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 : 108-110

2. Rhodocodon calcicola Knirsch, Mart. -Azorín & Wetschnig sp. nov.

≡ Rhodocodon calcicola Perrier de la Bâthie (1938: 115) , ‘calcicolus’, nom. inval.

Illustrations:—fig. XVI (10) in Perrier de la Bâthie (1938: 121).

Type:— MADAGASCAR. Province Mahajanga, few kilometers north of Mahajanga, 60 m elevation, bulbs collected by W. Knirsch, A. Sieder & J. Andriantiana num. 6293 (holotype GZU 000322310!, Fig. 4 ). The holotype material was cultivated in Austria, Steiermark, Graz, Botanical Garden of the Institute of Plant Sciences of the University of Graz, collected and pressed on a single date (30 April 2014) by W. Knirsch, M. Martínez-Azorín & W. Wetschnig .

Description:—Deciduous bulbous plant, 10 ‒ 30 cm high. Bulb subglobose, 2 ‒ 3 × 2 ‒ 3 cm; roots white, branched. Leaves 5 ‒ 8 per bulb, synanthous, oblanceolate, acute, 3 ‒ 5 × 0.8 ‒ 1 cm at flowering time, later reaching 14 ‒ 25 × 1.8 ‒ 2 cm, green, glabrous, smooth, with a slight keel on the abaxial side. Inflorescence erect; peduncle 12–18 cm long, glabrous, smooth; raceme 15 ‒ 25 cm long with 15 ‒ 35 flowers; pedicels 10–13 mm long; lowermost bracts subpetiolate, membranous, acute, ca. 2 × 0.3 mm, with an acute spur 0.2 mm long; bracteoles absent; flowers white, nodding. Perigone urceolate-turbinate, ca. 4 × 4 mm, connate for most of their length, the widest part of the flower at the proximal third or at the middle, slightly contracted at the apex, with obtuse, very short, slightly reflexed, green lobes (0.5 × 0.25 mm), the tube being pure white. Stamens 6; filaments shortly adnate to the perigone tube and arising from its basal portion; free portion of filaments ca. 1.5 mm long, thickened and attenuated at the apex, incurved and approaching the base of the style, the distal 3 quarters papillate and keeled; anthers yellow, oblong, ca. 0.7 mm long, sagittate, acute, dehiscing for their whole length. Ovary cylindrical, subglobose to conical, inconspicuously trigonous at the top, ca. 2 × 2 mm, with 2 upright ovules per locule, filling the lower half of the cavity; style ca. 2 mm long, thinning from base to top; stigma punctiform. Capsule subglobose, ca. 5 × 5 mm, often with 1 or 2 less developed carpels. Seeds hemiellipsoidal, L-H-W: 3.1 ‒ 2 ‒ 2 mm, black, slightly glossy, with a distinct light brown raphe. Fig. 5 .

Diagnosis:— Rhodocodon calcicola shows a similar vegetative habit to that of R. apiculatus , but the former differs by the white, urceolate flowers and the smaller rosette of leaves at flowering time.

Habitat:— Rhodocodon calcicola grows on calcareous plateaus, in deforested areas or in mostly degraded, deciduous relict forests. The area is characterized by a distinct dry savanna climate from April to October, the driest months being June and July. The tropical wet season begins at the end of October; the peak of precipitation is in January and February, with an annual precipitation average of 1486 mm and an annual temperature average of 26.3°C.

Biology:—Flowering and fruiting time comprises November to January.

Distribution:— Madagascar. Province Mahajanga: regions Boeny, Betsiboka and Melaky.

Comments:—Our studies point out that Rhodocodon calcicola , as understood in the present study, includes a certain variation in flower and leaf morphology. As it is not possible to ascertain which flower morphology is present in the specimen collected by Perrier (P 00446354!) due to the pressing, we select a holotype (GZU 000322310!) with defined flower morphology ( Fig. 5 ) to facilitate future works in this aggregate, and to fix the use of the name.

Selected material studied:— MADAGASCAR. Rocailles calcaires ombragées, causse d’Ankara, September 1904, Perrier 10953 (P 00446354!); Ambongo, wooded rocks near Andranomavo, October 1903, Perrier 10952 (P 02160886!); Namoroka (Ambongo), Bois sur calcaire, December 1926, Perrier 17866 (P 02160887!).

Figures

FIGURE 4. Holotype of Rhodocodon calcicola Knirsch, Mart.-Azorín & Wetschnig: Knirsch, Sieder & Andriantiana 6293 (GZU 000322310!).

FIGURE 5. Flower morphology of Rhodocodon calcicola Knirsch, Mart.-Azorín & Wetschnig corresponding to the holotype (GZU 000322310!). Lateral view (left), dissection in lateral view (center) and apical view (right). Scale bar 1 mm.