Codonoboea personatiflora (Gesneriaceae), a new species from Peninsular Malaysia

Abstract Codonoboea personatiflora Kiew & Y.Y.Sam, sp. nov., is described from lowland forest in the foothills in Terengganu, Peninsular Malaysia. It is unique in the genus in its personate flower. Its conservation status falls within the IUCN Endangered category.


Introduction
Th is striking new species has attracted attention for a number of years for its tall bushy habit and glossy young leaves conspicuously reddish towards the base and bright yellowish green towards the apex. However, it was only when it was cultivated in the nursery of the Forest Research Institute Malaysia in Kuala Lumpur that fl owering material could be obtained and the species described. It belongs to Codonoboea, a genus of about 120 species that is an important component of the herb layer in rain forest in W Malesia extending as far north as Southern Th ailand and as far south as Sulawesi (Kiew and Lim 2011). Its centre of distribution with 79 species is Peninsular Malaysia where it is found in abundance and diversity (Kiew 2009). Recent molecular phylogenetic analyses (Weber et al. 2011) have confi rmed that Codonoboea is monophyletic and is a genus distinct from Didymocarpus (Weber and Burtt 1983), Henckelia and Loxocarpus (Weber and Burtt 1998). It is unique among Codonoboea species in its personate (closed) fl ower. Robust, erect, unbranched herb. Stem woody to 65 cm tall, fl owering at ca 15 cm tall, bare stem below the leaves 4-9 mm diam. Leaves opposite, pairs equal, spaced 8-17 mm apart, glossy when young, reddish towards the base and bright yellowish green toward apex, older leaves uniformly dull greyish green above; petioles 1.3-3 cm long, slightly grooved above, minutely pubescent; lamina oblanceolate, thinly leathery, 15-34 × 4-8 cm, lateral veins whitish or yellowish green, sometimes with a silvery band along the midrib, paler beneath, base narrowed then slightly rounded, margin serrate in the upper half, teeth ca 1 mm long, apex narrowly acuminate, acumen to 1-2.5(-4) cm long; midrib and veins impressed above, prominent beneath in life, lateral veins 9-20 pairs, ferrugineous beneath.
Distribution. Peninsular Malaysia, endemic in the state of Terengganu. Ecology. In primary or logged-over lowland mixed dipterocarp forest at low altitudes (below 100 m), on shaded hillsides or slopes, often above streams.
Etymology. Named for its personate (closed) fl ower that is unique for the genus. Conservation status. EN B2a,b(ii,iii). Following the IUCN Criteria and Categories (IUCN 2001;Chua 2010), this species falls within the Endangered Category because it is known from fi ve localities, has in total an area of occupancy of 28 sq km. In addition, it is nowhere found within Peninsular Malaysia's network of Totally Protect- ed Areas and it grows at low altitudes in lowland forest, a habitat that is threatened by or already has been logged or is threatened by forest clearance for oil palm plantations.
Other inconspicuous bracts, and medium-sized (to 2 cm long) fl owers (Ridley 1923). However, it diff ers from the other species in this section, and indeed from all other known Codonoboea species, in its personate fl ower. Th e special feature of this fl ower is the lower lip where the recurved lobes form a rim that is pressed upwards against the upper lip and so closes the corolla mouth, unlike the usual open funnel-or trumpet-shaped or campanulate corolla of Codonoboea species. In addition, the aperture is fi lled by the long hairs, a feature not seen in other Codonoboea species. Th e lower lip appears to be hinged because it is readily bends downward when pressure is applied so opening up the mouth of the corolla tube.
Th e majority of Codonoboea species are nectar fl owers (the cylindrical nectary surrounding the base of the ovary supplies nectar as the reward for the pollinator) with a narrow tubular fl ower that is strongly dilated to produce an open funnel-or trumpetshaped fl ower, often with the lower lobes projecting and forming a landing platform for the insect pollinator. Usually there are yellow or orange nectar guides on the fl oor of the tube. Th e fl ower is therefore open to any insect small enough to enter the tube. Although there are very few observations on pollination in this genus, bumblebees (Bombus sp.) have been observed visiting two species, C. hispida (Ridl.) Kiew and C. robinsonii (Ridl.) Kiew, both belonging to Codonoboea sect. Didymanthus (Kiew 2009) and it is likely, based on fl oral morphology, that bees are the pollinators of most of these Codonoboea species. Th e other type of fl ower seen in the genus is the smaller, short-tubed, often campanulate pollen fl ower where the anthers are large and conspicuous in the mouth of the corolla. Th ese fl owers either have very small nectaries or none at all and pollen is off ered as the reward.
Th is new species is obviously a nectar fl ower but is unique in Codonoboea in that the upper and lower lips fi t closely together so that the mouth is closed and in addition there is a tangle of long hairs just inside the mouth that might prevent small insects from squeezing between the lips. Th is personate fl ower closely resembles that of the ornamental snapdragon, Antirrhinum majus L. (Scrophulariaceae) that is pollinated by bumblebees that on landing on the fl ower are suffi ciently heavy to depress and open the lower lip.
Th ere are only two other examples of this type of personate fl ower in Malaysian Gesneriaceae, namely in Didymocarpus antirrhinoides A.Weber (Weber and Burtt 1983) that has a fl ower of similar size (15-23 mm long) and Rhyncholossum medusothrix B.L.Burtt (Burtt 1962) with a corolla tube 10-25 mm long that in addition has 'medusoid' hairs in the throat. However, for none of these personate fl owers is the pollinator known.
Plan Development Project entitled "Dokumentasi dan Inventori Flora Malaysia". We thank the KEP herbarium staff for their support in the fi eld and to P.T.Ong and the nursery staff for maintaining the living collection and to Dr L.S.L.Chua for assessing the conservation status. We are indebted to P.T.Ong for the photography, to C.L.Lim for the preparation of maps, and to the curators and staff of the BM, E, K, KLU, L and SING herbaria for permission to examine specimens in their care. Open access to this paper was supported by the Encyclopedia of Life (EOL) Open Access Support Project (EOASP).