Erycibe trichocarpa Kochaiph. & Utteridge, 2021

Kochaiphat, Phongsakorn, Traiperm, Paweena & Utteridge, Timothy M. A., 2021, Three new species of Erycibe (Convolvulaceae) from Malesia, Phytotaxa 494 (1), pp. 103-112 : 106-108

2. Erycibe trichocarpa Kochaiph. & Utteridge sp. nov. ( Figs. 1 and 3 )

Type:— INDONESIA. Borneo: West Kalimantan Province, Serawai , Sungai Merah , 0°33’40”N, 112°37’33.7”E, 700 m, 8 February 1995 (fr.), Church, Mahyar & Afriastini 1794 (holotype K!; isotypes BO [1313402]!, GH [ A], L [ L.2734346]!, SING) .

Diagnosis:—Unique in the genus Erycibe on account of the combination of the tree habit, leaves covered with stellate 5–8-branched hairs with the longest central branch of the hairs 0.15–0.4 mm long, and the fruits densely, and conspicuously, covered with short redbrownish hairs. The densely hairy fruit distinguishes Erycibe trichocarpa from all other species of Erycibe in Borneo recorded with a tree or shrubby habit (i.e., not lianas), viz. E. borneensis (Merr.) Hoogland (1953a: 310) , E. bullata Ridl. ex Hoogland (1953a: 311) , E. crassipes Ridl. ex Hoogland (1953a: 312) and E. stenophylla Hoogland (1953a: 317) , which all have glabrous ovaries and fruits. Erycibe trichocarpa is very similar to the other new species described below from Borneo, E. brunneopilosa , in the densely hairy fruits, but differs in its tree habit and the shorter hairs on the fruit.

Small tree to 9 m (fide Church et al. 1794), trunk 12 cm diameter at breast height (dbh); stems terete, young branches densely brownish stellate-hairy, mature stems smooth, whitish-grey, not lenticellate. Leaves simple, petioles 0.4– 0.6 cm long, densely dark-brownish hairy; lamina coriaceous, elliptic, 8–15 × 4–6 cm, base obtuse, apex attenuate, margin entire, slightly revolute, adaxially glabrous, pale green, abaxially densely covered with stellate 5–8-branched hairs, longest central branch 0.15–0.4 mm; midrib adaxially inconspicuous and grooved, abaxially prominent; veins 5–7 on either side, inconspicuous adaxially, prominent abaxially, intercostal veins adaxially inconspicuous, abaxially prominent, reticulate. Inflorescences axillary. Flowers not seen. Fruit a berry, ±globose to oblong-ellipsoid in outline (in sicco), 2.3–2.7 cm long, 1.7–2.0 cm diam., densely covered with red-brownish hairs.

Distribution:— Endemic to Indonesian Borneo, currently only known from the type collection from West Kalimantan Province.

Habitat:— Growing on a “sloped hill below ridge, semi-light exposed” in hill dipterocarp forest; elevation 700 m.

Preliminary conservation assessment:— Data Deficient ( DD) following the IUCN categories ( IUCN 2012). Only one specimen has been collected to date, and the collection notes state ‘seldom’, indicating, that whilst more than one individual was seen, the species was not common in the Sungei Merah area . More data and observations are needed before the species can be formally assessed .

Etymology:— The specific epithet refers to the hairy fruit.

Notes:— The densely hairy fruits and tree habit are unique in Malesian Erycibe , and E. trichocarpa is unlikely to be confused with any other species in Borneo. Unfortunately, as the only specimen is without flowers, the new species cannot be keyed out in the Flora Malesiana account by Hoogland (1953c), but E. trichocarpa is most similar to E. borneensis in the oblong leaves and arborescent habit. Whilst the genus predominantly comprises climbing species capable of becoming large woody canopy lianas, there are a several species that are trees and shrubs—this life form is not age-dependent as they remain as trees throughout their life cycle with a well-defined trunk reaching up to 16 m in height. The Erycibe tree taxa in Borneo all have glabrous ovaries and fruits, viz. E. borneensis , E. bullata , E. crassipes and E. stenophylla . Erycibe trichocarpa differs from these glabrous-fruited species in having larger fruit (2.3–2.7 mm long) than E. borneensis (0.5–1.5 mm long), while both E. bullata and E. crassipes have much larger leaves ( E. crassipes 16–37 cm long; E. bullata 18–25 cm long v. 8–15 cm long in E. trichocarpa ). Erycibe stenophylla is a distinct shrubby rheophyte with linear-lanceolate leaves usually less than 2 cm wide (see Hoogland 1953c: 415, fig. 16).

The authors were initially surprised when reading the label for the first time indicating this species was a “small tree, to 9 m tall” because no tree species has been described with dense hairs on the fruit. We are confident that E. trichocarpa is a tree species because the leaf morphology (oblong, drying dull olive-green above and paler below, as well as the distinctive narrow, oblong herbivore tracks) resembles that of other tree species, especially E. borneensis and E. bullata — specimens of both are usually dry olive-green and often have distinctive oblong herbivore tracks (visible in the following specimens of E. borneensis: Laman et al. 835 [L.2741647], Pereira et al. 780 [L.3765912]; and E. bullata: Mohtar S. 48158 [L.2741564], Paie S.24283 [L.2741569]). Climbing species generally dry a sandy to dark brown and have more randomly shaped herbivore damage when present. In addition, the collection notes are quite specific detailing the tree habit and height, dbh, bark characters as well as the leaf and fruit indumentum, and the specimen was distributed as ‘ Erycibe sp. nov. ’ by the first collector who had already collected E. borneensis (Church et al. 1995 [L.2734316]). in the same region and understood variation in the genus, including the unique arborescent habit of this Erycibe .

Figures

FIGURE 1. Distribution of Erycibe sangiheensis (star), E.trichocarpa (triangle), E.brunneopilosa (circle).Map made using Simplemappr (https://www.simplemappr.net).

FIGURE 3. Erycibe trichocarpa Kochaiph. & Utteridge. A Habit, flowering branch B Young branch C Adaxial surface of lamina and midrib, detail D Abaxial surface of lamina and midrib E Hairs from abaxial surface of lamina F Fruit hairs, side view. Drawn by Naoko Yasue from Church et al. 1794 (K).