Ourisia macrophylla Hook.

Taxonomic Identity

Ourisia macrophylla Hook. is a large species of perennial herb. It has creeping horizontal stems, with opposite leaves that grow in tight tufts along the stem.

Leaf Petiole Size

Leaf petioles measure 4.3–225.0 mm in length.

Leaf Blade Dimensions

Leaf blades are 10.4–160.0 mm long by 5.9–99.0 mm wide, giving a length-to-width ratio of 0.9–2.3:1.

Leaf Blade Morphology

Blades are most often narrowly ovate to broadly ovate, widest below the middle, with an acute or rounded apex; a truncate, rounded, cuneate or cordate base; and crenate to crenate-serrate margins.

Leaf Surface Characteristics

Leaves may be glabrous, or have anywhere from few hairs to dense covering of non-glandular hairs on both surfaces, and the lower leaf surface is punctate.

Inflorescence Structure

Inflorescences are erect hairy racemes that reach up to 64.8 cm long, with 1–6 flowering nodes per raceme and up to a total of 53 flowers per raceme.

Flowering Node Bracts

Each flowering node holds up to 12 flowers and 2–12 sessile bracts that sometimes clasp the stem; these bracts are usually narrowly lanceolate to narrowly ovate. The lowest bracts are similar in size to the plant's leaves, measuring 10.4–78.9 mm long and 4.0–32.0 mm wide, and bracts get smaller toward the apex of the raceme.

Flower Pedicel Traits

Flowers are carried on a densely hairy pedicel up to 56.4 mm long; the pedicel has glandular hairs, and sometimes only non-glandular hairs in addition.

Calyx Morphology

The calyx is 3.6–10.0 mm long, regular, with all five lobes divided all the way to the base, and has isolated to sparsely distributed hairs, which are usually a mix of glandular and non-glandular types.

Corolla Structure and Size

The corolla is 10.3–22.2 mm long (including a 2.9–12.3 mm long corolla tube), bilabiate, and tubular-funnelform.

Corolla Color and Hairiness

It is usually hairy, white on the outside (sometimes flushed pink), and yellow on the inside, with three lines and a ring of yellow hairs inside.

Corolla Lobe Traits

Corolla lobes are 3.1–11.1 mm long, spreading, and shaped obcordate or obovate-spathulate.

Stamen Characteristics

There are 4 didynamous stamens up to 11.2 mm long: two long stamens that are exserted or reach the corolla tube, and two short stamens that also usually reach the opening of the corolla tube. A short staminode measuring 0.3–1.0 mm is also usually present.

Style and Stigma Traits

The style is 3.7–8.2 mm long, exserted, and has an emarginate stigma.

Ovary Traits

The ovary is 1.6–4.4 mm long and glabrous.

Fruit Characteristics

Fruits are capsules 4.3–8.6 mm long and 3.7–6.0 mm wide that undergo loculicidal dehiscence, carried on pedicels up to 74.6 mm long. The number of seeds per capsule is unknown.

Seed Morphology

Seeds are 0.5–1.1 mm long and 0.2–0.4 mm wide, with a two-layered, reticulate seed coat.

Flowering and Fruiting Period

Ourisia macrophylla flowers from August to April and fruits from October to May.

Chromosome Number

The chromosome number of this species is 2n=48.

Species Endemism

Ourisia macrophylla is endemic to New Zealand.

North Island Subspecies Distribution

The subspecies O. macrophylla subsp. macrophylla occurs on the North Island, in the Gisborne, Volcanic Plateau, Waikato, Taranaki, and southern North Island regions.

South Island Subspecies Distribution

The subspecies O. macrophylla subsp. lactea occurs on the South Island, in the Western Nelson, Marlborough, Canterbury, and Westland regions.

Lower Elevation Habitat

This species most often grows below the bushline, in damp to wet sheltered areas within Nothofagus forest, near cliffs, tracks, streams or waterfalls.

Higher Elevation Habitat

It can sometimes be found just above the bushline in partly shaded to open subalpine scrub or tussuck.

Elevation Range and Abundance

It grows at elevations from 210 to 1,800 m (690 to 5,910 ft) above sea level, and can be very locally common.