Ensermu & Darbyshire. 2018. Six new species of Barleria L. (Acanthaceae) from Northeast Tropical Africa. Kew Bulletin 73:1. DOI 10.1007/S12225-017-9725-2
- This species is currently known only from central and southern Somalia along the Shebelle River catchment, with an EOO of 18,634 km2 which falls within the “Vulnerable” range threshold under IUCN criterion B1. It has been recorded as locally common by several collectors. Some of the collecting sites had been impacted by shifting cultivation or by removal of larger woody species for fuelwood at the time of collection but this does not appear to have negatively impacted this species. That said, study of Google Earth imagery indicates that there has also been significant conversion of natural vegetation to more intensive agricultural land in some parts of its range along the Shebelle, particularly in the Janalle area west-southwest of Mogadishu. This will very likely have led to some population declines in that area. There is also considerable pressure on the water resources of the Shebelle both in Ethiopia and Somalia, with future water demands projected to increase markedly (Michalscheck et al.2016). These long-term changes to water levels may impact the vegetation of the surrounding catchment. The Shebelle-Juba Catchments Freshwater Ecoregion has been assessed as Vulnerable by Thieme et al. (2005), citing growing agricultural pressure and human population growth as the most likely threats, although they acknowledge that limited information is available on its curent status. With less than 10 locations known and with inferred decline in extent and quality of habitat, this species is therefore provisionally assessed as Vulnerable VU B1ab(iii),al- though with more information desirable on its current range and abundance.
- Barleria shebelleensis is restricted to central and southern Somalia (Flora of Somalia regions C2, S2 and S3), along the lower catchment of the Shebelle River. It may also occur along the southeastern Ethiopian portion of that river which forms the border between Harar and Bale Floristic regions. Map 1, red circles.
- This species is recorded from the ground layer of open woodland and scrub usually on alluvial clay or silt plains, with variously Acacia nilotica (L.) Delile, Acacia oerfota (Forssk.) Schweinf., Acacia zanzibarica (S. Moore) Taub., Balanites aegyptiaca (L.) Delile, Blepharispermum fruticosum Klatt, Cordia sinensis Lam. and/or Dalbergia commiphoroides Baker f. in the shrub or tree layer. It grows at 25 - 200 m elevation.
- Morphology General Habit
- Woody-based perennial herb or shrublet; stems erect to trailing-decumbent, 5 - 40 (?- 100) cm high, much branched, 4-angular when mature with 4 narrow ± conspicuous furrows that have a more dense white indumentum than the rest of the stem, this pubescent with white appressed medifixed and retrorse hairs, often densely so, interspersed with some patent glandular hairs on distal internodes; internodes 3 - 6 cm long. $ Leaves subsessile, blade bluish-green, oblong-elliptic to oblong-lanceolate, 13 - 62 x 5 - 14 mm, base obtuse or rounded, margin entire, apex acute to rounded and mucronate, surfaces with appressed long medifixed hairs on both surfaces, distal leaves with spreading glandular hairs beneath towards the margins, young leaves can also be finely puberulent; lateral veins very faint, 3 - 4 pairs
- Morphology Reproductive morphology Flowers Androecium Stamens
- Stamens inserted 3 - 5.5 mm above base of corolla tube, filaments 8 - 16 mm long, glabrous; anthers 1.8 - 2.8 mm long; staminodes 3, lateral staminodes 0.3 - 1 mm long, antherodes lacking
- Morphology Reproductive morphology Flowers Calyx
- Calyx with lobes very unequal, anterior lobe linear-lanceolate, 4.5 - 8.7 x 1 - 1.5 mm, widest at base, apex entire or sometimes bifid; posterior lobe much larger, oblong-oblanceolate, 9 - 15.5 x 1.5 - 3.3 mm, widest in distal third, apex acute or attenuate; both lobes with short spreading glandular hairs and long appressed anvil-shaped biramous hairs, or these simple along lobe margins, surfaces can also be white eglandular- puberulous; lateral lobes linear-lanceolate, 4 - 6 x 0.7 - 1 mm
- Morphology Reproductive morphology Flowers Corolla
- Corolla white, with (or ?without) pink streaks in the throat, 18 - 27 mm long, eglandular-puberulous externally on distal portion of tube and on limb with or without few interspersed glandular hairs; tube 11.5 - 15.5 mm long, proximal portion ± 1.5 - 2 mm wide, throat gradually funnel-shaped, to 3.7 - 5.5 mm wide at mouth; limb in “4+1 ” configuration; abaxial lobe offset by 1.8 - 3.3 mm, broadly obovate, 5.5 - 10.5 x 4.7 - 8.8 mm, apex rounded or truncate; lateral lobes obovate-orbicular, 4 - 8.5 x 3.5 - 7.5 mm, apices rounded, adaxial lobes obovate or obovate-elliptic, 3.5 - 7.5 x 2.8 - 5.5 mm
- Morphology Reproductive morphology Flowers Gynoecium Ovary
- Ovary ± 2.5 mm long, puberulous with ascending hairs; style 14 - 16 mm long, glabrous or pubescent at base; stigma linear, 1 - 1.2 mm long
- Morphology Reproductive morphology Fruits
- Capsule 8.5 - 11.5 x 3.5 - 4mm,eglandular- puberulous; seeds 3 - 4 x 2.6 - 3.8 mm, ovate in face view, covered with curled cream-coloured hygroscopic hairs
- Morphology Reproductive morphology Inflorescences
- Inflorescences axillary, cymes bearing 1 - 3 flowers; peduncle 1 - 4.5 mm long, hairs as stems; bracteoles foliaceous, oblong-elliptic or those of lateral flowers more oblanceolate, 8 22 x 2 - 9 mm, often oblique towards the mucronate apex, pubescent with medifixed hairs and patent glandular hairs, larger pairs tripliveined; pedicels 1.5 - 4.5 mm long
- Barleria shebelleensis falls within the B. argentea Balf. f. - B. parvifl ora T. Anderson complex but is easily separated from all other species in that group by having markedly dimorphic outer calyx lobes, the anterior lobe being linear-lanceolate and only marginally larger and wider than the lateral lobes whilst the posterior lobe is considerably larger (often twice as long) and oblong-oblanceolate in shape. The markedly 4-angular stems with ± conspicuous furrows at each angle also separate this species from its closest allies. B. shebelleensis is morphologically most similar to B. parvifl ora T. Anderson from which it differs in having 1 - 3-flowered cymes (flowers always solitary in B. parvifl ora) with a ± well-developed pedicel 1.5 – 4.5 mm long and bracteoles that are foliaceous and ± markedly larger than the calyx lobes and dissimilar in shape (in B. parvifl ora the flowers are sessile, immediately subtended by the bracteoles which are held erect, partially enveloping the calyx and ± closely resembling the outer calyx lobes in shape and size), and a puberulous ovary and capsule (glabrous in B. parvifl ora). Further, the peduncle of B. parvifl ora is often much longer than in B. shebelleensis, typically 5 - 20 (- 25) mm long, and the outer calyx lobes of B. parvifl ora are not dimorphic, both being ovate to oblong-lanceolate. Barleria shebelleensis has previously been included within B. hochstetteri Nees with which it is vegetatively similar but it is easily separated from that species by the very different calyx, the outer lobes both being ovate to oblong-lanceolate in B. hochstetteri; the more contracted inflorescences, B. hochstetteri having peduncles 8 - 25 (- 38) mm long and pedicels 5 - 15 (- 27) mm long; and the less markedly zygomorphic corolla with the abaxial lobe only being offset by up to 3.3 mm (vs 4.5 - 7mm in B. hochstetteri). On Kuchar 17046, this species is recorded as a “dwarf shrub to 1m” but on the three sheets of that collection at K, the specimens are less than 40 cm tall in keeping with all other material seen, hence the maximum height is recorded as “?- 100 cm” in the description. Barleria shebelleensis is named after the Shebelle River, as this species is closely associated with the catchment of this major river. The combination of a prominently beaked, 2- seeded capsule, seeds with wavy hygroscopic hairs, an androecium comprising two fertile stamens and three minute staminodes and the plants lacking spines place Barleria shebelleensis in sect. Somalia (Oliv.) Lindau (Balkwill & Balkwill 1997; Darbyshire2009). This species also has medifixed hairs on the vegetative parts, bluish-green foliage and corollas which are (at least sometimes) streaked in the throat, characters that together place this species in Balkwill's(1993) “Group 1” of sect. Somalia which contains the Barleria argentea- parviflora complex. This group is challenging taxonomically, containing a number of closely allied species in NE Africa and Arabia that are usually separable by a range of morphological characters but with occasional intermediates suggesting that hybridisation is not uncommon (see discussion in Darbyshire2010: 407). This complex is in need of detailed taxonomic study, combining molecular and morphological analyses. That said, B. shebelleensis is one of the most easily recognisable and discrete members of this complex in view of its unique calyx configuration in which the anterior lobe is more similar to the lateral lobes than it is to the markedly enlarged posterior lobe. It also has a less markedly zygomorphic corolla than other members of this complex, as the abaxial lobe is only shortly offset. M. Hedren had annotated the folders of this species at K with the provisional name “kuchari” but in the Flora of Somalia account (Hedren2006a)he treated it as a form of Barleria hochstetteri noting it as “a fairly distinct form...similar to B. argenteain its narrow calyx lobes, but has an upright shrubby growth and agrees with B. hochstetteri in the large and wide leaves and more evenly dispersed hairs, as well as spreading thin hairs” (p. 436). Hedren did not include Virgo 40 and Alstrup & Michelsen 66 within this form, listing these separately as specimens of B. hochstetteri tending towards B. argentea. However, these two specimens clearly belong to the same taxon as the rest of the material cited above. He appears to have missed the fact that the anterior and posterior calyx lobes are markedly dimorphic in this species.
First published in Kew Bull. 73(1)-1: 19 (2018 publ. 2017)
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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 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