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  1. Family: Acanthaceae Juss.
    1. Genus: Ruellia Plum. ex L.
      1. Ruellia domatiata I.Darbysh. & E.A.Tripp

        This species is accepted, and its native range is Madagascar.

    [KBu]

    Darbyshire I. et al. 2017. Ruellia domatiata (Acanthaceae), a striking new species from Madagascar. Kew Bulletin 72:13. DOI 10.1007/S12225-017-9676-7

    Type
    Type: Madagascar, Diego-Suarez, S of Anivorano N, environs of Ambalabao, Cheek, Rakotozafy & Abdallah Salam B1409 (holotype K 000963389!; isotypes BR!, CAS!, COLO!, K 000963390!, K 000963391!, MO!, P!, TAN).
    Habit
    Shrub 1.5 – 3 m tall; young, non-woody stems quadrangular, glabrous except for stiff gland-tipped hairs in the leaf axils; mature stems becoming more terete, woody with pale brown bark with prominent lenticels
    Leaves
    Leaves chartaceous, ovate to oblong-ovate or oblong-elliptic, largest leaves 8.4 – 16 × 3.6 – 6 cm, base often markedly asymmetric, obtuse to rounded or one side more acute, margin entire, apex caudate, sparsely pubescent on margin and midrib above, elsewhere glabrous except for tuft-domatia in axils of lateral veins against midrib comprising tufts of curled, buff-coloured multicellular hairs; both surfaces with numerous sessile patelliform glands and with numer- ous linear cystoliths visible with magnification; lateral veins 6 – 8 (– 10) pairs, strongly ascending, somewhat impressed above, prominent beneath; petiole 4 – 13 mm long, pubescent adaxially
    Inflorescences
    Inflorescences axillary, lax, pendulous 1 – 3 (– 4)-flowered cymes, dichasial or often monochasial or central flower of dichasium suppressed; primary peduncle 30 – 110 mm long, wiry, reddish-brown, proximal portion with short yellowish retrorse hairs adaxially, these becoming sparse in distal portion; secondary peduncles 18 – 33 mm long; bracteoles very early-caducous leaving a pair of prominent scars, linear-lanceolate, ± 9 × 2 mm; pedicels 1.2 – 2.5 mm long
    Calyx
    Calyx tube 4.5 – 5 mm long in flower, up to 7.5 mm long in fruit; lobes 5, linear, somewhat unequal in length with posterior lobe longest, 7.5 – 12 mm long, glabrous externally, appressed-pubescent internally, external surface with dense cystoliths conspicuous above base which is thickened and darker
    Corolla
    Corolla pink-purple with white throat, 33 – 36 mm long during anthesis, glabrous externally except for few stiff hairs on lobe apices; tube infundibuliform, somewhat curved, 21.5 – 24 mm long, basal cylindrical portion 6.5 – 8.5 × 2.2 – 3 mm, throat abruptly expanded, particularly ventrally, 7.5 – 12 mm wide at mouth (flattened); limb 5-lobed, zygomorphic, aestivation left-contort, lateral and adaxial lobes spreading or somewhat reflexed at anthesis; adaxial and lateral lobes oblong, 10.5 – 12 × 7.5 – 8 mm, apices emarginate; abaxial lobe ovate when flattened, 10 – 12 × 9.5 mm, but margin strongly revolute such that lobe appears lanceolate, apex notched
    Stamens
    Stamens included, didynamous, with free portion of filaments ± 10 mm long (longer pair) or ± 4 mm long (shorter pair), glabrous, fused filament curtain ciliate; anthers 3.5 – 3.8 mm long, apex with a conical extension of connective tissue, thecae muticous at base
    Pollen
    Pollen globose, 60 – 65 μm in diam., triaperturate, with coarsely reticulate exine
    Ovary
    Ovary ovoid, 2.5 mm long, glabrous; disk cupular with a protruding lobe on one side; style filiform, 18 – 22 mm long, glabrous; stigma bilobed, posterior lobe minute, anterior lobe linear, 1.2 – 1.5 mm long, flattened but with markedly involute, irregular margin
    Fruits
    Capsule 4-seeded, 21 – 24 mm long, stipitate and with a short rostrum (i.e., sterile portion) to 2.5 mm long, glabrous; seeds only observed in immature state, face somewhat oblong, brown, surfaces appearing smooth but actually covered in dense short appressed hairs, seed base with a semicircular area of thickened pale bony tissue either side of the hilum
    Distribution
    North Madagascar, Antsiranana region (Map 1).
    Ecology
    Ruellia domatiata is recorded from dry semi-deciduous forest and woodland of Garcinia, Pachypodium and Tisonia on limestone at 350 – 450 m alt. This dry forest habitat, which falls within the Western Dry Forest mapping unit of Moat & Smith (2007), is widespread in the karst landscapes of the Ankarana plateau, where the woodland can become xerophytic with a significant succulent element including Aloe, Pachypodium, Euphorbia and Cyphostemma spp.
    Conservation
    Ruellia domatiata is currently known only from a single location just outside the northern boundary of the Ankarana Reserve. It has a known AOO of 8 km2. On Google Earth imagery (accessed 24th February 2016), the forest in the vicinity of the collecting sites is fragmented, with significant amounts of clearance for settlement and agriculture evident. This is confirmed by field observations of extensive deforestation and development in the Ankarana region since the early 1990s (T. F. Daniel, pers. comm.). This area is also subject to mining for precious stones and building materials, and the forests are susceptible to increasingly frequent dry-season fires. All these factors are contributing to a decline in extent and quality of habitat for this species and so, based on our current knowledge, it is provisionally assessed as Critically Endangered – CR B2ab(iii). That said, there are large areas of intact and better protected dry forest on limestone within the Ankarana Reserve, including some extensive patches immediately to the south of the known sites for R. domatiata, and it is considered likely that this species will be found within the Reserve in the future. If this is the case, this provisional conservation assessment may be downgraded to Endangered or Vulnerable.
    Phenology
    From the two specimens seen, it appears that this species flowers at or towards the end of the main rainy season in March, the main rains falling in December – March in this region (Moat & Smith 2007).
    Note
    The tufts of long, curled multicellular hairs in the axils of the principal veins and midrib on the underside of the leaf in this species are here interpreted as tuft-domatia, although there is no evidence of an associated depression or chamber for harbouring arthropods. Domatia have only rarely been recorded in the Acanthaceae: Watson & Dallwitz (2015) noted that they have been reported in three (unspecified) genera in the family, manifested as hair tufts. Tufts of wooly hairs forming domatia in the axils of the major leaf veins have been recorded in the genus Mendoncia Vell. ex Vand. on Madagascar (Magnaghi & Daniel 2014). There are also unpublished records of domatia within the large genus Justicia L. (T. F. Daniel, pers. comm.). Within Ruellieae, leaf domatia have been reported in some species of Mimulopsis Schweinf. and Epiclastopelma Lindau (Vollesen 2008), the latter genus now known to be nested within Mimulopsis (Tripp et al. 2013). To our knowledge, there have been no previous reports of tuft-domatia in Ruellia itself, but ant-occupied cavity domatia — myrmecodomatia — occasionally occur in the stems of the South American R. inflata Rich. (E. A. T., pers. obs.). The species epithet “domatiata” denotes the fact that this species has conspicuous tuft-domatia on the leaves, an unusual character in the genus. Ruellia domatiata is highly distinctive and unlikely to be confused with any other known species of Ruellia. It is allied to R. geayi but is very easily separated by, amongst other characters, having a short corolla tube up to 24 mm long with the basal cylindrical portion shorter than the abruptly expanded throat and with included stamens (vs tube longcylindrical and 45 – 62 mm long, with only a very short expanded throat, and stamens exserted); in the corolla being essentially glabrous (vs densely puberulous externally); in having much longer and wiry peduncles, the primary peduncle 30 – 110 mm long (vs 5 – 23 mm long and rigid, not wiry); in having longer calyx lobes, 7.5 – 12 mm long (vs 1.5 – 6.8 mm long) and in the leaves having tuft-domatia in the axils of the primary veins beneath (absent in R. geayi). In the key to the genus Ruellia in the Flore de Madagascar et des Comores (Benoist 1967), this new species would key out to R. cyanea (Nees) T. Anderson based on the presence of a clavate, stipitate capsule, calyx over 7 mm long and fused in the lower portion, corolla over 20 mm long with tube abruptly widened in the throat and a glabrous ovary. However, the two species are otherwise very different: R. cyanea has sessile or very shortly stalked axillary inflorescences, fruits with up to eight seeds, a more deeply divided calyx with acuminate lobes up to 20 mm long, persistent bracteoles and a pubescent corolla amongst other differences, and so is easily separated from R. domatiata.

    Images

    Distribution

    Native to:

    Madagascar

    Other Data

    Ruellia domatiata I.Darbysh. & E.A.Tripp appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Cheek [B1409], Madagascar K000963389 holotype
    Cheek [B1409], Madagascar K000963388 isotype
    Cheek [B1409], Madagascar K000963387 isotype

    Bibliography

    First published in Kew Bull. 72(1)-13: 2 (2017)

    Literature

    Kew Bulletin

    • Tripp, E. A. & Darbyshire, I. (2017). Phylogenetic relationships among Old World Ruellia L.: a new classification and reinstatement of the genus Dinteracanthus Schinz. Syst. Bot. In press
    • Onjalalaina, G. E. & Darbyshire, I. (2016). An endangered new species of Podorungia (Acanthaceae), with notes on the tribe Barlerieae in Madagascar. Kew. Bull. 71 (3) – 44: 1 – 7. DOI 10.1007/S12225-016-9657-2.
    • Madagascar Catalogue (2015). Catalogue of the Vascular Plants of Madagascar. Missouri Botanical Garden, St. Louis & Antananarivo. [http://www.efloras.org/madagascar. Accessed: January 2016].
    • Watson, L. & Dallwitz, M. J. (2015). The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 8th December 2015. delta-intkey.com
    • IUCN Standards and Petitions Subcommittee (2014). Guidelines for Using the IUCN Red List Categories and Criteria. Version 11. Prepared by the Standards and Petitions Subcommittee. [http://www.iucnredlist.org/documents/ RedListGuidelines.pdf. Accessed: June 2015].
    • Darbyshire, I., Phillipson, P. B. & Rakotonasolo, F. (2014). Additions to the genus Barleria in Madagascar. Kew Bull. 69: 9513. DOI 10.1007/s12225-014- 9513-1.
    • Magnaghi, E. B. & Daniel, T. F. (2014). Three new species of Mendoncia (Acanthaceae) from Madagascar. Novon 23: 187 – 196.
    • Tripp, E. A., Daniel, T. F., Fatimah, S. & McDade, L. A. (2013). Phylogenetic relationships within Ruellieae (Acanthaceae) and a revised classification. Int. J. Plant Sci. 174: 97 – 137.
    • IUCN(2012). IUCN Red List Categories and Criteria. Version 3.1. Second Edition. IUCN Species Survival Commission, Gland & Cambridge.
    • Vollesen, K. (2008). Acanthaceae Part 1. In: H. J. Beentje & S. A. Ghazanfar (eds), Flora of Tropical East Africa. Royal Botanic Gardens, Kew.
    • Moat, J. & Smith, P. (eds). (2007). Atlas of the vegetation of Madagascar / Atlas de la vegetation de Madagascar. Royal Botanic Gardens, Kew.
    • Tripp, E. A. (2007). Evolutionary relationships within the species-rich genus Ruellia (Acanthaceae). Syst. Bot. 32: 628 – 649.
    • Scotland, R. W. & Vollesen, K. (2000). Classification of Acanthaceae. Kew Bull. 55: 513 – 589. Tripp, E. A. (2007).
    • Benoist, R. (1967). Acanthacées. Tome I. In: H. Humbert (ed.), Flore de Madagascar et des Comores. Museum national d’Histoire naturelle, Laboratoire de Phanérogamie, Paris.

    Sources

    Herbarium Catalogue Specimens
    'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Bulletin
    Kew Bulletin
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0