Description

Key Characters:

Growth Form: Plants 1.2–2.1 m tall.

Stems: Stem 1–1.3 cm diam. glabrous, cicatrices semi–circular, shallowly obtriangular, or widely obtrullate, 2.5–4.5 mm tall, 3.5–5 mm wide.

Roots: Roots mycotrophic via vesiculararbuscular mycorrhizae (Koske et al. 1992).

Leaves: Leaves simple. Alternate, forming a dense spherical, oblate, or cylindrical apical rosette. Blades oblanceolate, 15–19 × 1.6–2.3 cm, 9–10 times longer than wide. Apex acuminate. Base attenuate, sometimes quite petiole-like, in other cases the differentiation of a petiole very indefinite and the leaf clearly sessile. Surfaces glabrous; blades coriaceous. Margins crenulate. Stipules absent.

Flowers: Flowers in racemes glabrous, each 25–30–flowered; peduncle 10–15 cm long; sterile bracts oblanceolate, narrowly elliptic, or linear, 30–120×4–16 mm, the margin crenulate or entire, the apex acuminate; rachis 14–26 cm long; floral bracts narrowly oblong or linear, 15–35×3–4.5 mm, the margin crenulate or subentire, the apex acute; pedicels 20–26 mm long; bracteoles oblong or elliptic, 2–3 mm long; hypanthium hemispheric, 5–7 mm long, 6–8 mm diam. 1/12–1/10 as long as the corolla; calyx lobes triangular, oblong, or ovate, erect, 4.5–7×1.8–2.8 mm, 2/3 as long as to equaling the hypanthium, the margin entire, the apex obtuse or acute. Flowers tetracyclic, bisexual (perfect), protandrous, zygomorphic, epigynous, pedicellate, resupinate, ornithophilous, large. Calyx synsepalous; tube glabrous, adnate to the ovary, forming a hemispheric, campanulate, oblate, obovoid, ovoid, or ellipsoid appendicular hypanthium 1/12–1/6 as long as the corolla; lobes 5, valvate, triangular, oblong, linear, ovate, lanceolate, or narrowly elliptic, 3/5 as long as the hypanthium to nearly 3 times as long, the dorsal sometimes a bit longer than the ventral, erect or ascending (spreading in T. kauaiensis), caducous from the young fruit, minutely auriculate in T. auriculata, the margin entire (rarely sparsely denticulate and/or ciliate toward apex), the apex round, obtuse, acute, or acuminate and sometimes apiculate. Corolla subbilabiate, pink, 70–73 mm long; tube gently curved, 34–40 mm long, 4–7 mm tall at middle, 3–5.5 mm tall at mouth, 6.7–12.3 times longer than height at middle; dorsal lobes 31–37×1–2.2 mm, ¾ as long as the tube to a bit longer, the apex acuminate; ventral lip obovate or widely elliptic, 27–32×4–8 mm. Stamens 5, antisepalous, connate distally for most of their length; Staminal column strongly exserted, emerging above the dorsal lobes; filament tube 57–62 mm long, 3.7–4.3 times longer than dorsal anthers, sparsely to densely pubescent toward the apex; anther tube 3–3.8 mm diam. pubescent at base; dorsal anthers 14–16 mm long; ventral anthers 10–12 mm long, with tufts of white trichomes 1.5–2.5 mm long at apex. Pollen grains 41–44 μm polar diam. 27–30 μm equatorial diam. prolate, tricolporate, the exine shallowly and minutely reticulate (Selling, 1947). Ovary inferior, 2-loculed, adnate to the hypanthium, flat at apex; placentae axile; ovules numerous; style 1, slender, terete (cylindrical), with a ring of stiff white hairs near the apex; stigma 2-lobed, the lobes appressed and non–receptive as the style grows through the anther tube, pushing out pollen, after which the stigmas spread and become receptive.

Fruit: Capsules broadly depressed oblate; 7–10 mm long; 11–12 mm wide; 7–9 mm thick; the pores numerous and scattered over the entire lateral surface. Seeds 1–1.1×0.4–0.5 mm.

Ploidy:

Habitat: Endemic to the Wai‘anae Mountains of O‘ahu; primarily on the upper slopes and summit of Ka‘ala; growing in montane wet shrubland.

Elevation Range: 1160–1225 m.