Neonauclea connicalycina Ordas, Taradji, Valdez & Alejandro, 2016

Ordas, Jorge Anton D., Taradji, Ar-Rauf J., Valdez Jr, Marcos B., Banag, Cecilia I. & Alejandro, Grecebio Jonathan D., 2016, Neonauclea connicalycina: a new myrmecophytic species of Naucleeae (Rubiaceae) from Cebu, Philippines, Phytotaxa 273 (2), pp. 127-132 : 128-131

Neonauclea connicalycina Ordas, Taradji, Valdez & Alejandro , sp. nov. ( Figs. 1 , 2 )

Neonauclea connicalycina is distinguished from N. formicaria by its broadly acuminate leaf apices; smaller flowering heads of 40–42 mm; fusiform apical portions of the calyx lobes; longer and sharply pyramidal calyx summits that are brown when dry; calyx lobes that are connate for 1–2 mm and fall off together in a unit; smaller and slender corollas.

Type:— PHILIPPINES. Cebu: Municipality of Carmen, Barangay Hagnaya, 11º 08.41’N, 123º 94.98 E, 3 August 2015, Valdez & Taradji 14c-610 (holotype PNH 255657, isotype USTH 12540).

Medium-sized trees up to 4–6 m high; wood reddish-brown to gray; ultimate branches slender with 7.5–8 × 0.5–0.7 cm long myrmedomes, terminal vegetative bud spathulate-ovate, flattened, rarely slightly keeled. Stipules 15–17 × 11–12 mm, ovate, apex acute to obtuse, glabrous, not persistent. Leaves with petioles stout, 1.5–2.5 cm long, glabrous; leaf blade broadly ovate to elliptic, 15–24 × 8.5–18 cm, broadly acuminate or sometimes acute at apex, cordate to subcordate or sometimes oblique at base, glabrous on both sides, coriaceous, lateral nerves 7–10 pairs. Inflorescence terminal, flowering heads 1–3, floral axis up to 6 cm long; 19–20 mm in diameter of mature flowering heads across persistent part of the calyces, 40–42 mm across corollas; receptacle glabrous, interfloral bracteoles absent. Flower 5- merous; hypanthium 1–1.5 mm long, glabrous. Calyx: persistent part ca. 2 mm long, outside densely pubescent, inside densely sericeous, calyx lobe shafts flattened, 4–5 mm long, densely pubescent with 3–4 vertical line thickenings, shafts always mutually connate at base for 1–2 mm breaking together in units of 4 to 5 lobes, apical portion 3–3.5 mm long, elongate fusiform to turbinate, lower part 1–1.5 mm long, densely pubescent, summit 1–1.5 mm long, sharply pyramidal, longitudinally ridged, dark orange but pallid brown when dried, pubescent. Corolla 13–15 × 3 mm, infundibular, white but tinged with purple on lobes, corolla tube glabrous on lower half, puberulent on upper half on both sides, lobes 1.5–2 mm long, ovate, puberulent on abaxial side with marginal hair; anthers 1.8–2 mm long; style exserted for 9–10 mm long. Fruiting heads with 25–27 mm in diam., fruitlets 5–7 mm in diam., top of adjacent fruitlets cling mutually together and appearing as a pseudosyncarp. Seeds elliptic, 0.6–0.8 mm in diam., 3.5–4 mm across the wings; wings linear, 1–1.5 mm long.

Etymology:— The specific epithet of this new species is based on the calyx lobes that are connate at the bases of the shafts, and detach together when the corollas mature.

Distribution and Habitat:— This new species is currently known only from its type locality. Similarly to most Neonauclea species occurring in the Philippines, Neonauclea connicalycina thrives in lowland secondary and open forests along trails and clearings at elevations of 50– 140 m.

Phenology:— Neonauclea connicalycina was observed flowering and fruiting on August. Discussion:— Neonauclea connicalycina shares similar features with the allied species N. formicaria , in its myrmedomes, widely elliptic coriaceous leaves, ovate and glabrous stipules, absence of interfloral bracteoles, glabrous receptacles and hypanthia, and white puberulent infundibular corollas. However, N. connicalycina differs from N. formicaria by its smaller flowering heads, calyx shafts that are connate at the base for 1–2, fusiform apical portion of the calyx lobes, sharply pyramidal calyx summits that are brown when dried, and smaller and more slender white corollas tinged with purple on the lobes. Table 1 provides a summary of the morphological differences between N. connicalycina and N. formicaria .

Myrmecophytism in Neonauclea has been previously recorded in two species from the Philippines, N. formicaria and N. pseudocalycina Ridsdale (1989: 204) . Thus N. connicalycina is the third myrmecophytic species in the Philippine archipelago. As noted by Razafimandimbison et al. (2005), myrmecophytic Neonauclea from the Philippines are found only in the Visayas and Mindanao regions. Consistent association with Neonauclea species has been observed in the ant genera Cladomyrma Wheeler (1920: 53) and Crematogaster Lund (1831: 132) ( Maschwitz & Fiala 1995, Agosti et al. 1999). Ant samples were not collected during the fieldwork, but it is speculated that N. connicalycina is colonized by Crematogaster ants, because Cladomyrma is absent in the Philippines.

Figures

FIGURE 1. Neonauclea connicalycina live morphology. A. Flowering and fruiting heads. B. Immature flowering heads. C. Terminal vegetative bud enclosed by adpressed stipules. Photos taken by A.J. Taradji.

FIGURE 2. Neonauclea connicalycina A. Flowering and fruiting branch. B. Branch with myrmedome. C. Calyx lobes:A-apical portion; Su-summit; Lp-lower part; S-shaft. D. Flower, right-opened flower with persistent calyx. E. Fruitlet, right-opened fruitlet with seeds. F. Fruitlet, right- opened fruitlet with seeds. From Valdez & Taradji 14c-610 (USTH 12540). Drawn by Propa Joy Santor.