Rhodocodon longistamineus Mart.-Azorín, Knirsch, Andriant. & M.B.Crespo, sp. nov. (Figs 1–3)

Diagnosis:— Rhodocodon longistamineus slightly approaches R. cryptopodus based on the suberect flowers with spreading upper portion of tepals, but the former differs by the long inflorescence and flower pedicels; tepals mostly free; stamens distinctly elongated and exserted, suberect, slightly incurved; the very long style; and the narrowly trigonous, claviform, pointed seeds with elongated sinuous testa cells.

Type:— MADAGASCAR. Prov. Mahajanga: Sofia Region, Befandriana-Avaratra (= Befandriana-Nord) district, on RN32, between Ampombilava and Ankobakobaka, on a granitic hill, elev. ca. 300 m, ex hort. in Sankt Marein, Austria, 23 December 2018, W. Knirsch, A. Sieder & J. Andriantiana coll. num. SK06476 (ABH84805 holotype).

Deciduous, perennial, bulbous plants to 100 cm tall. Bulb solitary, usually growing in clumps inside grass tufts, hypogeal, ovoid to subglobose, 2.5–4 × 2.5–3.5 cm, with imbricate, pale brown or greenish outer tunics. Roots fleshy, branched, white, to 50 mm long. Leaves 6–10 per bulb, hysteranthous or synanthous in cultivation, narrowly linear and tapering to the apex, 20‒35 × 0.2‒0.3 cm when fully developed, acute, suberect, green, smooth, glabrous, flattened and slightly canaliculate. Inflorescence a raceme 10–50 cm long, with (6–)10–40 flowers; lowermost pedicels 10–23 mm long, grey-green to purplish, glaucous, smooth, erect-patent at anthesis and erect in fruit, then elongating to ca. 25 mm; peduncle erect or slightly inclined, 30–50 cm long and ca. 3 mm wide, glabrous, smooth, grey-green to purplish, glaucous, smooth; bracts narrowly lanceolate, acuminate, purplish, 2.5–5 × 1–1.2 mm, shorter than pedicels, shortly spurred, with spur ca. 1 mm long, early caducous, bracteoles present, small, 0.7–1.2 mm long, white, membranous, appearing on alternate sides. Flowers suberect to patent, campanulate; tepals 6, biseriate, obovate-lanceolate, 11–15 × 3–4 mm, white, with a thin, green to reddish median stripe, more evident on the abaxial side distally, with minutely glandulous apex, only shortly connate for ca. 1 mm, spreading along the basal half and overlapping laterally to form a campanulate structure and patent to slightly reflexed along the upper half. Stamens 6, homomorphic, distinctly elongated and exserted; filaments 12–14 × 0.5–0.6 mm, shortly adnate to tepals for ca. 1 mm, white, linear, cylindrical, suberect, slightly incurved and connivent to ovary at base, approaching the style along the middle and slightly spreading above; anthers pale yellow, basifixed, dehiscing longitudinally along their whole length, introrse, ca. 2.5 mm long before dehiscence, ca. 1.2 mm long after dehiscence, with yellow pollen. Ovary subglobose to ellipsoid, 2.6–2.9 × 1.9–2 mm, greenish with a purplish tinge distally, with small whitish maculae, trigonous and subcylindrical in transversal section, with 3 septal nectaries, with ca. 20 ovules per locule; style filiform, suberect or curved, 14–17 × 0.5–0.6 mm, stigma only slightly thickened, trigonous, glandulous. Capsule subglobose to ellipsoid, ca. 8–9 × 6–7 mm, trilobed in section, pale-brown when mature, with valves splitting to the base, withered tepals cohering and twisted above and circumscissile below, remaining as a cap at the top of the developing capsule or laterally attached. Seeds narrowly triangular, polyhedral, L-H-W: 2.6–3 × 1–1.2 × 1–1.2 mm, pointed, claviform with flattened sides except the parietal one which is rounded, edges slightly winged, lacking a raphe, black, glossy, with elongate-sinuous testa cells and slightly prominent anticlinal walls.

Etymology:—The specific epithet, longistamineus (from the Latin words “ longi ”, long, and “ stamineus ”, related to stamens), refers to the very long stamens, which are clearly exserted. This character distinguishes the new species from all other members of Rhodocodon, which show much shorter, included stamens.

Phenology and biology: — Rhodocodon longistamineus flowers in the wild around October-November, and fruits and seeds are set around November-December. In cultivation in the Northern Hemisphere (Sankt Marein, Austria) it starts flowering in September (rarely also in May), when leaves also appear, having synanthous or hysteranthous behaviour, and flowering extends until December. Ripe fruits and seeds are present around December and January.

Flowers are diurnal and first open in the early morning. The freshly opened flowers present erect and connivent stamens, and erect style, with the stigma only shortly overtopping non-dehisced anthers. As the flowers matures, the style elongates and usually curves on one side (enantiostyly) to remain apart from the dehisced, introrse anthers that present pollen. As flowers wither, the tepals cohere and enrol distally to reveal the exserted anthers and style, which is a distinct character of the species. Developmentally, the withered tepals with their adnate stamens are basally circumcised and remain either at the top of the developing capsule, or break laterally to remain on one side.

Habitat: — Rhodocodon longistamineus grows in tropical dry forest on the slopes of rocky granitic outcrops with bulbs typically associated with grass tufts (Fig. 1). This region in which it occurs is characterized according the Köppen-Geiger climate classification system as part of the Tropical monsoon climate (Am) Zone. The mean annual temperature is around 30°C (maximum ca. 37°C, minimum ca. 18°C). Precipitation ranges from a maximum (450– 1000 mm) in January, to a minimum (marginally above 0 mm) in June. The area of distribution comprises a mosaic of dense vegetation and open grassland.

Distribution:— Rhodocodon longistamineus is only known from the surrounds of Befandriana and Mandritsara, in the Sofia Region of northeastern Madagascar (Fig. 4). Further studies are necessary to evaluate its actual occurrence and its conservation status.

Diagnostic characters and taxonomic relationships:— Rhodocodon longistamineus is unmistakably identified by its combination of: elongated inflorescence; shortly spurred bracts and small bracteoles; pedicellate, erect-patent, campanulate flowers; elongated tepals only very shortly connate at the base, suberect-spreading and overlapping in the basal half and patent along the upper portion; stamens very shortly adnate to tepals, distinctly elongated and exserted, suberect, slightly incurved and connivent to the ovary at its base, approaching the style along the middle and spreading above; the elongated and usually curved style; and the distinctly trigonous, claviform, pointed seeds with elongated sinuous testa cells. It slightly approaches Rhodocodon cryptopodus (Baker 1883: 274) Knirsch et al. (2015: 112) based on the suberect flowers with the upper portion of tepals free and spreading. However, R. cryptopodus clearly differs by its wider leaves (1–1.5 cm wide at anthesis), much shorter penduncle (5–7 cm long) and pedicels (1–3 mm long), its pinkish flowers with tepals connate for about half of their length, stamens included with shorter filaments (3–3.5 mm long), its shorter style (ca. 5 mm long) and by its hemiellipsoidal seeds with a distinct raphe (Knirsch et al. 2015). All other known Rhodocodon species show nodding, campanulate or urceolate flowers with tepals connate for most of their length and free portions very short and usually spreading-reflexed, stamens included and connivent to the ovary and style, and ellipsoid or flattened seeds (Knirsch 2012, Knirsch et al. 2015, 2016, 2019).

The discovery of R. longistamineus after ca. 40 years and its subsequent circumscription could be considered as undermining of the generic concept for Rhodocodon accepted by Knirsch (2012), Knirsch et al. (2015, 2016, 2019) and Martínez-Azorín et al. (2023a, 2023b), given that characters such as near- free tepals and exserted stamens substantiate their genus concept. However, as discussed by these authors, connation of tepals alone must not be used for generic delimitation in Hyacinthaceae, since some genera show free or connate tepals, such as Austronea Mart.-Azorín, M.B.Crespo, M.Pinter & Wetschnig in Martínez-Azorín et al. (2018: 105), Nicipe Rafinesque (1837: 54) or Urginavia Speta (1998: 86), and the same applies to the adnation of stamens to tepals, as in Iosanthus Martínez-Azorín et al. (2019: 584). However, when the whole range of morphological characters is considered and they are linked to enough phylogenetic and biogeographic evidence, clear generic recognition is realised. This is the case of R. longistamineus, where our unpublished phylogenetic study (in prep./unpubl. data) confirms its inclusion in Rhodocodon and its position sister to R. jackyi Knirsch, Mart.-Azorín & Wetschnig in Knirsch et al. (2016: 202) and R. mascarenensis (Baker 1874: 363) Knirsch, Mart.-Azorín & Wetschnig in Knirsch et al. (2015: 122), although still with a limited sampling. Despite its almost free tepals and elongated stamens, the overall flower morphology is retained, being campanulate and therefore probably linked to a similar pollination syndrome in the genus. Stamens, despite their elongated and exserted nature, share with all other genus members connivence to the style and adnation to the tepals. The trigonous, pointed, claviform seeds are also unique in the genus, but are accommodated without disruption when considering the previously reported large variation in seed morphology, ranging light and flattened to heavy and hemiellipsoidal with a distinct pronounced raphe (Brudermann et al. 2018, 2019). Finally, all known Madagascan species of subfamily Urgineoideae so far belong to Rhodocodon, a morphological divergent genus endemic to Madagascar; R. longistamineus further supports acceptance of this independent evolutive linage.

History:— Rhodocodon longistamineus was first collected by the French-Mauritian orchidologist Jean M. Bosser in the Mandritsara and Befandriana-Nord areas of Madagascar in 1962 and 1963. He prepared three herbarium vouchers currently deposited at P corresponding to two gatherings (P01848508, P01848510, P02160909), although lacking species identification details. The two vouchers P01848508 and P01848510, which corresponding to a single gathering from Mandritsara, were annotated by T.D. Macfarlane in 2006 as “ Drimia sp. nov. 1”, but the voucher P02160909 remained undetermined. Our collection from Befandriana perfectly fits the cited vouchers at Herb. P, and the study of fresh material in flower and fruit confirms its autonomy as a new species of Rhodocodon, further supported by our phylogenetic studies (in prep./unpubl. data).

Additional material studied (paratypes):— MADAGASCAR. Prov. Mahajanga: Sofia Region, Befandriana-Nord, route Mandritsara, rochers, October 1962, J. Bosser 16724 (P01848508!, P01848510!); Prov. Mahajanga: Sofia Region, Befandriana-Nord, rochers, November 1963, J. Bosser 17473 (P02160909!); Prov. Mahajanga: Sofia Region, Befandriana-Avaratra (= Befandriana-Nord) district, on RN32, between Ampombilava and Ankobakobaka, on a granitic hill, elev. ca. 300 m, ex hort. in Graz Botanical Garden, Austria, 21 November 2014 (in flower), W. Knirsch, A. Sieder & J. Andriantiana Coll. num. SK06476 (ABH82522!); ibidem, ex hort in Graz Botanical Garden, Austria, 14 December 2014 (leaves) (ABH82523!); ibidem, ex hort. in Graz Botanical Garden, Austria, 05 May 2015 (leaves and flowers) (ABH82521!).