Hibiscus calyculatus (Hochr.) M. Hanes, G.E. Schatz & Callm., 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 : 194-196

Hibiscus calyculatus (Hochr.) M. Hanes, G.E. Schatz & Callm. , comb. nov. ( Fig. 1A ).

 Macrostelia calyculata Hochr. in Notul. Syst. (Paris) 14: 232. 1952.

Holotypus: MADAGASCAR. Reg. Haute Matsiatra [Prov. Fianarantsoa]: vallée Ampamaherana, [21°19'S 47°19'E], [1300 m], 25.V.1949, fl., Service Forestier 2046 ( P [ P00037125 ]!; iso-: G [ G00014441 ]!, TEF) .

Vernacular name. – “Tsilaitra” (Service Forestier 2046, 14420).

Distribution and ecology. – Hibiscus calyculatus grows in medium elevation moist evergreen forests east of Fianarantsoa, in the massif of Andrambovato, in the Ampamaherana valley and near Kianjavato (D. Scherberich, pers. comm.) from 1155–1300 m in elevation ( Fig. 2 ).

Conservation status. – Hibiscus calyculatus is known from 3 locations all encompassed in the Protected Area Network (Corridor Forestier Ambositra-Vondrozo and Ranofanana). Despite the very restricted Extent of Occurrence (EOO) of 12 km ² and an Area of Occupancy (AOO) of 8 km ², there appear to be no current threats to H. calyculatus . Thus, the species is assigned a conservation status of “Least Concern” [LC] using the IUCN Red List Categories and Criteria ( IUCN, 2012), with the caution that this status is highly dependent on continued effective protection.

[B: Rasoandriana 89; C: J. Razanatsoa 644] [Photos: A: D. Scherberich; B: P. Antilahimena; C: B. Mashburn]

Notes. – Hibiscus calyculatus is distinguished from all other pendent Hibiscus on Madagascar by its four small (3–4 mm), free, reflexed epicalyx bracts and a distinctive red, tubular calyx.

Additional specimens examined. – MADAGASCAR. Reg. Vatovavy-Fitovinany [Prov. Fianarantsoa]: Massif d’Andrambovato, Tolongoina, Ikongo , 21°30'58"S 47°25'36"E, 1155 m, 28.V.1998, fl., Razafimandimbison 335 ( G, MO, P, TAN, TEX); Fort Carnot, Andrambovato Station Forestier , Parcelle A-16, [21°31'S 47°25'E], 28.VII.1954, fl., Service Forestier 14420 ( P, TEF) .

Figures

Fig. 1. – Photographs of flowers of Hibiscus L. A. Hibiscus calyculatus (Hochr.) M. Hanes, G.E. Schatz & Callm.; B. Hibiscus laurinus Baill.; C. Hibiscus ambanitazensis M. Hanes & G.E. Schatz.

Fig. 2. – Known distribution of the seven species of Hibiscus L. highlighted in this paper.