Cyrtandra hekensis Karton. & H.J.Atkins

Atkins, H. J. & Kartonegoro, A., 2021, A TAXONOMIC REVISION OF CYRTANDRA (GESNERIACEAE) IN SULAWESI, INDONESIA, Edinburgh Journal of Botany 78 (364), pp. 1-122 : 49-51

13. Cyrtandra hekensis Karton. & H.J.Atkins , Edinburgh J. Bot. 75(2): 182 (2018).

– Type: Indonesia, Sulawesi, Central Sulawesi, Mt Hek , 9 iv 2008, Thomas & Ardi 08-26 (holotype BO, isotype E). Figure 26 .

Herb to 25 cm in height. Stems ridged, striate, upper stem appearing reddish, from dense, coarse indumentum on young growth, older stems glabrous. Leaves opposite, slightly unequal; those of a pair well developed but one slightly smaller; petioles 0.8–2 cm long, densely, coarse-hairy on young growth becoming glabrous on older growth; blades 7–7.5 × 1.6–3 cm (larger leaves), 3.5–5 × 1.3–1.7 cm (smaller leaves), narrow elliptic or oblong to somewhat oblanceolate, base decurrent, only narrowly winged at base, margin serrate, apex acuminate; 4–6 pairs of lateral veins and reticulate tertiary venation; dark green and mostly glabrous above with some hairs towards the base, paler green and with scattered hairs below with coarse hairs on the midrib and veins. Inflorescences axillary, subsessile to shortly pedunculate, 1- or 2-flowered; peduncles red, 2–3 mm long, hairy; bracts green, 9 × 5–6 mm, ovate, connate c. 4 mm from base, with some coarse hairs on midrib and margins, margin slightly serrate; bracteoles paired, green, 6–8 × 3 mm, oblong, with coarse hairs on midrib and margins; pedicels 2–3 mm long, glabrous. Calyx tubular, pale green, 10–11 mm long, upper lobes c. 2 mm long, lower lobes c. 3 mm long, acuminate, glabrous except for a few tufts of hair at apex. Corolla white with greenish yellow markings in throat, c. 15 mm long, tube narrow in lower 1/3, widening to mouth in apical 2/3, hairy externally in the apical 1/3, particularly densely so towards the mouth, upper lobes rounded, 3–4 × 3 mm, lower and lateral lobes rounded, c.3 × 3 mm. Stamens with filaments c. 5 mm long, attached c. 6 mm from base of corolla, glabrous; anthers c. 1 mm long, coherent at apices; staminodes 2, c. 0.5 mm long. Gynoecium c. 10 mm long; disc cupular with lobed margin, glabrous externally, c. 1.5 mm long; ovary glabrous, style eglandular hairy towards apex; stigma slightly bilobed, lobes small, c. 1 mm across. Fruits ovoid, glabrous, verrucose, drying light brown, 6 × 4 mm; base of style and calyx persistent, bracts sometimes persistent.

Distribution. Central Sulawesi (see Figure 29 ).

Habitat and ecology. Hill forest at an altitude of 420– 660 m.

Etymology. This species is named after the mountain on which it was collected ( Kartonegoro et al., 2018).

Proposed IUCN conservation category. The low number of collections for Cyrtandra hekensis means that it is not possible to calculate an EOO, but it has an AOO of 4 km 2, based on a 2 × 2 km grid cell size, under the B criteria ( Bachman et al., 2011). The species is known only from Mount Hek, Banggai Regency, where it was collected at relatively low altitude during expeditions in 2004 and 2008. This forest type is one of the most threatened in Sulawesi ( Cannon et al., 2007) and Mount Hek is in an area with no formal protection (UNEP-WCMC & IUCN, 2019). It is, however, in one of the most under-collected areas of Sulawesi ( Kessler et al., 2002; Cannon et al., 2007), and it is possible that there are more populations of this species. To reflect its narrow distribution in a single location in a threatened forest type and lack of formal protection ( Cannon et al., 2007), Cyrtandra hekensis is assessed as Critically Endangered (CR), B2ab(iii). Habitat protection and ex situ conservation are recommended.

Additional specimen examined. INDONESIA. Central Sulawesi. Banggai: Mt Hek , 26 ii 2004, Hendrian, Newman, Scott, Saleh & Supriadi 901 (E) .

Cyrtandra hekensis is most similar to the widespread C. polyneura in its subequal, decurrent leaves, bracteate inflorescence, and white flowers with greenish yellow markings in the throat but can be distinguished by its much smaller, narrower leaves, fewer flowers per inflorescence, and coarser indumentum on young growth.

Figures

Figure 26. Cyrtandra hekensis. a, Habit; b, opened corolla, showing position of stamens and staminodes; c, opened calyx, showing inner surface; d, side view of corolla; e, gynoecium, showing disc and top of pedicel; f, fruit with persistent calyx partially removed; g, bracts. Drawn by Claire Banks from Hendrian et al. 901. Reproduced from Kartonegoro et al. (2018) with the permission of the Trustees of the Royal Botanic Garden Edinburgh.

Figure 29. Distribution of Cyrtandra gorontaloensis (black diamonds), C. hekensis and C. hendrianii (green star) and C. hispidula (black triangle).