Wetschnig, Knirsch & Martínez-Azorín & Pfosser & Wetschnig, 2015

Knirsch, Walter, Martínez-Azorín, Mario, Pfosser, Martin & Wetschnig, Wolfgang, 2015, The reinstatement and rediagnosis of the madagascan genus Rhodocodon (Asparagaceae, Scilloideae), with validation and remarks on H. Perrier’s taxa, Phytotaxa 195 (2), pp. 101-134 : 127-129

12. Rhodocodon rotundus [H.Perrier ex] Knirsch, Mart.-Azorín & Wetschnig sp. nov.

≡ Rhodocodon rotundus Perrier de la Bâthie (1938: 120) , nom. inval.

Illustrations:—fig. XVI (7 ‒ 8) in Perrier de la Bâthie (1938: 121).

Type:— MADAGASCAR.Versant W de l’Isalo, grès, 400 m, October 1924, Perrier 16583 (holotype P 00573467!, Fig. 23 )

Description:—Deciduous bulbous plant, 30 ‒ 60 cm high. Bulb oblate, proliferous, 4 ‒ 6 × 5 ‒ 9 cm; roots white, branching. Leaves 2 ‒ 5 per bulb, absent at flowering time, oblanceolate, 15 ‒ 45 × 2.5 ‒ 5 cm, green, glabrous, slightly curved, with entire, reddish margin. Inflorescence an erect, lax, many-flowered raceme; peduncle 7 ‒ 25 cm long, rigid, green, glabrous; raceme 15 ‒ 30 cm long, with 15 ‒ 35 flowers; pedicels slender, spreading to subpatent, curved downwards at the apex, 20 ‒ 28 mm long, when fruiting up to 35 mm; lowermost bracts subpetiolate, very narrow, lanceolate-linear, 5 ‒ 8 mm long, curved outwards, the base with three nerves, with a thick conic spur 1.5 ‒ 2 mm long; bracteoles present; flowers nodding, greenish brown with purple flush along the suture of the tepals. Perigone urceolate or subglobose, 7 ‒ 7.5 × 7 ‒ 8 mm, tepals connate for most of their length, slightly contracted at the apex, with deltoid or subacute, reflexed lobes, ca. 1 mm long. Stamens 6, filaments adnate to the perigone tube and arising from its basal third; free portion of filaments convergent to the ovary, subulate, ca. 1 ‒ 1.5 mm long; anthers yellow, oval, 1.3 × 1 mm, obtuse and slightly apiculate, the point of insertion at the inferior quarter, dehiscing for their whole length. Ovary subconical, with the widest part at the base, green, 2.5 ‒ 3 × 2 ‒ 2.3 mm, attenuate at the apex, with 7 ‒ 8 ovules per locule; style white, elongate, thickened, cylindrical, ca. 4 ‒ 4.5 mm long; stigma punctiform. Capsule conical, trigonous in transversal section, dark green, 1 ‒ 1.2 × 1 ‒ 1.2 cm. Seeds hemiellipsoidal, L-H-W: 4.1 ‒ 2.4 ‒ 2.6 mm, black, glossy, with a light brown distinct raphe. Fig. 24 .

Diagnosis:— Rhodocodon rotundus resembles R. campanulatus , but the former differs by the erect, less flowered and shorter inflorescence, the bigger flowers, the shorter pedicels, the longer bracts, and the presence of bracteoles.

Habitat:— Rhodocodon rotundus grows in sandy, humus-rich soil in relict dry deciduous forests at about 700 ‒ 800 m of elevation. The landscape is mostly covered by dense or open grassland, with most of the natural vegetation still intact. The Horombe Plateau has seasonally humid climate. The highest temperatures occur in January (mean of 24°C), and the lowest in June–July (mean of 10 ‒ 11°C). The highest precipitation occurs in February (mean of 185 mm), and the lowest from June to August (mean of 5 ‒ 10 mm).

Biology:—Flowering and fruiting time: June to November.

Distribution:— Madagascar. Province Fianarantsoa: region Ihorombe, near Ihosy, road to Sakalalina.

Selected material studied:— MADAGASCAR. Province Fianarantsoa: district Horombe , 771 m, February 2014, W. Knirsch, A. Sieder & J. Andriantiana 6665 ( GZU!) ; Ouest: terrains découverts et rocailleux, près Ihosy , dans le basin du Mangoky, 600 m, July 1911, Perrier 10966 (P 00573468!) ; sables trias, Mangoky, près Beroroho, Perrier 12868 (P 01848489!).

Figures

FIGURE 23. Holotype of Rhodocodon rotundus H.Perrier ex Knirsch, Mart.-Azorín & Wetschnig: Perrier 16583 (P 00573467!).

FIGURE 24. Flower morphology of Rhodocodon rotundus H.Perrier ex Knirsch, Mart.-Azorín & Wetschnig (corresponding to WW 2407!). Lateral view (left), dissection in lateral view (center) and apical view (right). Scale bar 1 mm.