Monophyllaea meriraiensis Kiew & S.Julia, 2013

Kiew, Ruth & Sang, Julia, 2013, Two new Monophyllaea (Gesneriaceae) species from Sarawak, Borneo, Phytotaxa 129 (1), pp. 59-64 : 62-63

Monophyllaea meriraiensis Kiew & S.Julia , sp. nov. ( Figure 2 )

Differs from Monophyllaea tenuis in its larger, glabrous lamina twice as long as wide, its long, narrow corolla tube and ovoid ovary with a longer style.

Type:— MALAYSIA. Borneo, Sarawak: Tatau District, Ulu Merirai , Path to Gua Bukit Linggong (2 o 48′34″ N, 113 o 40′ 25″ E), 14 July 2005, Leong et al. PL 330 (holotype SAR!; isotypes K!, L!, SAR!, SING!) .

Stems (hypocotyls) ca. 11 cm long, fleshy, erect, slightly downy white, glabrous, ca. 4 mm diameter when dried, glaucous. Leaves pendent, narrowly ovate, ca. 34.5 × 16 cm, glabrous, thin, brittle, mid green in life, base deeply cordate, lobes to 2 cm long, apex attenuate, beneath encrusted with crystalline chalk pustules, lateral veins 14–24 pairs, 0.5–1.6 cm apart, midrib sunken above with many conspicuous subcutaneous pustules, prominent beneath, tertiary veins prominent, finely reticulate. Inflorescences erect, arising from base of midrib, 1–2 per leaf, more or less even-aged, peduncle ca. 8.5 cm long, hairs simple, sparse, flowering axis ca. 2.5 cm long, flowers arranged in 2 pairs but 1 flower not developing so flowers appear to be arranged in threes, lowest ca. 4 cm apart, upper much closer, pedicels to 10 mm long, glabrous, very slender. Calyx divided nearly to the base, minutely pilose outside, lobes oval, ca. 2 × 1 mm, apex erose. Corolla ca. 6.5 mm long, cream with white lobes, tube narrow, ca. 4 × 1.5 mm, mouth bearded with long hairs, upper lobes orbicular, ca. 1.5 × 1.5 mm, at 45 o to the tube, lateral and median lobes connate, lateral lobes oval, ca. 2.5 × 1.5 mm, median lobes smaller, orbicular, ca. 1.5 × 1.5 mm. Stamens glabrous, filaments more or less straight, posterior ca. 1 mm long, anterior ca. 1.5 mm long, apex broadened and geniculate, anthers globose, ca. 0.5 mm diameter. Disc ca. 0.3 mm high, prominent. Ovary ovoid, ca. 0.75 × 0.5 mm, style ca. 1.5 mm long. Fruit not known.

Distribution:— Endemic to Sarawak, Borneo; known only from the type locality at a limestone area in Ulu Merirai, Tatau district.

Habitat:— On a deeply shaded limestone cliff overhang, at an elevation of 131 m. Presumably rare because only one population was encountered. Its flowering appears to be seasonal because all plants in the population had flowers at the same stage (young buds with a few flowers opened). However, it is not an annual because there are remnants of old peduncles on the large plants.

Notes:— In its thin, relatively narrow leaves and slender erect inflorescences with fine pedicels, this species most resembles Monophyllaea tenuis from the Padawan limestone in the Kuching Division. Interestingly, M. tenuis occupies a similar habitat also being found on sheltered limestone rock faces. However, M. meriraiensis differs from M. tenuis in many lamina and flower characters ( Burtt 1978; Table 2). A few of the larger plants had produced a second or several laminas at the base of the midrib ( Figure 2C ). Unlike most monophyllaeas, the lamina apex was intact and had not rotted away, perhaps suggesting that this is not a long-lived plant.

Figures

FIGURE 2. Monophyllaea meriraiensis Kiew & S.Julia. A. habit; B. leaf with inflorescences; C. newly developed leaves; D. flowers (all photos from PL 330 by P.K.F. Leong).