Solanum truncicola Bitter, Bot. Jahrb. Syst. 54: 435. 1917, as "truncicolum"

Knapp, Sandra & Vorontsova, Maria S., 2016, A revision of the " African Non-Spiny " Clade of Solanum L. (Solanum sections Afrosolanum Bitter, Benderianum Bitter, Lemurisolanum Bitter, Lyciosolanum Bitter, Macronesiotes Bitter, and Quadrangulare Bitter: Solanaceae), PhytoKeys 66, pp. 1-142 : 101-105

Solanum truncicola Bitter, Bot. Jahrb. Syst. 54: 435. 1917, as "truncicolum" Figures 1F , 30

Type.

Madagascar. Fianarantsoa: “Süd-Betsiléo, Wald von Ankafina", Mar 1881, J.M. Hildebrandt 3954 (lectotype designated here: JE [JE00004288]; isolectotypes: B [destroyed], BM [BM000797934], G [G00442590], K [K000414186], M [M0105578], W [W18890032421]) .

Description.

Epiphytic shrub or liana, 1-1.5 m tall. Stems terete, ribbed or slightly winged, glabrous, the short shoots on larger plants occasionally minutely pubescent with simple uniseriate trichomes ca. 0.1 mm long, glabrescent; new growth glabrous or minutely puberulent. Bark of older stems smooth or longitudinally ridged, light grey to brown, glabrous. Sympodial units plurifoliate, the leaves not geminate, evenly distributed along young branches or clustered on short shoots. Leaves simple, 1.5-8(13) cm long, 0.5-3 cm wide, lanceolate to elliptic or oblong, coriaceous to thick chartaceous, drying concolorous, dull green to reddish brown, glabrous on both surfaces or the abaxial midvein and margins sometimes sparsely pubescent with simple uniseriate trichomes ca. 0.1 mm long; major veins 4-5 faint pairs at ca. 60° to the midvein, the finer venation not visible; base cuneate to attenuate, occasionally long attenuate with lamina extending to the base of the petiole; margins entire, slightly revolute in herbarium specimens, occasionally minutely pubescent with dendritic or simple trichomes like those on the midvein; apex acute; petiole 0.1-0.5 cm long, thick, drying ridged, glabrous or with a few simple uniseriate trichomes like those of the midvein abaxially. Inflorescences terminal at the apex of short slender lateral branches, appearing axillary when terminal shoot is condensed, 2-4 cm long, unbranched, with 1-2 flowers, glabrous; peduncle absent; pedicels 1.3-2 cm long, apically dilated, ridged in dry material, usually glabrous, sometimes with sparse erect simple multicellular hairs up to 0.15 mm long, articulated 0-1 mm from base; pedicel scars indistinct. Buds oblong, the corolla immediately exserted from the calyx tube in bud long before anthesis, exceeding the calyx lobes. Flowers 5-merous, apparently all perfect. Calyx tube ca. 1 mm long, openly cup-shaped, the lobes 0.4-1.1 cm long, 1-1.5 mm wide at base, linear to ovate, obtuse to acute at the tips, foliaceous, glabrous or with occasional simple trichomes on the margins. Corolla 1.7-3 cm in diameter, white to pale or dark purple, stellate, lobed almost to base, the lobes 8-15 mm long, 2-4 mm wide, narrowly elliptic, occasionally expanded near the base with what look like wings, often aristate with a subulate appendage ca. 1 mm long arising from the adaxial surface of the lobe just below the tip, glabrous adaxially, with enlarged papillose cells and unicellular to simple uniseriate trichomes on the tips and margins. Stamens equal; filament tube 0.5-1 mm; free portion of the filaments ca. 1.5 mm long, glabrous; anthers 5-6 mm long, ca. 1.5 mm wide, ellipsoid, loosely or tightly connivent, poricidal at the tips, the pores slightly smaller than anther apices, not lengthening with age, the surface dark and papillose adaxially. Ovary conical, glabrous; style 6-9 mm long, protruding 1-2.5 mm beyond the anthers, curved, glabrous; stigma clavate, the surface smooth. Fruit an ovoid berry, ca. 1.1 cm long, ca. 0.6 cm in diameter (immature), apically pointed, the pericarp thin, glabrous; fruiting pedicels ca. 3 cm long, ca. 0.8 mm in diameter at base, pendent or spreading, ridged; fruiting calyx lobes up to 8 mm long, accrescent and as long as or longer than developing fruit. Seeds not known.

Distribution

(Figure 31 ). Endemic to the east-central region of Madagascar in Antananarivo, Fianarantsoa, and Toamasina provinces.

Ecology and habitat.

Humid and subhumid montane forest; (600-)1000-2000 m elevation.

Common names and uses.

Madagascar. hendramena, farafandoha ( D’Arcy and Rakotozafy 1994, as Solanum humblotii ).

Preliminary conservation status

( IUCN 2014). Vulnerable (VU B1a, biii). EOO 19,845 km2 (VU), AOO 56 km2 (EN). Although Solanum truncicola has been been consistently but sparsely recorded over a coherent stretch of the eastern Malagasy rainforest from Toamasina in the northernmost part of its distribution range to the Ambalavao area in the southernmost part, the highly fragmented nature of these eastern forest habitats gives cause for conservation concern.

Discussion.

Solanum truncicola is a rare and unusual montane forest shrub or epiphyte. It is easily identifiable by its coriaceous leaves and long, almost linear calyx lobes which are divided to the base before the corolla begins to expand (Fig. 30A ). The length of the calyx lobes (0.4-1.1 cm) in combination with the deeply stellate corollas with narrow lobes makes its flowers appear to be two overlapping stars (see Fig. 1F ). Petioles of Solanum truncicola are the shortest of all Madagascar Solanum species (1-5 mm), usually less than 1/8 of the total leaf length. The flowers can reach 3 cm in diameter, and anthers to 6 mm in length.

Misidentification of Solanum truncicola is not likely, even though its height, internode length, and leaf size vary spectacularly across its distribution range: leaves of the type specimen are ca. 1.5 cm long, while leaves on other collections reach 13 cm. Some large leaved forms become reminiscent of Solanum myrsinoides in habit and can be distin guished from Solanum myrsinoides by their inflorescences of 1-2 (versus 2-6) flowers and calyx lobes 0.4-1.1 cm (versus less than 0.1 cm) long.

Bitter (1917) correctly described Solanum truncicola as distinct from Solanum humblotii . Solanum truncicola can be distinguished from Solanum humblotii by its petioles 0.1-0.5 cm (versus 0.6-1 cm) long, acute (versus acuminate) leaves, glabrous (versus pubescent) young stems, narrowly ovate to obovate (versus deltate to acuminate) calyx lobes, and a different overall appearance. D’Arcy and Rakotozafy (1994) included Solanum truncicola as a synonym of Solanum humblotii , perhaps because Bitter’s key only highlighted the more superficial indumentum and size differences between the two species, and the type collections were not carefully consulted. During the years that followed D’Arcy and Rakotozafy’s treatment, many specimens of Solanum truncicola were determined as Solanum humblotii ; this has caused considerable confusion in herbaria. The two species occur in similar wet forest habitats but are allopatric with Solanum truncicola having a more southerly distribution and at higher elevations than Solanum humblotii .

Although the original spelling of the epithet is " truncicolum " ( Bitter 1917) the word element - cola should be treated as a noun in apposition and this is a correctable error to truncicola (Article 23.5, McNeill et al. 2012).

Label details on Malcomber et al. 1353 (MO) record the pedicel and calyx as dark purple. The anthers on at least one flower of Malcomber et al. 1353 are clearly connate but distinctly free on other flowers of the same specimen and on other collections.

Bitter (1917) cited three herbaria in the protologue - G-Boiss., B and “Haussknecht” (now held in JE). We have selected the duplicate at JE as the lectotype because it bears an annotation label in Bitter’s handwriting and is a larger specimen with more flowers than that at G.

Selected specimens examined.

Madagascar. Fianarantsoa: Ivohibe, Andringitra, Andringitra , camp IV, ca. 38 km S of Ambalavao, Andringitra reserve on ridge above headwaters of Sahavatoy river , Dec 1993, Lewis et al. 1083 (P); Ifanadiana, Parc National de Ranomafana , S of Namorona river, parcelle III, trail to Maharira , C. 5 km N of Maharira, 1 Feb 1992, Malcomber & Rakoto 1353 (MO, P, TAN); Ambositra , between Ambositra and Fianarantsoa, 16 Mar 2005, Phillipson et al. 5785 (MO); Ambalavao , Andrisoa, district Ambalavao , 16 Feb 1954, Rakoto & de la Croix 6481 (MO); Andringitra RNI, District d’Ambalavao, Canton de Sendrisoa , 13 Jan 1958, Réserves Naturelles Madagascar 9918 - RN (MO, P); Ranomafana National Park , parcelle 3, S of National Road 25 at 7 km W of Ranomafana, Talatakely trail system, trail AA 0 m [beginning of trail], 18 Mar 1993, Turk et al. 341 (NY, TAN) . Toamasina: Atsinanana, District Brickaville, Commune Maroseranana , Fokotany Ambodilendemy , Ankerana , 26 Mar 2011, Antilahimena et al. 7846 (MO); Rombevavy, Rahobevava, 11 Mar 1951, Cours 4275 (MO, P, TAN); Aloatra-Mangoro, forêt de Perinet, au Nord à 7 km de Perinet vers Tamatave, 28 Feb 1971, Cremers 1481-2 (TAN); Moramanga, Andasibe, Andasibe (Perinet), N of road from Antanarivo to Tametave, NW of Izouard graphite mine on road to col de la Mantady, 1987, Lowry & Schatz 4286 (MO, P, TAN); Chutes de la Mort, route Anosibe-Moramanga, 11 Oct 1960, Peltier & Peltier 2676 (P); Aloatra- Mangoro, Corridor Forestier Analamay Mantadia, 24 Apr 2012, Rasoazanany & Ratolojanahary Tafita 93 (MO, P, TAN); Alaotra Mangoro, Lakato, forest E of Manasamena village, along the Ankandrabe trail, 2 Jun 2007, Randrianasolo et al. 1163 (NY) .

Figures

Figure 1. Flowers of species in the ANS clade. A Solanum africanum Mill. (South Africa, Rebelo s. n. - no herbarium voucher) B Solanum imamense Dunal (Madagascar, Rakotavao 5128) C Solanum madagascariense Dunal (Madagascar, Vorontsova et al. 498) D Solanum sambiranense D'Arcy & Rakot. (Madagascar, Randrianasolo 580) E Solanum terminale Forssk. (Kenya, Vorontsova et al. 93) F Solanum truncicola Bitter (Madagascar, Antilahimena et al. 7846). Photo credits: A Tony Rebelo; B Charles Rakotavao; C, E Maria Vorontsova; D Richard Randrianasolo; E Patrice Antilahimena.

Figure 30. Solanum truncicola Bitter. A Flowering branch B Open flower C Fruiting branch D Stem showing minute simple pubescence E Simple trichome F Mature (?) berry. (Based on: A Malcomber et al. 1353; B Philipson et al. 5875 drawn from photographs; C-F Randrianasolo et al. 1163). Scale bar: A, C = 3 cm; B = 1.5 cm; D, F = 7 mm; E = 0.3 mm. Drawn by Lucy T. Smith.

Figure 31. Distribution of Solanum truncicola Bitter.