Pro ofs Studies in Malesian Gentianaceae , VI . A revision of Utania in the Malay Peninsula with two new species

In light of the molecular phylogenetic studies of the Fagraea complex by Sugumaran & Wong (2012), it was possible to circumscribe various genera based on monophyletic groups, each of which was distinguishable by a number of morphological characters. In the taxonomic framework proposed by Wong & Sugumaran (2012), the earliest valid name for the Racemosa clade, previously treated as Fagraea section Rac­ emosae Benth. (Bentham 1856: 99) in the broad concept of Leenhouts (1962), was identified as Utania Don (Don 1838: 663). Three other clades that were obtained in their analyses (viz., the Fagraea, Gigantea and Elliptica clades), and the isolated F. crenulata Maingay ex Clarke (Hooker 1883: 83) lineage, were, respectively, distinguished as Fagraea Thunb. sensu stricto (Thunberg 1782: 132), Cyrtophyllum Reinwardt (Reinwardt 1825: 8), Picrophloeus Blume (Blume 1826: 1019), and Limahlania K.M.Wong & Sugumaran (Wong & Sugumaran 2012: 491). Among members of that complex, Utania appears to be very well distinguished from the other genera by Roux’s tree architectural model (Hallé et al. 1978), in which the main orthotropic (stem) axis shows continuous growth with decussate phyllotaxis, and the branches are plagiotropic with the leaf pairs in a single plane. The distichously arranged leaves on the branches are easily observed even in herbarium material. In all the other genera of this complex, stem growth is episodic and the branches variously form orthotropic complexes (Fagraea s.s. and Picrophloeus), or extend plagiotropically by apposition (Cyrtophyllum) or through modular growth (Limahlania); also the leaves on branches are decussate (Wong & Sugumaran 2012). Species of Utania do not produce resin at their vegetative terminal buds or a gummy translucent or creamy latex in their fruit epidermis and fruit wall, as can be found in the other genera of the Fagraea s.l. complex. The inflorescence of Utania is generally a pendulous elongate panicle with cymose branching, in which the branch pairs are condensed and distinctly shorter than the rachis; here we use the term ‘rachis’ for the main inflorescence axis distal to the peduncle, as defined by Jackson (1928) and Beentje (2012). The other genera mentioned bear only a solitary flower or branched cymes where the basal branches are nearly as long as the rachis. Fruits of Utania (both fresh or dried) have a firm fruit wall and epidermis that does not come off easily, whereas in the other genera the fruit wall is relatively soft at maturity, with the epidermis coming off easily and often wrinkled in dried material. Fagraea section Racemosae was revised for Borneo by Wong & Sugau (1996), and the required nomenclatural transfers to Utania for Bornean taxa are validated in Wong et al. (2013). The present contribution is a revision of the genus for the Malay Peninsula.

Among members of that complex, Utania appears to be very well distinguished from the other genera by Roux's tree architectural model (Hallé et al. 1978), in which the main orthotropic (stem) axis shows continuous growth with decussate phyllotaxis, and the branches are plagiotropic with the leaf pairs in a single plane.The distichously arranged leaves on the branches are easily observed even in herbarium material.In all the other genera of this complex, stem growth is episodic and the branches variously form orthotropic complexes (Fagraea s.s. and Picrophloeus), or extend plagiotropically by apposition (Cyrtophyllum) or through modular growth (Limahlania); also the leaves on branches are decussate (Wong & Sugumaran 2012).
Species of Utania do not produce resin at their vegetative terminal buds or a gummy translucent or creamy latex in their fruit epidermis and fruit wall, as can be found in the other genera of the Fagraea s.l.complex.The inflorescence of Utania is generally a pendulous elongate panicle with cymose branching, in which the branch pairs are condensed and distinctly shorter than the rachis; here we use the term 'rachis' for the main inflorescence axis distal to the peduncle, as defined by Jackson (1928) and Beentje (2012).The other genera mentioned bear only a solitary flower or branched cymes where the basal branches are nearly as long as the rachis.Fruits of Utania (both fresh or dried) have a firm fruit wall and epidermis that does not come off easily, whereas in the other genera the fruit wall is relatively soft at maturity, with the epidermis coming off easily and often wrinkled in dried material.
Fagraea section Racemosae was revised for Borneo by Wong & Sugau (1996), and the required nomenclatural transfers to Utania for Bornean taxa are validated in Wong et al. (2013).The present contribution is a revision of the genus for the Malay Peninsula.
tropic, monopodial, with continuous growth; developing branches that are plagiotropic (Roux's architectural model fide Hallé et al. 1978); bark becoming fissured in older trees.Vegetative shoot apices non-resinous.Leaves on orthotropic (stem) axes decussately arranged, those on plagiotropic branches distichously arranged; margin entire; petiolar sheaths of a leaf pair fused to form a shallow cup-like ochrea that loosely clasps the stem; petiolar base auricles absent.
Inflorescence terminal, a many-flowered and branched pendulous cyme.Flowers bisexual, small to medium-sized, up to 25 mm wide at the mouth; calyx lobes 5; corolla white to creamy white, corolla lobes 5, overlapping to the right; stamens 5, typically not to slightly exserted; anthers versa- Small tree, c. 2 m tall.Leaves elliptic-ovate to ellipticlanceolate; (4.3-)8-11(-14.7)cm long, (1.2-)3-5.5 cm wide; base cuneate rounded; apex acuminate-short caudate; margin flat; thin coriaceous; glabrous on both surfaces; midrib prominent below, sunken above; secondary veins 4-6 pairs, upper side faint, lower side faint to slightly prominent; tertiary veins inconspicuous; petioles 8-15 mm long, 1-2 mm diam.Inflorescence terminal, a many-flowered panicle, (2.4-)3.5-6(-9)cm long; peduncle 2.8-4.5(-6)cm long, 1-1.5 mm diam.; rachis in the distal half of the flower-bearing part of the inflorescence not conspicuously thicker than the proximal part and the peduncle, clearly visible; branch tiers closely spaced (except sometimes the lowest two tiers well-spaced, (0.5-)1-2(-2.5) cm apart), the basal 1-2 branch tiers most branched, typically to 1-2 orders, more distal tiers hardly so.Flower pedicel 2-4 mm long, 1-1.5 mm diam.; calyx (from the base to the lobe apices) 3-4 mm long, glabrous, calyx cup 3-3.5 mm diam., calyx lobes erect and tightly clasping the corolla tube, 2-3 mm long, 2-2.5 mm wide, margins glabrous to sparsely minute-ciliate or apparently laciniate (the cilia or lacinia just c. 0.1 mm long); corolla narrowly infundibular (the mouth less than to about 3 times the diam. of the lower narrowed part of the tube); white; lower subcylindrical part of the corolla tube 10-13 mm long, 2-3 mm diam., upper flared part of the tube slightly inflated, 10-12 mm long, 6-7 mm diam.at the top; corolla lobes broad-obovate to suborbicular, 2-2.5 mm long, 2.5-3 mm wide; stamens inserted at the upper portion of the lower narrowed tubular part of the corolla tube or the lowermost portion of the upper flared part of the corolla tube; filaments 15-16 mm long, slightly protruding to 5 mm from the corolla mouth in the open flowers; anthers 1.5-2 mm long, c. 1 mm wide, each theca somewhat ellipsoid; style 20-28 mm long, not to slightly protruding to 3 mm from the corolla mouth; stigma shallowly 2-lobed, the lobes broadly suborbicular and recurving when receptive (sometimes resembling a somewhat peltate structure c. 1 mm diam.).Infructescence peduncle 2.2-3.5 cm long, 1-1.5 mm diam.; rachis in the distal half of the fruit-bearing part of the infructescence not conspicuously thicker than the proximal part and the peduncle, clearly visible.Fruit apex beaked; smooth; when mature to 10-11 mm long, 7-10 mm diam.; the base tightly clasped by the calyx lobes.Seeds usually slightly elongated; 1-1.2 mm long, 0.5-1 mm diam.Fig. 1.Habitat and distribution -Tropical evergreen lowland rainforest understory, on granitic and alluvial soils.Endemic to the southern half of the Malay Peninsula, uncommon.Etymology -The Latin 'austromalayensis' refers to its distribution in the south of the Malay Peninsula.Notes - Leenhouts (1962) in his account for the Malesian region, adopted a very broad concept for Fagraea rac emosa (= Utania racemosa) where he dismissed a number of previously described species.Wong & Sugau (1996), in their account for Borneo, resurrected F. peninsularis (= U. peninsularis) among various other species from the synonymy of F. racemosa (U. racemosa).However, their concept of F. peninsularis (= U. peninsularis) (Wong & Sugau 1996) was mixed with material here considered to represent a different species (see also U. peninsularis below).The essential differences between these two species are as follows.
In Utania peninsularis the upper inflated part of the corolla tube is shorter than the lower narrowed tubular portion, whereas in U. austromalayensis, the two parts are about the same length.The peduncle is only up to 1.8 cm long in U. peninsularis but 2.8-6 cm long in U. austromalayensis.The number of secondary veins also differs between these two species: 3-4 pairs in U. peninsularis and 4-6 pairs in U. austromalayensis.
Small to medium-sized tree, usually to 5-15 m (occasionally to 30 m) tall; trunk to c. 15 cm diam.; bark slightly to deeply fissured, dark grey to dark brown.Leaves elliptic to elliptic-lanceolate; (6-)17-24(-28) cm long, (2.5-)6-9 (-10.5)cm wide; base cuneate rounded; apex acuminate to short-caudate; margin recurved (in dried specimens); thickcoriaceous; glabrous on both surfaces; midrib prominent below, sunken above; secondary veins 6-8 pairs, faint on both sides; tertiary veins inconspicuous; petioles 1.2-2.4cm long, (3-)5-7 mm diam.Inflorescence terminal, a many-flowered panicle, (7-)9-12(-15.5)cm long; peduncle (4-)5-8(-9) cm long, 2.5-4(-4.5)mm diam.; rachis in the distal half of the flower-bearing part of the inflorescence not conspicuously thicker than the proximal part and the peduncle, clearly visible; branch tiers well-spaced, 1.5-2.5 cm apart, the basal 1-2 branch tiers most branched, typically to (1-)2 orders, more distal tiers hardly so.Flower pedicel (6-)10-18 mm long, 2-4 mm diam.; calyx (from the base to the lobe apices) 9-13 mm long, glabrous, calyx cup 7-12 mm diam., calyx lobes erect and tightly clasping the corolla tube, 8-11 mm long, 6-10 mm wide, margins glabrous to sparsely minute-ciliate or apparently laciniate (the cilia or lacinia just c. 0.1 mm long); corolla broadly infundibular (the mouth more than 3-4 times the diam. of the lower narrowed part of the tube); cream to white; lower sub-cylindrical part of the corolla 3-4 mm long, 4-6 mm diam., upper flared part of the tube slightly inflated, (13-)15-18(-21) mm long, 17-22(-25) mm diam.at the top; corolla lobes broad-obovate to suborbicular, 12-14 mm long, 10-14 mm wide; stamens inserted at the upper portion of the lower narrowed tubular part of the corolla tube or the lowermost portion of the upper flared part of the corolla tube; filaments 19-23 mm long, not to slightly protruding to 3 mm from the corolla mouth; anthers 3-4 mm long, 1.5-2 mm wide, each theca somewhat ellipsoid; style 12-23 mm long, not protruding from the corolla mouth; stigma shallowly 2-lobed, the lobes broadly suborbicular and recurving when receptive (sometimes resembling a somewhat peltate structure 1-2 mm diam.).Infructescence peduncle 7-8.5 cm long, 3-4 mm diam.; rachis in the distal half of the fruit-bearing part of the infructescence not conspicuously thicker than the proximal part and the peduncle, clearly visible.Fruit ellipsoid, apex beaked; smooth; when mature to 15-18 mm long, 7-10 mm diam.; the base tightly clasped by the calyx lobes.Seeds usually slightly elongated; 1-1.2 mm long, 0.5-1 mm diam.Habitat and distribution -Primary and secondary tropical evergreen lowland rainforests, on granitic and alluvial soils.Malay Peninsula and Sumatra, common.Notes -The flowers are fragrant (Whitmore FRI 20019).Among the six Peninsular Malaysian species in this genus, U. maingayi is the most easily distinguished.It has the largest flowers in this genus, with the corolla measuring about 3 cm long and 2.5 cm diam.at the mouth.The calyx is also the largest within the genus, measuring up to 1.3 cm long and up to 1.2 cm diam.Leenhouts (1962) considered this species part of his Fag raea racemosa in spite of these differences.Utania maingayi also differs from typical specimens of U. racemosa in the following characteristics.The main axis of the inflorescence is clearly seen and not hidden by flowers or flower groups in U. maingayi and the flowers or flower groups are in distinct tiers.The leaves of U. maingayi are typically oblong to lanceolate or obovate, and the secondary veins are sometimes inconspicuous and fading as they approach the leaf margin.In U. racemosa, the main axis of the inflorescence is largely obscured from view by the dense arrangement of flowers or flower groups, the leaves are mostly elliptic-ovate, sometimes lanceolate, and the secondary veins are always prominent on the lower leaf surface, often clearly looping near the margin.

P r o o f s
fruit-bearing part of the infructescence not conspicuously thicker than the proximal part and the peduncle, typically obscured from view by the very closely spaced fruiting tiers.Fruit apex beaked; smooth; when mature to 14-18 mm long, 8-13 mm diam.; the base tightly clasped by the calyx lobes.Seeds usually slightly elongated; 1.5-2 mm long, 0.5-1 mm diam.Fig. 2. Habitat and distribution -Tropical freshwater swamp forest and dryland tropical evergreen lowland forest, in forest understory and fringes, on alluvial soils.Confined to the southern half of the Malay Peninsula, with highly localised populations threatened by habitat changes including agricultural development.We have been able to verify good populations still intact in Pulau Tekong, Pulau Tekong Kechil and Pulau Ubin (including Chek Jawa) (Singapore).Notes -The flowers are fragrant.The plants are frequently infested with red weaver ants (Oecophylla smaragdina Fabricius), as noted in the field in Mawai, Johor (Sugumaran et al. SM 201), and also in Singapore collections (Gwee et al.GAT 339,Lai LJ 157).
Utania nervosa is easily distinguished from U. cuspidata and U. racemosa by its greater number of secondary veins (10-16 pairs in U. nervosa, compared to only 5-7 pairs in U. cuspidata and U. racemosa).In U. nervosa, the inflorescence peduncle is massive, 5-6 mm diam., but more slender in the others (only 2-3 mm diam. in U. cuspidata and U. spicata; 2-3(-4) mm diam. in U. racemosa).It is also much shorter (only 0.8-2 cm long) than in U. cuspidata (11.5-23 cm long).In U. nervosa (and also U. cuspidata and U. ra cemosa), the mature fruits are tapered at both ends (spindleshaped) but in U. spicata they are apically more rounded (somewhat top-shaped).
There are other differences.Utania nervosa has branches on the stem that are stiff and ascending compared to long, limply pendulous branches in mature trees of U. spicata.
Utania nervosa inflorescences have more branching orders, (2-)3-4 orders, whereas U. spicata inflorescences have less, only up to 1-2 orders; consequently the inflorescence in U. nervosa typically has a greater number of closely packed flowers than in the other species.Flower pedicels are much shorter (2-3 mm long) in U. nervosa but longer (7-20 mm long) in U. cuspidata.In U. nervosa, the calyx lobes in dried material are tightly clasping the corolla or fruit base but loosely clasping or spreading in U. spicata.In U. ner vosa, the corolla lobes are much longer and wider (9-10 mm × 7-8 mm) than in U. spicata (3-4 mm × 4-5 mm).
Small tree, c. 2 m tall.Leaves elliptic-ovate to ellipticoblanceolate; (2.5-)5.5-7(-9.3)cm long, (1-)2.5-3(-4.2) cm wide; base cuneate; apex caudate; margin flat; thin coriaceous; glabrous on both surfaces; midrib prominent below, sunken above; secondary veins 3-4 pairs, faint on both sides; tertiary veins inconspicuous; petioles 10-17 mm long, 1-1.5 mm diam.Inflorescence terminal, a many-flowered panicle, 1-2.7 cm long; peduncle c. 1.8 cm long, c. 1 mm diam.; rachis in the distal half of the flowerbearing part of the inflorescence not conspicuously thicker than the proximal part and the peduncle, clearly visible; branch tiers closely spaced (except sometimes the basal two tiers well-spaced, 4-5 mm apart), all branch tiers with only 1 branching order.Flower pedicel 3-4 mm long, 1-1.5 mm diam.; calyx (from the base to the lobe apices) 5-6 mm long, glabrous, calyx cup 3-4 mm diam., calyx lobes erect and tightly clasping the corolla tube, 2-3 mm long, 2-3 mm wide, margins glabrous; corolla broadly infundibular (the mouth more than 3-4 times the diam. of the lower narrowed part of the tube); white; lower subcylindrical part of the corolla tube c. 8 mm long, c. 2 mm diam., upper flared part of the tube slightly inflated, c. 6 mm long, c. 7 mm diam.at the top; corolla lobes broad-obovate to suborbicular, 5-6 mm long, 3-4 mm wide; stamens inserted at the upper portion of the lower narrowed tubular part of the corolla tube or the lowermost portion of the upper flared part of the corolla tube; filaments 6-7 mm long, slightly protruding to 2 mm from the corolla mouth; anthers not seen; style 17-19 mm long, slightly protruding to 3-5 mm from the corolla mouth in the open flower; stigma shallowly 2-lobed, the lobes broadly suborbicular and recurving when receptive (sometimes resembling a somewhat peltate structure c. 1 mm diam.).Infructescence peduncle 1-1.5 cm long, 1-1.5 mm diam.; rachis in the distal half of the fruit-bearing part of the infructescence not conspicuously thicker than the proximal part and the peduncle, clearly visible.Fruit apex beaked; smooth; when mature to 10-14 mm long, 7-9 mm diam.; the base tightly clasped by the calyx lobes.Seeds usually slightly elongated; 1-1.2 mm long, 0.5-1 mm diam.

P r o o f s
Habitat and distribution -Tropical lowland evergreen rainforest, on sandstone-derived and alluvial soils.Endemic to the southern half of the Malay Peninsula, very rare.
Notes - King & Gamble (1908: 609) and Ridley (1923: 420) identified material of this as "Fagraea ligustrina" (not of Blume 1838).Leenhouts (1962) considered this as part of a very variable Fagraea racemosa, which is here reinterpreted (see Key provided in this paper and Utania racemosa below).
Notes -Utania racemosa (previously Fagraea racemosa) has been confused with the related U. volubilis (previously F. volubilis, see following species).As noted by Wong & Sugau (1996), the material of U. volubilis in Wallich's collection in Kew contained both U. volubilis and U. racemo sa, as two separate herbarium sheets with the same number "1600" that have been labelled "F.volubilis Jack".They noted that the sheet marked "1600.E Bencoolen" on its bottom left is to be regarded as the type of F. volubilis Wall.(= U. volubilis), whereas the other sheet marked "1600 Herb.Finl." is F. racemosa (= U. racemosa) and is to be dismissed from the typification of F. volubilis (= U. volubilis).Wong & Sugau (1996) have also pointed out Ridley's earlier comment (Ridley 1894) that some of Jack's specimens distributed by Wallich as from Penang could in fact have originated from Sumatra.They suggested that, as both these species occur in Penang as well as in Sumatra, there could have been some confusion of material during the distribution of Bencoolen (Sumatra) and Penang specimens, or material under "1600" could originally have been a mixed collection.
Utania racemosa does not extend to Borneo or eastwards.Herbarium material that has been confused with this species from Borneo is distinguishable as U. volubilis, as demonstrated in the key provided here.Other taxa from farther east, including New Guinea, are also distinguishable by such characters as the length of the inflorescence, the number and length of inflorescence branches, and their spacing on the rachis, as well as individual calyx and corolla characteristics.However, the proper identification of these other taxa would require careful consideration of the various names that have been previously applied, and their typification, and must wait a future undertaking as these studies are beyond the Sundaland phytogeographical region.
Utania racemosa is itself a morphologically variable species in its floral as well as leaf characters but nonetheless is clearly distinguishable from the other species in the Malay Peninsula.The leaf sizes are generally big, up to 30 cm long and 14-20 cm wide, and the shape is elliptic-ovate to ellipticlanceolate.The typical calyx size is about 4-6 mm long.The internode length between the lowest flowering node (closest to the peduncle) and the following flowering node tends to be variable even within the same plant.All the subsequent internodes are very short so that the inflorescence appears to be very condensed distally.Thus, most of the inflorescence main axis is hidden by the flower clusters and not easily visible.The first internode length, expressed as a percentage of the total inflorescence rachis length measured from fifteen inflorescences on a single plant growing in the University of Malaya's Rimba Ilmu Botanic Garden, showed a range of 11-60%.Thus the within-species variation in some characters may have obscured differences in other characters with various other species.Wong & Sugumaran (2012: 493).-Fagraea volubilis Wall. in Roxb.(Roxburgh 1824: 36); Wong & Sugau (1996: 40).-Type: Sumatra, Bencoolen, sin.dat.(fr), Jack (Wallich, Cat.1600 E) (holo-: K).
tile, hastate; style not to slightly exsert; stigma peltate.Fruit small to medium-sized, ellipsoid to broadly ellipsoid, up to 15 mm in diam.; colour at maturity pale to dark brown; without latex in fruit epidermis or fruit wall; epidermis not separating from pericarp (fruit surface firm and appearing smooth in herbarium specimens).Seeds numerous; placentation axile; polygonal; surface areolate.Distribution and diversity -Indo-China (Cambodia, South Vietnam), Thailand, the Andaman and Nicobar Islands, Malay Peninsula, Sumatra, Java, Borneo, Celebes, Maluku, the Philippines and New Guinea.About fifteen species.Habitat -Lowland forests below 1000 m elevation (including dryland tropical evergreen rainforest and seasonal forests, and periodically inundated tropical freshwater swamp P r o o f s forest), as well as secondary vegetation; rarely in degraded open sites.1.Utania austromalayensis M.Sugumaran, sp.nov.