Hibiscus analalavensis M. Hanes & G.E. Schatz, 2020

Hanes, Margaret M., Schatz, George E. & Callmander, Martin W., 2020, Transfer of the Malagasy genera Humbertianthus and Macrostelia to Hibiscus (Malvaceae) with description of four new species, Candollea 75 (2), pp. 193-202 : 198-200

Hibiscus analalavensis M. Hanes & G.E. Schatz , sp. nov. ( Fig. 3A , 4A ).

Holotypus: MADAGASCAR. Reg. Atsinanana [Prov. Toamasina]: Analalava NP, 17°42'S 49°26'E, 16.XI.2007, fl., Andriamiarinoro 102 ( MO-6562524 !; iso-: P [P00847913 ]!, TAN).

Hibiscus analalavensis M. Hanes & G.E. Schatz differs from H. vohipahensis M. Hanes & G.E. Schatz in having shorter petioles, 4–5 mm (vs. 6–10 mm), and shorter pedicels, 30–32 mm (vs. 45 mm).

Shrub to small tree 3–5 m tall, 3–4 cm dbh; twigs moderately densely covered with golden stellate trichomes. Leaves 7.3–11.9 × 3.3–5.1 cm, narrowly obovate, the base cuneate and abruptly attenuate, the margin strongly revolute, the apex rounded to obtuse or slightly retuse, glabrous above, nearly completely glabrous below, venation brochidodromous with 6–7 secondary veins per side, midvein raised above and below, secondary veins slightly raised above and below, tertiary venation reticulate, slightly raised above and below; petiole 4 – 5 mm, c. 1 mm in diam., moderately densely covered with stellate trichomes. Flowers solitary, axillary, pendent; pedicels 30 –32 mm long, 1.4 mm in diam., densely covered with reddish-gold, erect simple, fasciculate and stellate trichomes; epicalyx with 5 lobes fused at the base for 2 mm, the lobes 15 × 6– 9 mm, broadly ovate, the apex acute, densely covered with rufous golden stellate trichomes on the outside, densely covered with golden appressed simple and fasciculate trichomes inside; calyx with 5 lobes, fused at the base for 6–9 mm (c. half of length), the lobes 20 × 18 mm, triangular, the apex triangular, very densely covered with golden stellate trichomes outside, very densely covered with appressed curly white trichomes inside; petals 5, 50 × 35– 37 mm, obovate, the apex rounded, white with a peach blush, meanwhile they turn from pink to white with age, densely covered with light golden stellate trichomes outside, glabrous inside with evident venation; staminal column c. 30 mm long, c. 2 mm in diam., white, glabrous, with a tuft of dense, golden, erect, simple trichomes at the apex; stamens c. 70, filaments 10 mm long, white, anthers c. 1.5 × 1.5 mm; styles 5, c. 16 mm long, white, slender, moderately densely covered with white, erect, simple and fasciculate trichomes, stigma c. 0.5 × 0.8 mm, bulbous. Fruit unknown.

Vernacular names. – “Afopotsy” (Lehavana 426).

Distribution and ecology. – Hibiscus analalavensis occurs in the lowland moist evergreen forest of Analalava near Foulpointe from 40 to 90 m in elevation.

Conservation status. – Hibiscus analalavensis is known from 4 locations within the protected area of Analalava. Despite the very restricted extent of occurrence (EOO) (c. 1 km ²), there appear to be no current threats to H. analalavensis . Thus, the species is assigned a status of “Least Concern” [LC] using IUCN Red List Categories and Criteria ( IUCN, 2012), with the caution that this status is highly dependent on continued effective protection.

Notes. – Hibiscus analalavensis resembles H. vohipahensis in that they have whitish flowers but differs from the latter species by having shorter petioles, 4–5 mm (vs. 6–10 mm), shorter pedicels, 30–32 mm (vs. 45 mm), and smaller petals, 15 × 6–9 mm (vs. 12–17 × 12–18 mm).

Paratypi. – MADAGASCAR. Reg. Atsinanana [Prov. Toamasina]: Foulpointe, Morarano, forêt d’Analalava , à 7 km SW de Foulpointe, 17°42'05"S 49°27'31"E, 87 m, 12.II.2007, fl., Lehavana 426 ( MO, P, TAN); ibid. loco, 17°42'14"S 49°27'19"E, 40 m, 25.XI.2015, fl., Ratovoson 2092 ( MO, P, TAN); ibid. loco, 19.XII.1967, fl., Service Forestier 28071 ( P).

Figures

Fig. 3. – Photographs of flowers of Hibiscus L. A. Hibiscus analalavensis M. Hanes & G.E. Schatz; B. Hibiscus ankeranensis M. Hanes & G.E. Schatz; C. Hibiscus vohipahensis M. Hanes & G.E. Schatz. [A: Ratovoson 2092; B: Antilahimena 7544; C: Razafitsalama 1409] [Photos: A: F. Ratovoson; B: P. Antilahimena; C: C. Birkinshaw]

Fig. 4. – Photographs of epicalyx and calyx of Hibiscus L. A. Hibiscus analalavensis M. Hanes & G.E. Schatz; B. Hibiscus ankeranensis M. Hanes & G.E. Schatz; C. Hibiscus vohipahensis M. Hanes & G.E. Schatz.