MOSTI, S., M. RAFFAELLI & M. TARDELLI (2011). Barleria almughsaylensis Mosti, Raffaelli & Tardelli (Acanthaceae), a new species from Oman. Candollea 66: 191–197. In English, English and French abstracts.
Barleria almughsaylensis Mosti, Raffaelli & Tardelli (Acanthaceae), a new species from Al Mughsayl area in Oman (Central Dhofar) is described and illustrated. It differs from Barleria acanthoides Vahl, Barleria mucronifolia Lindau and Barleria hillcoatiae J. R. I. Wood by some morphological characters mainly concerning the floral and foliar ones.
Introduction
According to Balkwill & Balkwill (1997) and HEDRÉN (2006) Barleria L. (Acanthaceae) is a genus of perennial herbs or shrubs of about 300 species distributed in tropical and subtropical Africa and Asia, with its greatest centre of diversity in tropical East Africa and one single species (B. oenotheroides Dum. Cours.) in Central America. These plants have leaves entire, dentate or transformed into spines; calyx 4-lobed with 2 outer broader lobes and 2 inner more narrow ones. The corolla is slightly irregular to zygomorphic, funnel-shaped or with cylindrical tube.
Ghazanfar (1992) recorded 5 species of Barleria for Oman in Dhofar: B. acanthoides Vahl, B. aucherana Nees, B. candida Nees (North Oman), B. hochstetteri DC. (North Oman), B. proxima Lindau. Recently Knees & al. (2007) discovered another new species in Dhofar: B. samhanensis Knees, A. G. Mill. & A. Patzelt.
Floristic investigations in Dhofar (2000–2009) have been conducted to explore the hills and valleys surrounding the coastal village of Al Mughsayl. In four different localities specimens of Barleria were collected, which appeared quite different in vegetative habit and in flower shape from the other related known species.
Barleria almughsaylensis Mosti, Raffaelli & Tardelli, spec. nova (Fig. 1-3)
Typus: Oman. Dhofar: Al Mughsayl, wadi in fondo alla discesa, pochi km dopo Al Mughsayl, 111 m, 16°52.096′N 53°42.931′E, 15.II.2006, M. Raffaelli, M. Tardelli & S. Mosti 377 (holo-: FT!).
A Barleria acanthoidea corolla minore et lobis calycis superioribus armatis potius quam subinermibus differt. A Barleria mucronifolia fistula corollae omnino cylindrata potius quam in parte superiore infundibuliforme ac indumento foliorum differt.
Spiny shrub up to ca. 40–50 cm tall, branched from the base. Branches light grey-brown, sparsely to densely pubescent (in the young parts) with hairs 0.1–0.2 mm long. Leaf-blades entire, ovate to suborbicular, 4–17 × 3–11 mm; adaxial surface greygreen with hairs 0.1–0.2 mm long and sparse hairs 0.5 mm long; abaxial surface grey with dense and appressed hairs 0.1–0.2 mm long and sparse acicular hairs with a slightly bulbose base, 0.5–0.7 mm long, placed along the venations and the margin; apex mucronate, with a spine 0.5–1 mm long. Leaves on axillary shoots pubescent, pungent with a very reduced blade, up to 28 × 1.5(-3) mm including the long apical spine (ca. 20 mm) and with 2(-3) pairs of lateral spines up to ca. 5 mm long. Flowers in dense scorpioid cymes (in the leaf-axils). Bracts leaf-like. Bracteoles with a more or less reduced blade, up to 35 × 8 mm including the long apical spine (ca. 20 mm) and with 5–11 pairs of lateral spines up to 5 mm long. Calyx lobes 4, pubescent in the abaxial side and sparse pilose or subglabrous in adaxial side. Upper lobe (of the 2 outer calyx lobes) up to ca. 27 × 14 mm long including an apical spine (ca. 8–9 mm long) and up to 9 pairs of lateral spines up to 4 mm long. Lower lobe ovate-acute up to 19 × 13 mm without an apical spine but with 8–10 pairs of very short lateral spines 0.5–1 mm long. Inner calyx lobes 2, linear-acute up to 9 × 1.5 mm. Corolla white, turning blue on drying, 38–52 mm long, with a cylindrical tube 35–49 mm long and 5 obovate-elliptical lobes up to 12 × 7 mm, almost perpendicular to tube. Capsule 4-seeded, up to 14 × 5 × 2 mm, ellipsoidal with a conical apical beak ca. 1 mm long; pale to medium brown with 3 darker stripes, glabrous or with sparse short hairs. Seeds ca. 4 × 4 mm, trapezoidal-suborbicular, flattened, brown with a thick horn-coloured margin, sometimes showing sparse protuberances; seeds surface covered with dense, intricate hairs, white-beige in colour and hygroscopic.
Phenology. — Reproductive stage in January-February and September-November.
Etymology. — Named from Al Mughsayl area where it was discovered.
Distribution and ecology. — Up to now B. almughsaylensis has been collected in the above mentioned localities. ‘Locus classicus' is placed inside an arid sparse shrubland of Boswellia sacra Flueck (the frankincense tree). Other shrubby and herbaceous species living in the area were: Caesalpinia erianthera Chiov., Euphorbia uzmuk S. Carter, Polygala cf. obtusissima Chod., Campylanthus pungens O. Schwartz, Echiochilon arabicum (O. Schwartz) I. M. Johnst., Lavandula macra Baker, Iphiona senecionoides (Baker) Anderb., Tetraena alba (L. f.) Beier & Thulin, Fagonia mahrana Beier and the rare Desmidorchis adenensis (Defl.) Meve & Liede.
Taxonomical notes. — In our opinion these specimens can be referred to a new species related to sect. Barleria L. (such as B. achanthoides) because of the number of seeds in the capsule (4), the shape and the size of the spines that are 2, branched and sessile. Among the other Barleria of Oman, B. candida, B. proxima and B. samhanensis belong to sect. Prionitis (Nees) Lindau, having only 2 seeds instead of 4, 4 simple spines together on a short common stalk; while B. aucherana and B. hochstetteri belong to sect. Somalia (Oliv.) Lindau being unarmed plants.
Barleria almughsaylensis is added to the 17 species (7 endemic) widespread in the Arabian Peninsula and Socotra (Balkwill & Balkwill, 1997). The new species belongs to sect. Barleria, the more widespread in the genus (absent only in the New World), in all including 79 species, 6 of which are now found in Arabia and Socotra. Among the species of sect. Barleria, B. almughsaylensis is related to those with spinescent habits and/or weakly zygomorphic flowers (Balkwill & Balkwill, 1997).
Fig. 1.
Holotypus of Barleria almughsaylensis Mosti, Raffaelli & Tardelli.
[Raffaelli, Tardelli & Mosti 377, FT] [© Centro Studi Erbario Tropicale]
Fig. 2.
Details of Barleria almughsaylensis Mosti, Raffaelli & Tardelli.
[Raffaelli, Tardelli & Mosti 377, FT]
Fig. 3.
Details from the inflorescence of B. almughsaylensis Mosti, Raffaelli & Tardelli. A. Bracteoles ; B. Upper outer lobes of calyx ; C. Lower outer lobes of calyx ; D. Inner calyx lobes ; E. Capsule; F. Seed.
Barleria almughsaylensis differs from B. acanthoides Vahl in having the upper of the 2 outer calyx lobes spiny, the tube of corolla shorter and some other different morphological characters, as shown in Table 1 (as the specimens of B. acanthoides and B. mucronifolia kept in FT have leaves on axillary shoots (spines) and narrower bracteoles compared with the descriptions reported in Hedrén (1997), it should be important to verify this character on a larger number of specimens of B. acanthoides Vahl and B. mucronifolia Lindau). It shows also affinity with B. mucronifolia Lindau., a species from Yemen, Somalia and Ethiopia that, in the opinion of Hedrén (2006), includes also B. homoitricha C. B. Clarke and B. jodocephala Chiov. Nevertheless, B. mucronifolia is characterized by a widened and funnel-like (in the upper part) corolla, by a longer mucro on the leaf apex and by a different indumentum on the leaves (see Table 1). Finally a comparison should be made with B. hillcoatiae J. R. I. Wood from Yemen (Wood, 1984), but this last species has the upper of the 2 outer calyx lobe with only 2 pairs of lateral spines (up to 9 pairs in B. almughsaylensis), the lower of the outer calyx lobes with an apical spine (the lower lobe is without an apical spine in B. almughsaylensis) and with 2 pairs of lateral spines 0.8–10 mm long (in the B. almughsaylensis these are 8–10 pairs but only 0.5–1 mm long). Besides the leaves of B. hillcoatiae have dense white marginal hairs (Wood, 1997), segments of the calyx white-villous and the corolla tube longer: up to 120 mm.
The taxonomic comparison between B. almughsaylensis and the above mentioned closely related species has been made by analysing the characters of taxonomic importance (such as the calyx and the corolla morphologies) according to Balkwill & Balkwill (1997) and Hedrén (1997). Moreover also the indumentum of the leaves (length and shape of the hairs) has been taken into account, being considered a speciesspecific character by Ahmad (1978). Finally, the difference in colour of the hygroscopic hairs of the seed is useful for distinguishing closely related species in this group (Balkwill & Balkwill, 1997).
Table 1.
Main differential characters between Barleria almughsaylensis Mosti, Raffaelli & Tardelli, B. mucronifolia Lindau and B. acanthoides Vahl.
Relationships. — The new species appears closely related to B. acanthoides Vahl (among the species of Oman) and to B. mucronifolia Lindau, a wide range species known for Yemen, Somalia and Ethiopia. These three species belong all to sect. Barleria.
Additional material examined. — Oman. Dhofar: Mugsail. 16°45′N 53°40′E, 13.XI.1984, I. McLeish 327 (sub B. acanthoides) (E!); Wadi Afal, ca. 40 km of Mugsail on new road to West., 200 m, 16.IX.1989, A. G. Miller & J. A. Nyberg M. 9404 (sub Barleria acanthoides) (E!); strada Al Mughsayl-Salalah, 5 km dopo Al Mughsayl: costone roccioso, 45–100 m, 16°53′76″N 53°48′95″E, 27.IV.2001, M. Raffaelli, M. Tardelli & S. Mosti 588 (FT!); dopo Al Mughsayl verso Ajdarawt, costone roccioso versante a mare, 476–965 m, 16°49.785′N-16°51.305′N 53°43.275′E-54°40.006′E, 15.II.2006, M. Raffaelli, M. Tardelli & S. Mosti 367 (FT!); dopo Al Mughsayl lungo la strada verso Ajdarawt, rilievi del versante a mare poco prima del posto di blocco, 965 m, 16°49.785′N 53°40.006′E, 27.II.2007, M. Raffaelli, M. Tardelli & S. Mosti 38 (FT!).
Acknowledgments
Thanks are due to the Office of the Adviser for Cultural Affairs, Sultanate of Oman, for logistic assistance during our visit to Dhofar. Thanks also to the Royal Botanic Garden Edinburgh-Herbarium for sending us the specimens of Barleria from Al Mughsayl.
