Rhodocodon urgineoides Baker (1896

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 : 129-131

13. Rhodocodon urgineoides Baker (1896 : t. 2492)

≡ Rhadamanthus urgineoides (Baker) Speta (1998: 77) ≡ Drimia urgineoides (Baker) Manning & Goldblatt (2004: 557) .

Illustrations:—pl. 2492 in Baker (1896); fig. XVI (12 ‒ 13) in Perrier de la Bâthie (1938: 121).

Type (lectotype here designated):— MADAGASCAR. Ivohimanitra forest , October 1894, C.H. Forsyth Major 44 (G 00168520!, Fig. 25 ; isolectotype K 000099856!)

Description:—Perennial bulbous plant, 25 ‒ 45 cm high. Bulb epiphytic, growing in moss, sometimes in rocks, 2.3 ‒ 3 × 3 ‒ 4 cm, ovoid to subglobose; roots white to pale brown, numerous, branched. Leaves 2 ‒ 5 per bulb, evergreen, 17 ‒ 30 × 1.7 ‒ 2.2 cm, ensiform to oblanceolate, usually distichously arranged, acute, with hyaline margin. Inflorescence an erect raceme; peduncle 20 ‒ 40 × 0.25 cm, bright green, smooth; raceme 10 ‒ 30 cm long, with 8 ‒ 30 flowers; pedicels 8 ‒ 11 mm long, spreading to subpatent; lowermost bracts 2.5 ‒ 5 mm long, lanceolate, green, with a petiole that sheaths the pedicel, spur 3 ‒ 4 mm long, oblong; bracteoles present; flowers nodding, white, with a pale green central band of the tepals on the upper portion. Perigone campanulate, 8 ‒ 9 × 4.4 ‒ 6 mm, tepals connate for most of their length, lobes ca. 1 × 1 mm, spreading to patent or slightly reflexed. Stamens 6; filaments adnate to the perigone tube and arising from its basal portion; free portion of filaments ca. 2 mm long, narrowly strap-shaped, smooth; anthers pale green, sagittate-oblong, ca. 1.7 mm long, basifixed. Ovary ovoid, ochre, ca. 2.5 × 2 mm, with about 17 ovules per locule; style ca. 1.3 mm long, attenuate to the apex; stigma annular. Capsule conical, triangular in section, ca. 12 × 10 mm, with 13 ‒ 15 seeds per locule. Seeds flattened fusiform, sometimes slightly bent, L-H-W: 6 ‒ 1.9 ‒ 0.4 mm, light brown, with a vweak gloss, without a distinct raphe. Fig. 26 .

Diagnosis:— Rhodocodon urgineoides is easily distinguished by the somewhat distichously arranged leaves, the large white nodding campanulate flowers, and the light, flat, brown seeds with small endosperm.

Habitat:— Rhodocodon urgineoides is mostly epiphytic, with the bulbs growing in moss on trees or rocks; sometimes terrestrial, found in evergreen humid forest, at elevations of 300 ‒ 1650 m. The region supports wet subtropical forest. The highest temperatures occur from January to March (mean of 30°C), and the lowest temperatures were recorded from July to September (mean of 17°C). The highest precipitation is between January and March (410 ‒ 478 mm), and the lowest between September and October (121 ‒ 133 mm).

Biology:—Flowering and fruiting time: October to February.

Distribution:— Madagascar, Province Antsiranana: District Diana and Sava; Province Toamasina: District Analanjirofo, Alaotra-Mangoro and Atsinanana; Province Fianarantsoa: District Vatovavy-Fitovinany; Province

Toliara: District Atsimo-Atsinanana. Rhodocodon urgineoides occurs along the humid eastern zone of Madagascar.

The species also spreads to the western part of Madagascar along the Sambirano valley. It is the Rhodocodon species with the largest distribution area.

Comments:—This species shows a certain variation in the density and length of the inflorescence, and the length of the pedicels. Further studies are needed to clarify the nature and significance of those variations.

Selected material studied:— MADAGASCAR. Prov. Fianarantsoa: District Atsimo-Atsinanana, Midongy du Sud , 534 m, 2 November 2006, W. Knirsch, A. Sieder & J. Andriantiana 03850 ( GZU!) ; Toamasina- Moramanga, Bekorakaka, 17 km de la RN 4 vers Lakato , forêt dense humide, sol laterituque, forêt basse à mousse, 1000 m, 23 November 2005, J.N.Labat et al. 3590 (P 00533632!) ; Antsiranana, Reserve Naturelle de Marojejy ; along the trail to the summit of Marojejy Est, N of Mandena ; steep slope above the 2nd camp; premontane rainforest, epiphyte, 700 ‒ 900 m, 24 November 1989, J.S. Miller & A. Randrianasolo 4556 (P 02160898!); Prov. Tamatave, Reserve Speciale Analamazaotra ( Périnet ), Forest east of Station de pisciculture, epiphytic, 4 November 1985, L.J. Dorr, L.C. Barnett, A. Gentry & A. Rakotozafy 4338 (P 02160897!) ; Fianarantsoa, Ivohibe, Ivongo, Ambahatsy , RNI, Andringitra , au 2e campement dans la forêt humide, Forêt coupée par la rivière d’Iatara , 810 m, 6 October 1994, J.B. Razafindrabe et al. 101 (P 02160905!) .

Figures

FIGURE 25. Lectotype of Rhodocodon urgineoides Baker: Forsyth Major 44 (G 00168520!).

FIGURE 26. Flower morphology of Rhodocodon urgineoides Baker (corresponding to WW 2521!). Lateral view (left), dissection in lateral view (center) and apical view (right). Scale bar 1 mm.