Chapelieria magna Kainul., 2015

Kainulainen, Kent & Razafimandimbison, Sylvain G., 2015, Chapelieria magna, a new species of Rubiaceae from eastern Madagascar, PhytoKeys 44, pp. 89-95 : 91-93

Chapelieria magna Kainul. sp. nov. Figures 1, 2

Diagnosis.

Differs from previously described species of Chapelieria ( Chapelieria madagascariensis , Chapelieria multiflora , and Chapelieria septentrionalis ) by its quadrangular shoots; triangular-calyptrate stipules; sessile leaves (vs. petiole 5-11 mm); simple, terete, sparsely pubescent styles (vs. club-shaped, grooved/ridged, glabrous styles); ovule number (ca. 16 vs. 3-7 per locule); distinctly ridged fruits (vs. ± smooth fruits); and the much larger size of leaves (up to 42 × 12.2 cm vs. <16.6 × 7.8 cm), and fruits (up to 45 × 20 mm vs. <13 × 7.0 mm).

Type.

MADAGASCAR. Toamasina Province: Analanjirofo Region, Maroantsetra District, Masoala National Park, 15°41.910'S; 49°57.815'E, 115 m altitude, 15 January 2013 (fl.), S.G. Razafimandimbison et al. 1240 (holotype S!, isotype, TAN!).

Description.

Treelet, to 4 m tall, all vegetative parts glabrous; with decussate, horizontal branches; branchlets quadrangular, 4.0-7.0 mm in diameter, bark drying brown. Stipules ca. 25-30 mm long, initially calyptrate and covering the apical bud, subsequently interpetiolar, triangular, with raised median line and apiculate apex; persistent. Leaves: sessile, narrowly obovate, ca. 39.0-42.0 × 10.5-12.2 cm; bases acute-auriculate; apices acute; adaxial surface: green when fresh, drying pale brownish-gray, smooth, secondary veins brochidodromus, obvious, curved, 15-20 pairs; midribs prominent, pale green when fresh, ± the same colour of the leaf when dry; abaxial surface: pale green when fresh, pale brown when dry, veins reddish-brown. Inflorescences ± sessile, many-flowered (although only 1-few flowers may be mature at any given time); bracts initially calyptrate and covering the flower buds, subsequently splitting unequally to asymmetric, ± triangular sheaths, ca. 18 × 21 mm (1st order bracts), pale green-bright reddish pink, adaxially glabrous, abaxially densely strigose (hairs ca. 0.9 mm), bracteoles reduced; Flowers: hypanthium narrowly urceolate, ca. 6.7 × 2.0 mm; calyces greenish white-bright reddish pink; calyx tubes 3.0-5.0 mm long, externally glabrous, but with hairs (ca. 0.5-1.0 mm long) and colleters on the lower inner surface; calyx lobes ca. 7.5 × 1.3 mm, narrowly triangular, with ciliolate margins (hairs ca. 0.5-2.5 mm); corollas white, funnelform, ± curved; corolla tubes ca. 15 mm long, externally and internally glabrous; corolla lobes ca. 10 × 4.6 mm long, acute, recurved at anthesis; stamens: sessile, attached ca. 3 mm below corolla sinus; anthers white, ca. 7.9 × 0.8 mm, linear, medifixed, exserted for ca. 0.5-1.0 mm; styles simple, ca. 16.5 mm long, sparsely pubescent (hairs ca. 0.5 mm long); stigmas shortly bifid (lobes ca. 0.5 mm long); exserted for ca. 0.5-1.0 mm; ovary ellipsoid, 2-locular, ovules arranged in two series, pendulous, ca. 16 ovules per locule; Fruits: mature fruits red, ca. 36-45 × 14-20 mm, glabrous, fleshy-indehiscent, fusiform, and apically elongated, with distinctive longitudinal grooves/ridges; calyx lobes persistent. Seeds: maturing at ± same rate, ca. 4.8-6.8 × 4.0-6.0 mm, compressed and angular.

Distribution and habitat.

Chapelieria magna is only known from the type collection, made from a small stand of understory treelets in the rainforest of southern Masoala National Park. Notably, Chapelieria madagascariensis also occurs in this area. Although previously only known from the (eastern) Masoala peninsula by a collection made in 1951 (A. Tata 3404-RN; Davies and Davis 2014), we collected a specimen 4.7 km south of the Chapelieria magna locality in the nearby Tampolo littoral forest (Razafimandimbison et al. 1217A; S, TAN). However, whereas Chapelieria madagascariensis was found on sandy soil (cf. Davies and Davis 2014), the habitat of Chapelieria magna was on lateritic soil.

Phenology.

Both flowers and fruits were found when we collected Chapelieria magna in mid-January. This is during the rainy season in Madagascar.