Clinopodium rankiniae, a new species from the SE region of Cuba, is described and illustrated. It appears to be closely related to the other endemic species of Cuba and Hispaniola (C. alpestre, C. banaoense, C. bucheri and C. ekmanianum), which grow isolated in mountainous ecosystems. It differs primarily by the disposition of the leaves (mostly on short, lateral brachyblasts), the colour of the corolla (white, with a very light purple tinge) and the hirsute to tomentose calyx.
Version of record first published online on 1 September 2017 ahead of inclusion in August 2017 issue.
The genus Clinopodium L. (Lamiaceae), sensu Wagstaff & al. (1995), Cantino & Wagstaff (1998) and Harley & Granda Paucar (2000), comprises about 100 species, most in the New World and only some in Eurasia and Africa (Harley & al. 2004). In Cuba, six species of Clinopodium were known (Pool 2008; Greuter & al. 2016), which have been considered indistinctly as Micromeria Benth. (Grisebach 1866; Sauvalle 1873; Gómez de la Maza 1897; Urban 1919; Britton & Wilson 1922; Borhidi 1981) or Satureja L. (Urban 1924a, 1924b; Alain 1956, 1957; Méndez Santos & al. 2005).
While reviewing the genus Clinopodium for the Flora de la República de Cuba, we found a gathering in B, HAJB and JE collected in 1989 in Santa María del Loreto (Sierra de Los Ciegos), Santiago de Cuba province, with characters that differ from all the species hitherto described. Studies of this natural population and comparison with similar taxa from the Greater Antilles, described by Urban (1919), Britton & Wilson (1922), Alain (1968) and Méndez Santos & al. (2005), lead us to propose a new species.
Clinopodium rankiniae I. E. Méndez, sp. nov. — Fig. 1, 2. Holotype: Cuba, Provincia Santiago de Cuba, altiplanicie de Santa María del Loreto, finca Los Monieles, al este de la subestación eléctrica con paneles fotovoltaicos, vegetación secundaria sobre suelos derivados de areniscas y conglomerados, al borde de los farallones, 1 Oct 2016, I. E. Méndez, J. C. Rifá & C. Regalado 12016 (HIPC; isotypes: B, HAC, HAJB, JE, PAL-Gr, ULV).
Description — Shrubs erect, to 2 m tall, usually much branched. Twigs quadrangular, densely covered with a pale tomentose indumentum of tubercle-shaped, bulbous-based, stellate and/or branched hairs (also found on petioles, leaf blades, pedicels, bracteoles and calyxes). Leaves disposed on short, lateral brachyblasts; petiole c. 1 mm long; leaf blade obovate to oblanceolate, 3–10 x 2–5 mm, coriaceous, adaxial surface dark green, veins scarcely sunken, abaxial surface somewhat lighter, veins prominent, both surfaces hirsute-tomentose, more densely so abaxially, base acute to decurrent toward petiole, margin entire, revolute, apex acute or sometimes obtuse. Flowers solitary, inserted in leaf axils on short, lateral brachyblasts; pedicel c. 1 mm long; bracteoles lanceolate to filiform, c. 2 mm long. Calyx narrowly campanulate or cylindric, 2-labiate; tube straight, 2–2.5 mm long, 10–12-nerved, hirsute to tomentose outside; upper lip oblong, 3-dentate, teeth acute, central one lightly longer; lower lip 2-dentate, teeth acute to lanceolate, 1-nerved. Corolla white, with a very light purple tinge, funnelshaped, 2-labiate; tube straight, c. 4.5 mm long; upper lip emarginate; lower lip 3-lobate, lobes rounded to spatulate, c. 1.5 mm long. Stamens 4, c. 1.5 mm long above insertion point in corolla, glabrous, anterior pair slightly exserted from corolla tube. Ovary elongate, glabrous; style exserted. Nutlets elongate, c. 1 mm long, puberulous only in distal third.
Distribution and ecology — Clinopodium rankiniae is known only from the Santa María del Loreto plateau, municipality of La Maya, province of Santiago de Cuba. It grows on a substratum originating from gritty rocks formed by granitic sediments. At this locality, the average annual precipitation is 1200–1400 mm. Associated species include: Bellonia spinosa Sw., Calycogonium rhamnoideum Naudin, Casearia hirsuta Sw., Citharexylum tristachyum Turcz., Guapira obtusata (Jacq.) Little, Ipomoea subrevoluta Choisy, Malpighia suberosa Small and Plumeria filifolia Griseb., among others.
Eponymy — The epithet is in honour of Rosa Rankin Rodríguez, Cuban botanist, co-editor of the Flora de la República de Cuba and member of the team that first gathered the species in 1989.
Affinities — Clinopodium rankiniae is similar to the other four endemic species of Cuba and Hispaniola (Haiti: C. ekmanianum (Epling & Alain) Harley; Dominican Republic: C. alpestre (Urb.) Harley; Cuba: C. banaoense (P. Herrera & al.) Melnikov and C. bucheri (P. Wilson) Harley). All of them are typical of mountainous ecosystems, characterized by a peculiar indumentum on the branches, leaves and inflorescences, with tubercle-shaped, bulbousbased, stellate and/or branched hairs. Within this group, C. rankiniae is more similar to C. alpestre and C. ekmanianum by its leaves being ± compacted on short, lateral brachyblasts and the colour of the corolla being basically white. Clinopodium ekmanianum and C. rankiniae differ from C. alpestre by the obovate to oblanceolate (instead of triangular) leaf blade with a revolute (instead of ± flat) margin. Clinopodium rankiniae is finally distinguished by the hirsute to tomentose calyx and a very light purple tinge of the corolla. Besides, C. rankiniae occurs distant and completely isolated from the species of Hispaniola, to which it is most morphologically similar, and occurs under markedly different geological and edaphic conditions (Cuba: substratum originating from gritty rocks formed by granitic sediments; Hispaniola: soils derived from calcareous rocks).
Melnikov (2014) classified all these species as belonging to Clinopodium subg. Xenopoma (Willd.) Melnikov in Novosti Sist. Vysš. Rast. 45: 148. 2014 [≡ Xenopoma Willd. in Mag. Neuesten Entdeck. Gesammten Naturk. Ges. Naturf. Freunde Berlin 5: 399. 1811 ≡ Micromeria sect. Xenopoma (Willd.) Benth. in Candolle, Prodr. 12: 222. 1848 ≡ Satureja sect. Xenopoma (Willd.) Briq. in Engler & Prantl, Nat. Pflanzenfam. 4(3a): 300. 1895].
Conservation status — Clinopodium rankiniae is at present considered a very rare species. So far, it is only documented in one locality with a total of fewer than 50 mature individuals. The extent of occurrence is smaller than 100 km2 and the area of occupancy is smaller than 10 km2 with proven reduction since 1989. The species can therefore be provisionally assessed as Critically Endangered CR B1ab(ii,iii,v)+2ab(ii,iii,v); C2a(i); D according to the IUCN Red List categories and criteria (IUCN 2012).
Additional specimens seen — Cuba: Provincia Santiago de Cuba: altiplanicie de Santa María del Loreto, finca Los Monieles, al este de la subestación eléctrica con paneles fotovoltaicos, vegetación secundaria sobre suelos derivados de areniscas y conglomerados, al borde de los farallones, 10 May 2016, C. Regalado 12002 (HIPC); Municipio Santiago de Cuba [in error; correctly: Mun. Songo — La Maya], altiplanicie de Santa María del Loreto [Sierra de Los Ciegos], Alto de la Torre, vegetación secundaria sobre caliza [in error; correctly: sobre suelos derivados de areniscas y conglomerados], 3 May 1989, Gutiérrez & al. 67956 (B 100363784, HAJB, JE).
The authors thank César Regalado Díaz, who explored the Santa María del Loreto region unceasingly until locating the new species and who provided invaluable help in the realization of the field studies, and the Moniele family for their support in studying the new species inside their property. We are also grateful to the Botanic Garden and Botanical Museum Berlin for liberal access to the research facilities of that institution and various kinds of help through the collaborative Flora de Cuba programme; to the Verein der Freunde des Botanischen Gartens und Botanischen Museums Berlin-Dahlem e.V. for financial support; and to the directors and curators of many herbaria (B, BM, F, G, GH, HAC, HAJB, JE, MO, NY, S and US) for lending material for the purpose of our study. Dr Rosa Rankin Rodríguez, Prof. Werner Greuter and three anonymous reviewers are acknowledged for their advice on, and critical revision of, earlier versions of this paper.