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This species is accepted, and its native range is SW. Namibia.

[KBu]

Darbyshire, I., Tripp, E.A. & Chase, F.M. (2019). A taxonomic revision of Acanthaceae tribe Barlerieae in Angola and Namibia. Part 1. Kew Bulletin 74: 5. https://doi.org/10.1007/s12225-018-9791-0

Conservation
This species is restricted to a small range in southwest Namibia, with an EOO of 8901 km2, and is known from few collections. Most of the known localities are found on private farms and, whilst the human population is small, livestock loads and resultant browsing pressure can be high relative to carrying capacity in this arid region. However, the impact of livestock browsing on this species is currently unknown and so Barleria schenckii is provisionally assessed as Data Deficient — DD. It is unlikely to qualify as “Rare” (sensu Raimondo et al. 2009) as its EOO is significantly greater than 500 km2, but more information is required on its population size and local abundance.
Distribution
Endemic to southwestern Namibia (Karas Region).
Ecology
Barleria schenckii is recorded from dry sandy, gravelly and stony riverbeds and flats, and from amongst boulders and cliff faces on granite and basalt outcrops; elevation is not recorded on herbarium labels, but most of this region is between (550 –) 1050 – 1650 m elevation. It occurs in the Southern Desert and Desert-Dwarf Shrub Transition vegetation types of Mendelsohn et al. (2002) in the transition between the Namib Desert and Nama Karoo biomes. It falls within Craven’s (2009) Southern Succulent Desert floristic group.
Morphology General Habit
Harshly spiny shrublet, 30 – 60 cm tall, cushion-shaped to conical with many branches; stems soon turning woody then whitish or sandy-coloured, angular, with two opposite-decussate bands of short white retrorse hairs
Morphology Leaves
Leaves elliptic to oblong-elliptic, 1 – 2.5 × 0.5 – 0.8 cm (l:w ratio (1.5 –) 2 – 3 (– 3.4):1), base acute or often obtuse, margin white-cartilaginous, sinuate and spinose with (1 –) 3 – 12 spines per side, apex spinose, surface strigulose beneath mainly along the prominent midrib, surface elsewhere minutely puberulent but glabrescent; lateral veins c. 5 pairs, inconspicuous; petiole to 3 mm long
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens inserted 10.5 – 13 mm from base of corolla tube; filaments 17 – 25 mm long; anthers 1.8 – 2.3 mm long; lateral staminodes 2 – 3.5 mm long, pubescent at base, antherodes developed but thecae unequal, larger theca 0.5 – 0.6 mm long
Morphology Reproductive morphology Flowers Calyx
Calyx glaucous-green, paler towards base, or sometimes purplish, can turn whitish or scarious with maturity; anterior lobe narrowly elliptic to lanceolate, 12 – 17 × 5 – 7 mm, base attenuate, margin ± revolute, spinulose with flexuose spines to 1 mm long, apex attenuate-spinose or bispinose, surface sparsely strigose mainly on veins, sometimes also sparsely puberulous; posterior lobe ovate, 17.5 – 22 × 7 – 11 mm, margin usually markedly revolute and can partially envelope anterior lobe, marginal spines sometimes up to 2 mm long, apex long attenuate into a prominent spine, midrib prominent; lateral lobes linear-lanceolate with attenuate apex, 7 – 9.5 mm long
Morphology Reproductive morphology Flowers Corolla
Corolla mauve to bright blue, 32 – 41 mm long, eglandular-pubescent externally; tube cylindrical, narrowly campanulate towards mouth, 22 – 25 mm long; limb subregular; abaxial lobe obovate, 10 – 14 × 6.5 – 9.5 mm, apex obtuse or shortly attenuate; lateral lobes somewhat narrower and can be obovate-elliptic, 5.5 – 8.5 mm wide; adaxial lobes as laterals but 5 – 7.5 mm wide
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary with dense minute crisped white hairs at attachment point of style, with or without sparse straight hairs on surface; style glabrous; stigma linear or clavate, 0.65 – 0.9 mm long
Morphology Reproductive morphology Fruits
Capsule apparently 4-seeded, 9 mm long (?immature), glabrous.
Morphology Reproductive morphology Inflorescences
Inflorescences axillary, contracted unilateral cymes up to 3 cm long, each 2 – 7-flowered; bracts foliaceous; peduncle 1.5 – 5.5 mm long; bracteoles glaucous particularly towards base and margin, tardily turning scarious, pairs unequal, the larger of each pair held erect, broadly lanceolate, 15 – 30 × 5 – 8.5 mm, base usually rounded, truncate or subcordate, often asymmetric, margin spinose with typically 8 – 12 main spines per side, these up to 1.2 – 2.7 mm long, apex long-attenuate into a harsh spine; smaller bracteole of each pair held close to inflorescence axis, linear-lanceolate, surfaces minutely puberulent or glabrescent, midrib prominent
Note
Nyirenda (2012) proposed this taxon as a new species, Barleria bracteilobis Nyirenda, with Theile THE89 as the type specimen. However, she appears to have overlooked the name B. schenckii. Barleria schenckii is closely allied to B. rigida and was previously treated as a variant but it is re-elevated to species status here based on its strikingly broad, glaucous bracteoles with an abruptly narrowed base, the highly unequal outer calyx lobes with ± revolute margins, the entirely eglandular corolla indumentum and the more campanulate corolla throat. It is most likely to be confused with forms of B. rigida subsp. latibracteata with broad bracteoles, which differs in the bracteoles being less abruptly narrowed at the base, in the outer calyx lobes lacking revolute margins and the pair being more equal in size, and in having a corolla indumentum of mixed eglandular and long glandular hairs. Helary & Batault 196 from Wegdraai in Karas (WIND!) appears somewhat intermediate between the two species — it has very broad bracteoles with an abruptly narrowed base as in B. schenckii but the corolla tube is slender and cylindrical throughout and bears some glandular hairs as in B. rigida.
Type
Tiras, fl. 1885, Schinz s.n. [no. 82 listed on Z sheet; Schinz 3 on K sheet] (lectotype Z* [Z000030618], selected here; isolectotype K! [K000794969]). Additional original syntypes: Namibia, “Gross-Namaland”, Aus, date unknown, Schenck 310 (?Z, not located); “Gross-Namaland”, Aus, fl. 1885, Pohle s.n. (Z* [Z000079153]).

Native to:

Namibia

Barleria schenckii Schinz appears in other Kew resources:

First published in Verh. Bot. Vereins Prov. Brandenburg 31: 199 (1890)

Accepted by

  • Darbyshire, I., Tripp, E.A. & Chase, F.M. (2019). A taxonomic revision of Acanthaceae tribe Barlerieae in Angola and Namibia. Part 1 Kew Bulletin 74(5): 1-85. Royal Botanic Gardens, Kew.

Not accepted by

  • Govaerts, R. (1996). World Checklist of Seed Plants 2(1, 2): 1-492. MIM, Deurne. [Cited as Barleria rigida.]

Literature

Kew Bulletin

  • Craven, P. (2009). Phytogeographic study of the Kaokoveld Centre of Endemism. Ph.D. thesis, University of Stellenbosch. http://hdl.handle.net/10019.1/1325
  • Darbyshire, I. (2015). Barleria. In: J. R. Timberlake & E. S. Martins (eds), Flora Zambesiaca. Vol. 8 (6): 37 – 122. Royal Botanic Gardens, Kew.
  • Dinter, K. (1918). Index der aus Deutsch-Südwestafrika bis zum jahre 1917 bekannt gewordenen pflanzenarten. II. Repert. Spec. Nov. Regni Veg. 15: 340 – 355.
  • Klopper, R. R., Chatelain, C., Bänninger, V., Habashi, C., Steyn, H. M., de Wet, B. C., Arnold, T. H., Gautier, L., Smith, G. E. & Spichiger, R. (2006). Checklist of the flowering plants of sub-Saharan Africa. An index of accepted names and synonyms. South African Botanical Diversity Network Report No. 42, SABONET, Pretoria.
  • Mendelsohn, J., Jarvis, A., Roberts, C. & Robertson, T. (2002). Atlas of Namibia. A portrait of the land and its people. Ministry of Environment & Tourism and David Philip, Cape Town.
  • Meyer, P. G. (1957). Beitrag zur Kenntnis der Acanthaceen Südwestafrikas. Mitt. Bot. Staatssamml. München 2: 368 – 385.
  • Meyer, P. G. (1968). 130. Acanthaceae. In H. Merxmüller (ed.), Prodromus einer Flora von Südwestafrika. J. Cramer, Germany.
  • Nyirenda, F. C. (2012). Morphological variation in five related species of Barleria (Acanthaceae). Unpubl. M.Sc. thesis, University of the Witwatersrand, Johannesburg.
  • Obermeyer, A. A. (1933). A revision of the South African species of Barleria. Ann. Transvaal Mus. 15: 123 – 180.
  • Raimondo, D., Von Staden, L., Foden, W., Victor, J. E., Helme, N. A., Turner, R. C., Kamundi, D. A. & Manyama, P. A. (eds) (2009). Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
  • Schinz, H. (1890). Beiträge zur Kenntnis der Flora von Deutsch-Südwest Afrika und der angrenzenden Gebiete. IV. Verh. Bot. Vereins Prov. Brandenburg 31: 177 – 230.
  • Welman, W. G. (2003). Acanthaceae. In: G. Germishuizen & N. L. Meyer (eds), Plants of southern Africa: an annotated checklist. Strelitzia 14: 92 – 106. National Botanical Institute, Pretoria.

Kew Backbone Distributions

  • Darbyshire, I., Tripp, E.A. & Chase, F.M. (2019). A taxonomic revision of Acanthaceae tribe Barlerieae in Angola and Namibia. Part 1 Kew Bulletin 74(5): 1-85. Royal Botanic Gardens, Kew.

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. 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 2021. 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