Hibiscus ankeranensis 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 : 200-201

publication ID

https://doi.org/ 10.15553/c2020v752a4

DOI

https://doi.org/10.5281/zenodo.5708699

persistent identifier

https://treatment.plazi.org/id/190687BC-5A79-4470-A165-6037F3C562A1

treatment provided by

Carolina

scientific name

Hibiscus ankeranensis M. Hanes & G.E. Schatz
status

sp. nov.

Hibiscus ankeranensis M. Hanes & G.E. Schatz , sp. nov. ( Fig. 3B View Fig , 4B View Fig ).

Holotypus: MADAGASCAR. Reg. Atsinanana [Prov. Toamasina]: Dist. Brickaville, Com. Maroseranana, Fkt. Ambodilendemy , Andrangato river , Ankerana , 18°26'52"S 48°46'28"E, 346 m, 13.III.2011, fl., Antilahimena 7544 ( MO-2652132 !; iso-: P [ P06774026]!, TAN). GoogleMaps

Hibiscus ankeranensis M. Hanes & G.E. Schatz differs from H. calyculatus (Hochr.) M. Hanes, G.E. Schatz & Callm. by its epicalyces, 5 non-symmetrical, succulent in vivo lobes (vs. 4 small, reflexed lobes), calyx color, green (vs. red), and its nonreflexed petals.

Tree c. 6 m tall, 12 cm dbh; twigs moderately densely covered with light, golden, semi-erect, simple, fascicled and stellate trichomes. Leaves 3.5– 9.8 × 1.9 –3.9 cm, elliptic to narrowly obovate, the base acute to obtuse, apex acuminate, the acumen to 1.2 cm, sometimes folded to one side, the tip rounded, glabrous and verruculose above, very sparsely covered with golden, stellate trichomes below, venation weakly brochidodromous with 7–10 secondary veins per side, with occasional intersecondary veins, midvein raised above and below, secondary veins slightly raised above and below, tertiary venation finely reticulate, slightly raised above and below; petiole 3–5 mm, 0.7–1 mm in diam., moderately densely covered with semi-appressed, curly light golden trichomes. Flowers solitary, axillary, pendent; pedicels 7–15 mm long, 0.2–0.7 mm in diam., densely covered with golden erect, simple and fasciculate trichomes; epicalyx with 5 free lobes, appearing somewhat succulent in vivo, the lobes 9 × 5 – 7 mm, ovate, the apex acute, sparsely covered with golden stellate trichomes on the outside, glabrous very sparsely covered with golden simple and stellate trichomes inside; calyx tubular with 4(–5?) lobes, fused for 5–7 mm, the lobes 2.5 × 2.5 mm, triangular, the apex triangular, moderately densely covered with golden stellate trichomes outside and inside; petals 5, 24 × 13 mm, obovate, the apex rounded to emarginate, red, sparsely covered with very light golden stellate trichomes outside, glabrous inside with evident venation; staminal column 20 mm long, 0.8 mm in diam., pinkish red, glabrous with very scattered minute trichomes; stamens 30–40(–50), filaments 8–10 mm, red, anthers 0.8 × 0.4 mm; styles 5, 8 mm, red, moderately densely covered with white trichomes, stigma c. 0.7 mm in diam., urceolate. Fruit unknown.

Distribution and ecology. – Hibiscus ankeranensis is known only from a single collection near the Andrangato river at Ankerana in the eastern coast of Madagascar at c. 350 m in elevation in lowland moist evergreen forests ( Fig. 2 View Fig ).

[ A: Ratovoson 2092; B: Antilahimena 7544; C: Razafitsalama 1409] [Photos: A: F. Ratovoson; B: P. Antilahimena; C: C. Birkinshaw]

Conservation status. – Hibiscus ankeranensis is known only from a single collection from the newly designated Corridor Ankeniheny-Zahamena protected area. We lack information on population size but lowland moist evergreen forests (below 800 m) are fragmented and heavily deforested in the region ( GAUTIER, 2018). Recent satellite imagery from Google earth [https://www.google.com/intl/en/earth] suggests that the collection site and the surrounding area is deforested or disturbed. Hibiscus ankeranensis is therefore assessed as “Critically Endangered” [ CR B 2ab(iii)] using IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – Hibiscus ankeranensis is similar to H. calyculatus in corolla color but differs by its epicalyces with 5 lobes, 9 mm long (vs. 4(–5) lobes, reflexed, 3–4 mm long), calyx with 4(–5) teeth, green, succulent in vivo (vs. 5 teeth, red, inflated) and petals not reflexed (vs. reflexed).

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

TAN

Parc de Tsimbazaza

A

Harvard University - Arnold Arboretum

B

Botanischer Garten und Botanisches Museum Berlin-Dahlem, Zentraleinrichtung der Freien Universitaet

C

University of Copenhagen

CR

Museo Nacional de Costa Rica

Kingdom

Plantae

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Malvales

Family

Malvaceae

Genus

Hibiscus