Chapelieria magna, a new species of Rubiaceae from eastern Madagascar

Kent Kainulainen; Sylvain G. Razafimandimbison

doi:10.3897/phytokeys.44.8513

Research Article

Chapelieria magna, a new species of Rubiaceae from eastern Madagascar

Kent Kainulainen^‡, Sylvain G. Razafimandimbison^§

‡ The Bergius Foundation, Royal Swedish Academy of Sciences and Stockholm University, Stockholm, Sweden

§ Stockholm University, Stockholm, Sweden

Corresponding author: Kent Kainulainen ( kent@bergianska.se )

Academic editor: Lena Struwe

This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Kainulainen K, Razafimandimbison SG (2015) Chapelieria magna, a new species of Rubiaceae from eastern Madagascar. PhytoKeys 44: 89-95. https://doi.org/10.3897/phytokeys.44.8513

Abstract

A new species of Chapelieria was discovered during a recent field trip to the Masoala National Park in eastern Madagascar, and is described here as Chapelieria magna Kainul., sp. nov. This species is readily distinguishable from previously described species of the genus by its quadrangular shoots, triangular-calyptrate stipules, sessile leaves, pubescent styles, and ridged fruits. It also differs in the larger number of ovules and the much larger size of leaves and fruits.

Keywords

Chapelieria , Madagascar, Octotropideae, Rubiaceae

Introduction

Chapelieria A. Rich., is a genus endemic to Madagascar that belongs to tribe Octotropideae (Rubiaceae; subfamily Ixoroideae). The taxonomic history of the genus is complex (Madagascar Catalogue 2014). Chapelieria madagascariensis A. Rich. was originally described by Richard (1830), commemorating Louis Armand Chapelier who had collected the type material in eastern Madagascar. However, the name was first published by De Candolle in September 1830, citing Richard’s (1830) manuscript that was not published until December that same year (Stearn 1957). De Candolle’s (1830) description is essentially identical, but with an added note on the similarity of the plant habit to that of an Apocynaceae. Baillon (1880), considered Chapelieria and Tamatavia Hook.f. as congeneric. Tamatavea melleri had been described by Hooker (1871: pl 1090) just a few years earlier although with some reservation as to its novelty: “I advance this genus as new with some hesitation, because it may prove to be one of the several Madagascarian genera which are so imperfectly or incorrectly characterized in systematic works, that it is impossible to recognize them by their description”. Schumann (1891), included Tamatavia melleri in Chapelieria as C. melleri, and Chevalier (1942) subsequently synonymized the two names.

In a revision of Malagasy Apocynaceae, Pichon (1949) noted that the type material of Chapelieria madagascariensis was mixed and included both Apocynaceae and Rubiaceae material, and consequently he synonymized the name under Carissa edulis Vahl var. septentrionalis Pichon. The Apocynaceae specialists Markgraf (1976), and Leeuwenberg and van Dilst (2001), also considered Chapelieria a synonym of Carissa. Recently, however, Davies and Davis (2014), emended the description of Chapelieria madagascariensis and specified one of the Chapelier specimens as the holotype (a paper to clarify the issue of the typification is in preparation, Davis AP, pers. comm.). They also described two new species of Chapelieria (C. multiflora N.M.J. Davies & A.P. Davis and C. septentrionalis N.M.J. Davies & A.P. Davis), and estimated the total number of species in Madagascar to be about ten.

During a recent field trip to southern Masoala National Park, we collected an unknown Chapelieria and it is here described as a new species. Morphologically, the plant conforms to the characterization of tribe Octotropideae by Tosh et al. (2009), having articulated petiole bases with distinct sutures, paired supra-axillary inflorescences, hermaphroditic flowers with secondary pollen presentation, funnelform corollas with left-contorted aestivation, 2-locular ovaries with axile placentation, pendulous ovules, and striate pattern of the seed coat. Characters that support a placement in Chapelieria as described by Davies and Davis (2014), include the sessile inflorescences, sessile flowers, 5-merous flowers, and seeds with entire endosperm. In contrast, the new species does not have grooved/ridged styles, and further broadens the generic description of Chapelieria (Davies and Davis 2014) by having stipules fused to a cap that cover the apical buds, sessile leaves, simple styles (not club-shaped), and in the larger number of ovules per locule (16 vs. 3–7). Furthermore, the styles of this species are sparsely pubescent, and the fruits are distinctly ribbed. The latter two traits are also be found in the genus Flagenium Baill. Characters that distinguish Flagenium from Chapelieria include the presence of both erect and pendulous ovules, and the absence of articulated petioles (Ruhsam and Davis 2007). Preliminary molecular phylogenetic analyses of both cpDNA and rDNA data support a position of the new species in Chapelieria (Kainulainen et al. unpublished data).

Flower buds of Chapelieria are enclosed by calyptrate bracts (Chevalier 1947), and this is also the case in Chapelieria magna. The conical sheath formed by the fused bracts is split by the expanding flower buds, but the bracts persist as an asymmetric triangular sheath around the inflorescence branches. Lateral buds appear to form continuously, and many buds of varying levels of development are found within the cymose inflorescences. However, because of the congested nature of the inflorescence, branchlets with primordial buds may appear as single bracteolate flowers.

Taxonomy

Chapelieria magna Kainul., sp. nov.

urn:lsid:ipni.org:names:77144550-1

Figures 1, 2

Diagnosis

Differs from previously described species of Chapelieria (C. madagascariensis, C. multiflora, and C. 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 (1^st 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 C. 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 C. 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.

Figure 1.

Chapelieria magna. A Habit and habitat B Flowering branch. Note the apical calyptrate stipules (one leaf removed) C Flower buds, and fruits in longitudinal and transversal sections, on leaf (×1.5) D Fruits E Inflorescence on leaf (×1.5). Photographs by Kent Kainulainen.

Figure 2.

Chapelieria magna. A Leaf B Longitudinal section of corolla. C Stigma D Part of an inflorescence with flower buds and bracts E Longitudinal section of ovary and calyx F Fruit G Seed. Drawings from the holotype: Razafimandimbison et al. 1240, by Kent Kainulainen.

Acknowledgements

We thank Hanta Razafindraibe and the Masoala park guide Séraphin for assistance in the field; Charlotte M. Taylor, Birgitta Bremer, and Khoon Meng Wong for helpful comments on an earlier version of the manuscript, and two anonymous reviewers for comments on this version; the DGF (Direction Générale des Forêts) and MNP (Madagascar National Parks) in Madagascar for issuing collecting permits; the Missouri Botanical Garden, Madagascar Program for logistical support; the Parc Botanique et Zoologique de Tsimbazaza and Missouri Botanical Garden, Madagascar Program (Faranirina Lantoarisoa) for arranging collecting permits. Travel grants for the field trip were provided by the Royal Swedish Academy of Sciences.

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