Scleria rutenbergiana Boeckeler

Goetghebeur, P. & Larridon, I., 2019, A revision of Scleria (Cyperaceae) in Madagascar, Blumea 64 (3), pp. 195-213 : 207

19. Scleria rutenbergiana Boeckeler

Scleria rutenbergiana Boeckeler (1880b) 40. — Type: Rutenberg s.n. (lectotype designated here: BRNU 347461!), Madagascar, Antsiranana, Im Gehölz von Luku bé (Nossi-bé), Apr. 1878.

Perennial rhizomatous. Culm 1–2 m by 2–3 mm, glabrous, scabridous along the edges, reddish. Leaves 20–30 cm by 1.2–1.5 mm, pseudopraemorse, glabrous, margin entire to scabridous; contraligule triangular, apex rounded, glabrous. Inflorescence consisting of panicles in lateral and terminal position, 5 –15 cm long, lax; lateral panicles usually less than 5 cm long, the most basal isolated; bracts leafy. Spikelets unisexual or subandrogynous; rachilla reddish, scabrid; bracts ciliate at the base, up to 2 cm long; glumes 3 mm, straw-coloured. Nutlet 2.5–3 mm diam, globose to ovoid, white, smooth; hypogynium trilobed, lobes truncated, yellowish brown ( Fig. 2k–l ).

Distribution — Endemic to Madagascar.

Habitat & Ecology — In Madagascar, most frequently along the eastern and north-western coasts, alt. 0–1200 m.

Conservation — Scleria rutenbergiana is a widespread species, endemic to Madagascar, occurring in the North Western and Eastern parts of Madagascar. This species is found in Analamazaotra, Betampona, Isalo, Lokobe, Manongarivo and Montagne d’Ambre protected areas. Using all records, the estimated extent of occurrence (EOO) is 193 379 km 2 which exceeds the value of any threatened category. However, the area of occupancy (AOO) is 44 km 2 which is smaller than 2 000 km 2 and meets the threshold of Vulnerable, and its number of locations nearly meets the threshold for Vulnerable (11> 10). Hence, it is here assessed as Near Threatened.

Additional specimens. MADAGASCAR, Tsivendrambendrana, R.N. 70, Z. 27 (P01888460, P0188846, P01888461, P01888462); Antsiranana, Nossibe , Dec. 1857, Boivin s.n. (P01888464); P.N. Montagne d’Ambre, 1400–1475 m, 9–13 Apr. 1993, S. Malcomber et al. 2371 (K, MO); Fianarantsoa, km 23 R.N.25 Mananjary-Ifanadiana, 30 m, 16 Dec. 1997, P. Wilkin et al. 941B (P01888458); Analamazaota, 1908, d’Alleizette s.n. (P01888447); Tananarive, Fotsimano, Dec. 1962, J. Bosser 17028 (P01888449); Toamasina, Mar. 1954, J. Bosser 163 (P01888450); near Toamasina, 20 Sept. 1912, R. Viguier & H. Humbert 195 (P01888454, P01888455); Ste. Marie, May 1847, M. Boivin 1645B (P01888445) .

Note — Our morphological study agrees with both Chermezon (1937) and Bauters et al. (2016) that S. rutenbergiana appears to be related to certain species in sect. Elatae, such as S. terrestris . However, sect. Elatae only occurs in Asia and Oceania, except for S. sumatrensis , which has been recorded from the Seychelles, but is very different from S. rutenbergiana . Alternatively, S. rutenbergiana may belong to sect. Abortivae because of the heart-shaped hypogynium. This would provide a more parsimonius explanation since S. rutenbergiana occurs in the same place where sect. Abortivae diversified.A molecular study is needed to confirm the placement of this species.

Figures

Fig. 2 Nutlets of Scleria species occurring in Madagascar. a–b. S. madagascariensis; c–d. S. trialata; e. S. baronii; f. S. perpusilla; g–h. S. rosea; i–j. S. hilsenbergii; k–l. S. rutenbergiana; m–n. S. angusta; o. S. andringitrensis (a–b: Rakotozafy 2741; c–d: Lance 30; e. Hoffman 221; f. Decary 7695; g–h: Ranarivelo 282; i–j. Rajaonary 45; k–l: Wilkin 941; m–n: Boivin s.n.; o: Perrier de la Bâthie 14385; all K).