Ipomoea inaccessa J.R.I.Wood & Scotland

Wood, J.R.I., Martinez Ugarteche, M.T., Muñoz-Rodríguez, P. et al. (2018). Additional notes on Ipomoea (Convolvulaceae) in Bolivia. Kew Bulletin 73: 57. https://doi.org/10.1007/s12225-018-9784-z

Type

Bolivia. Dept. La Paz, Prov. Caranavi, on W side of Serrania de Bellavista, above Carrasco, J. R. I. Wood & S. G. Beck 28539 (holotype LPB; isotypes K, OXF, USZ).

Morphology General Habit

Liana, 15 – 20 m high, the flowers covering the tops of trees; stems, when young green, minutely puberulous, weakly angled; when mature woody, grey, somewhat muricate, glabrescent; rootstock (juvenile) tuberous

Morphology Leaves

Leaves petiolate, 5.5 – 14 × 3 – 8 cm, ovate, cordate, acuminate, both surfaces minutely and densely puberulent, abaxially paler with rather prominent, raised veins; petioles 2.5 – 6 cm, minutely puberulent

Morphology Reproductive morphology Inflorescences

Inflorescence of (1 –) 2 – 4 (– 7)-flowered, pedunculate, axillary cymes; peduncles 2.5 – 11 cm, minutely puberulent; bracteoles at base of cyme resembling small leaves, upwards caducous, not seen; secondary peduncles 0.5 – 4 cm; pedicels 1.5 – 3.5 cm, minutely puberulent; sepals slightly unequal, somewhat convex, outer 13 – 16 × 10 mm, inner 18 – 20 × 15 – 18 mm, elliptic to subovate, rounded, rigid, glabrous, pale green with scarious margins; corolla 9 – 9.5 cm, funnel-shaped, white with pale pink throat or pure white, glabrous; limb unlobed, c. 6 cm wide; filaments unequal, 15 – 24 mm long, anthers 10 mm long; style 3 cm long; stigma biglobose

Morphology Reproductive morphology Fruits

Capsule subglobose, 18 × 15 mm, glabrous; seeds 8 × 4 mm, pilose on the margins with hairs up to 12 mm long.

Note

A very vigorous liana reaching heights unattained by most species of Ipomoea. Herbarium specimens are most likely to be confused with I. philomega (Vell.) House but that species has smaller, deep pink corollas, 5 – 6 cm in length and, usually, glabrous leaves and distinctive reddish sepals. I. inaccessa has a larger corolla about 9 cm long, which is white or white with a pale pink throat. Its leaves are uniformly densely puberulent on both surfaces and the sepals are pale green. The flower colour and sepal shape suggest it is related to I. reticulata O’Donell and I. saopaulista O’Donell and this is confirmed by unpublished molecular sequence data. However, the much larger dimensions of the sepals (13 – 20 mm long, not 7 – 10 mm) and corolla (9 – 9.5 cm long, not 2.5 – 5 cm) rule out both these species. This species is named Ipomoea inaccessa because of the difficulties of collecting flowering specimens from high forest on precipitous wooded Andean slopes.

Ecology

Endemic to moist hill forest with frequent cloud at 1400 – 1500 m.

Distribution

Bolivia, on the west side of the Serrania de Bellavista in Caranavi Province of the La Paz Department.

Conservation

This is a narrowly endemic species, known only from a single area of the Serrania de Bellavista. This is a large ridge, reaching about 2000 m in height, covered in moist hill forest. The habitat is vulnerable but the very steep slopes, the very moist, cloudy climate and its unsuitability for agriculture provide a degree of protection. Careful population studies are needed to assess the extent of populations of Ipomoea inaccessa in the area as the Serrania is extensive and mostly botanically unknown. It can only be treated as Data Deficient (DD) within IUCN guidelines until its populations are carefully studied.

Phenology

Flowering presumably begins in March and continues into May with mature fruit present in July.