Danais antilahimenae C. M. Taylor, 2013

Taylor, Charlotte M. & Rogers, Zachary S., 2013, Six new species of Danais Vent. (Rubiaceae, Danaideae) from Madagascar, Candollea 68 (1), pp. 167-180 : 169-171

1. Danais antilahimenae C. M. Taylor , spec. nova

( Fig. 1 A-C).

Typus: MADAGASCAR. Prov. Toamasina: Analanjirofo Region, Ambinanihely, Camp I, Befontsimanta , 15°29’53”S 49°22’56”E, 919 m, 21.XI.2003, fl., Antilahimena 2340 (holo-: MO-6306540 ! ; iso-: K, P, SUNIV!, TAN).

Haec species a congeneris stipulis bilobis grandibus marginibus plerumque serratis, foliis grandibus atque inflorescentia grandi axibus prolongatis spiciformibus distinguitur.

Woody lianas or climbing shrubs, climbing to 8 m high; stems puberulous, quadrangular. Leaves opposite; blades elliptic, ovate, or obovate, 12-24 × 6-9.5 cm, at base acute to cuneate, at apex acuminate with tips 3-10 mm, drying papery to chartaceous, adaxially glabrous, abaxially glabrous to puberulous on lamina and puberulous to strigillose or strigose on principal veins, with margins plane; secondary veins 12 to 18 pairs, looping to interconnect with each other near margins, adaxially costa and secondary veins plane to prominulous and tertiary venation prominulous and rather loosely reticulated, abaxially costa and secondary veins prominent and intersecondary and tertiary venation prominulous. Petioles 10-30 mm, puberulous to glabrescent. Stipules interpetiolar, persistent at least on distalmost 3 or 4 nodes, ovate to triangular or elliptic, 7-13 mm, abaxially puberulous to glabrescent, at apex obtuse to acute and shortly 2-lobed, margins entire to usually serrate or sparsely shortly laciniate. Inflorescences terminal and in axils of uppermost leaves, paniculate, pyramidal in outline, 15-38 × 12-26 cm (including peduncles), multiflowered (ca. 60 to 200 flowers), branched to 2 to 3 orders, with principal axes spiciform, with axes puberulous, with basalmost secondary axes often subtended by ovate foliaceous bracts (or reduced leaves) 5.5-8.5 × 4-6.5 cm on stipes (or petioles) 0.3- 1.5 cm; other bracts linear to triangular, 0.3-3 mm. Flowers in dichasial groups of 2 to 5 with terminal flower sessile and others subsessile to pedicellate on pedicels up to 1 mm, with floral biology (i.e., distyly vs. monomorphy) unknown; hypanthium (i.e., ovary portion) ellipsoid-obconic, ca. 0.8 mm, densely puberulous. Calyx limb divided nearly to base, densely puberulous, lobes 5, narrowly triangular, ca. 1 mm, acute. Corolla slenderly funnelform to salverform, purple, externally glabrous, internally sparsely pilose in throat and upper 2/3 of tube, tube 10-10.5 mm, ca. 1 mm diam. at base, ca. 1.5 mm diam. at throat, at base fenestrate with 5 slits, each slit 1.5- 2 mm, lobes 5, narrowly triangular, ca. 3 mm, acute and shortly thickened at apex; stamens 5, inserted in throat, anthers 1.2- 2 mm, purple, exserted on filaments ca. 4 mm. Stigmas 2, linear, ca. 2 mm, included and positioned above middle of corolla tube, style ca. 5 mm. Capsules subglobose to somewhat oblate, 3 × 3-3.2 mm, stiffly chartaceous, densely puberulous, dehiscent through flattened to broadly triangular beak portion (i.e., top part inside calyx limb), often also splitting from apex for 1/3-1/2 of body. Seeds irregular in shape but generally elliptic to rectangular, 0.3-0.8 mm, flattened, with circumferential wing shortly laciniate and usually elongated on one side.

Names. – The scientific name of this robust handsome species is created here to honor Mr. Patrice Antilahimena, collector of the type specimen and one of the Missouri Botanical Garden’s resident field botanists. Mr. Antilahimena has extensively documented Madagascar’s flora with excellent specimens collected during numerous explorations made throughout the island. No vernacular name has been noted in the information available.

Habitat and distribution. – This species is documented from humid forests at 600-1125 m in eastern Madagascar, in northern Toamasina Province (Analanjirofo Region) in the area of the Masoala Peninsula and Baie d’Antongil ( Fig. 2 , humid bioclimatic zone). This species is known from a limited geographic distribution; see MADAGASCAR CATALOGUE (2013) for detailed distribution mapping.

Conservation status. – Danais antilahimenae has an EOO of 134 km 2, which meets the criterion for Endangered; an AOO <500 km 2, which also meets the criterion for Endangered; and three subpopulations. The species is known from three localities, only one of which falls inside the boundaries of a currently protected area (Masoala National Park). The habitat of this species is already significantly fragmented and expected to diminish further in quality. Danais antilahimenae is assigned a preliminary conservation status of Endangered due to its limited distribution and threatened habitat [EN B1ab(i,ii,iii,iv)+2ab(i,ii,iii,iv)].

Notes on morphology and similar species. – This new species is characterized by its relatively large leaves (for Danais ), its rather large stipules with shortly laciniate to usually serrate margins, its relatively very large inflorescences (for Danais ) with the secondary axes prolonged and spiciform, its medium-sized flowers with purple corollas, and its small fruits. The stipules of this species are unusual in Danais , and similar only to those of D. rakotovaoi ; see the discussion of that second species below for the distinctions between these. Only one flowering collection has been seen, with flowers that resemble the short-styled form of distylous species of Danais . The presence of the foliaceous bracts or reduced leaves at the base of the inflorescences is consistent in the specimens studied. The overall inflorescence arrangement of D. antilahimenae (apart from the narrowly spiciform secondary axes) and its small fruits are similar to the species that PUFF & BUCHNER (1994) included in their informal “ Danais microcarpa group”. However the species included in that group are all characterized by white to yellow, shorter corollas, with the tubes 1-5.5 mm long, whereas the flowers of D. antilahimena are more similar to those of another Malagasy species, D. nigra Homolle , which has black to dark purple corollas and well developed corolla tubes. Danais nigra differs from D. antilahimenae in its short (ca. 1 mm long) triangular stipules, its regularly cymose inflorescence axes, and its longer corollas (tubes 11-20 mm long).

Paratypi. – MADAGASCAR. Prov. Toamasina: Analanjirofo, Maroantsetra, Antsirabesahatany, Anjiahley , 15°26’30”S 49°32’19”E, 600 m, 27.XII.2002, fr., Antilahimena, Pascal & Ramaroson 1627 ( MO!) ; Masoala National Park , E slope of Ambohitsitondroinan’ Mahalevona, ESE of village of Mahalevona, 15°26’00”S 49°57’34”E, 1125 m, 23.II.2003, fr., Lowry, Schatz & Be 6097 ( K, MO!, P, TAN).

Figures

Fig. 1. – Danais antilahimenae C. M. Taylor. A. Flowering branch; B. Portion of inflorescence, with young fruits; C. Flower at anthesis. – Danais masoalana C. M. Taylor.D. Flowering branch; E. Stem node with stipule, bases of two petioles, and bases of two axillary peduncles; F. Flower at anthesis; G. Flower at anthesis, partially dissected. [A, B: Antilahimena & al. 1627, MO; C: Antilahimena 2340, MO; D-G: based on Hoffmann & al. 36, MO] [Drawing: C. M. Taylor]

Fig. 2. – Distribution of Danais antilahimenae C. M. Taylor (triangles) and Danais rakotovaoi C. M. Taylor (stars), mapped over the outlines of the five simplified bioclimatic zones of Madagascar of SCHTZ (2000, following CORNET, 1974).