Cyrtandra purpurea 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 : 87-89

28. Cyrtandra purpurea H.J.Atkins , Edinburgh J. Bot. 60(3): 313 (2004).

– Type: Indonesia, Sulawesi, Central Sulawesi, Upper Sopu River , 25 v 1979, van Balgooy 3503 (holotype L; isotypes A, BO, E). Figure 44 .

Branching, climber or epiphytic shrub (height not recorded). Stems striate, subglabrous. Leaves opposite, subequal; petiole 10–20 mm long, glabrous; blades 17–22 × 4–5 cm, narrow oblong, base acute, margin entire, apex acuminate; 11–14 pairs of lateral veins, not reaching margin, tertiary venation faint on herbarium specimens, glabrous above, sparsely hairy on midrib and veins below. Inflorescences axillary, sessile, 1- or 2-flowered, from near apex to base of stem; bracts not seen (soon caducous?); pedicels up to 15 mm long, extending in fruit, glabrous. Calyx tubular, purple, coriaceous, 10–11 mm long, 5-lobed, slightly bilabiate, lobes triangular, 5 mm long, glabrous. Corolla purple to brown, c. 30 mm long, tubular, glabrous externally, mouth oblique, limb strongly bilabiate, lower median lobe linear and strongly recurved, c.8 × 1.5 mm, upper and lateral lobes recurved, 2–3 mm long. Stamens with filaments c. 20 mm long, attached c. 10 mm from base of corolla; anthers not seen (damaged on all specimens); staminodes 3, lateral staminodes c. 1 mm long, central staminode minute, barely visible. Gynoecium c. 35 mm long; disc cupular, margin subentire to undulate, c. 1 mm long, glabrous; ovary glabrous; style glandular hairy for much of its length; stigma peltate, c. 2 mm across, exserted. Fruits subglobose, fleshy, 10–17 × 10–12 mm, green when unripe, glabrous, calyx not persistent, base of style persistent.

Distribution. Central Sulawesi (see Figure 47 ).

Habitat and ecology. Upland forest at an altitude of 940–1000 m.

Etymology. This species is named for the unusual purple colour of its corolla ( Atkins, 2004).

Proposed IUCN conservation category. The low number of collection localities gives an AOO of 8 km 2, based on a 2 × 2 km grid cell size ( Bachman et al., 2011). This species has been collected on only two occasions despite this being one of the better-collected areas of Sulawesi, suggesting that the small AOO is fairly accurate. All the collections were made between 940 and 1000 m in upland forest, which is one of the more threatened forest types on the island ( Cannon et al., 2007), and although the collection localities are within the Lore Lindu National Park, satellite imagery show signs of habitat degradation and land conversion in at least one of these sites, suggesting a negative population trend. Cyrtandra purpurea is therefore assessed as Endangered (EN) B2ab(iii).

Additional specimens examined. INDONESIA. Central Sulawesi. Sigi: Sopu Valley , 1000 m, 3 v 1979, van Balgooy 3124 ( A, BO, E, L) ; Kec Palolo, Kamarora, Mt Potong , 940 m, 17 xi 2000, Kessler PK 2892 ( K, L) ; Sopu Valley , 1000 m, 6 v 1979, de Vogel 5231 ( BO, K, L) .

Cyrtandra purpurea is very distinctive due to its climbing or epiphytic habit, subglobose fruit, purple flowers with characteristic elongated lower lobe, and leathery oblong leaves with obscure tertiary venation. There is a collection from Mount Potong whose label states that there are four seeds in the fruit, which would not be correct for Cyrtandra . It has not been possible to dissect the fruit to confirm this, but we have assumed that the label information is incorrect, being possibly based on the observation of the four intrusive arms of the placentae in an immature fruit.

Figures

Figure 44. Cyrtandra purpurea. a, Habit; b, side view of corolla; c, opened calyx, showing inner surface; d, opened corolla, showing position of stamens and staminodes; e, gynoecium including disc. Drawn by Christina Oliver from van Balgooy 3503. Reproduced from Atkins (2004) with the permission of the Trustees of the Royal Botanic Garden Edinburgh.

Figure 47. Distribution of Cyrtandra purpurea (black triangles) and C. purpureofucata (white circles).