight tufts along the stem. Leaf petioles range from 7.2 to 109.6 mm in length. Leaf blades measure 12.3–135.1 mm long by 7.4–71.4 mm wide, giving a length-to-width ratio of 1.0–1.7:1; blade shape ranges from narrowly to very broadly ovate, widest below the middle, with an acute apex, a cuneate or truncate base, and regularly crenate edges. Leaves are mostly glabrous (hairless), except for a fringe of dense, long non-glandular hairs along the lower edges. The lower leaf surface is densely punctate, and also bears non-glandular hairs on the midvein. Inflorescences are erect racemes that can grow up to 61 cm long. The peduncle has lines of non-glandular hairs; each raceme has 1 to 8 flowering nodes and can hold up to 32 or more total flowers. Each flowering node holds up to 9 flowers and 3 to 9 sessile, clasping bracts, which are usually lanceolate to narrowly ovate, or oblanceolate to obovate. The lowest bracts are similar in size to the plant’s leaves, measuring 20.4–76.1 mm long and 6.2–36.3 mm wide, and bracts get smaller moving toward the apex of the raceme. Flowers grow on pedicels up to 64.7 mm long; pedicels are either glabrous or hairy, and only bear non-glandular hairs. The calyx is 7.5–12.2 mm long, regular, with all lobes divided equally all the way to the base. Calyx lobes are acute, with smooth or irregularly notched edges, and have a few to densely distributed non-glandular hairs along the edges and base. The corolla is 16.4–31.3 mm long including a 5.7–16.1 mm long corolla tube, bilabiate, and tubular-funnelform. The outside of the corolla is glabrous and white, sometimes flushed pink; the inside is yellow and has three lines of yellow hairs. Corolla lobes are 5.9–15.3 mm long, spreading, and shaped obovate or obcordate. There are 4 didynamous stamens up to 15.9 mm long; two longer stamens are exserted, while two shorter stamens reach only to the opening of the corolla tube. A short staminode 0.5–4.1 mm long is also present. The style is 5.5–10.7 mm long, and is either exserted or reaches the corolla tube opening, with an emarginate stigma. The ovary is 3.0–4.6 mm long and glabrous. Fruits are capsules 5.0–9.9 mm long and 4.0–8.0 mm wide that undergo loculicidal dehiscence; fruiting pedicels can grow up to 80.5 mm long. Each capsule holds approximately 630 seeds. Seeds are 0.4–1.3 mm long and 0.1–0.8 mm wide, with a two-layered, reticulate seed coat. Ourisia calycina flowers from October to March and fruits from December to March. Its diploid chromosome number is 2n=48. This species is endemic to the northern and central South Island of New Zealand, occurring most often in Canterbury and Westland; two specimens have also been recorded from northern Fiordland. It grows in herbfields, scrub, meadows, and grasslands within damp, sheltered, rocky or open montane to subalpine habitats, at elevations from 540 to 2,000 m (1,770 to 6,560 ft) above sea level.