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This species is accepted, and its native range is NE. Somalia.

[KBu]

Thulin, M., Darbyshire, I. & Banks, H.I. Kew Bull (2011) 66: 601. https://doi.org/10.1007/s12225-012-9323-2

Conservation
Known from a single specimen, this is probably a very local species that may be regarded as Critically Endangered (CR D1) following the categories and criteria of IUCN (2001). However, at present there are no particular threats to the area, which is without roads and has no permanent inhabitants.
Distribution
Chorisochora chascanoides is known only from the type locality, situated in the Cal Miskaat Range in north-eastern Somalia. Cal Miskaat is well known as an area with many narrowly endemic plant species, some examples from different families being Acacia tephrophylla Thulin, Aloe miskatana S. Carter, Cyclamen somalense Thulin & Warfa, Fagonia gypsophilaBeier & Thulin, Haplophyllumsanguineum Thulin, Helianthemum speciosum Thulin, Jatropha miskatensis Thulin, Plocamasomaliensis (Puff) M. Backlund & Thulin, Polygala dasanensis Thulin, Scutellariasomalensis Thulin, and Wellstediarobusta Thulin.
Ecology
Sheltered ravine in crack in limestone cliff; c. 900 m alt.
Morphology General Habit
Shrublet, c. 30 cm tall; young stems terete or somewhat 4-angled, brownish, densely puberulous with short hairs, older stems glabrescent, up to c. 7 mm in diam. Leaves fairly thick and rigid; blade ovate to elliptic, 6 – 11 × 3.5 – 7 mm, rounded at the base, obtuse to subacute at the apex, with revolute margins, 2 – 4 pairs of lateral veins prominent beneath and network of finer veins often also visible, densely puberulous with short hairs on both surfaces; petiole 1 – 2 (– 4) mm long, puberulous
Morphology Reproductive morphology Flowers
Flowers one per bract; pedicel c. 0.5 mm long; bracteoles 2, linear, 3 – 4 mm long, densely pubescent, caducous
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 2, ± parallel, held ± equidistant between upper and lower lip; filaments attached at the apex of the corolla tube, c. 5 mm long, with short downwardly directed hairs; anthers bithecous, medifixed, c. 2 mm long, thecae oblong and attached at the same height, rounded at both ends; staminodes absent
Morphology Reproductive morphology Flowers Calyx
Calyx divided almost to the base; lobes 5, linear, 4 lobes subequal and 5 – 6.5 mm long, the ventral lobe 3 – 3.5 mm long, all densely pubescent with spreading eglandular and glandular hairs
Morphology Reproductive morphology Flowers Corolla
Corolla 2-lipped, probably magenta, pubescent outside; tube c. 4 mm long, c. 1.5 mm wide, cylindrical, slightly curved; lobes c. 5 mm long, becoming recoiled at anthesis; upper lip linear, of 2 fused lobes, entire; lower lip deeply divided into 3 linear lobes
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary 4-ovulate, pubescent; style filiform, c. 9 mm long, pubescent in lower part; stigma minutely bilobed
Morphology Reproductive morphology Fruits
Capsule club-shaped, flattened, c. 9 × 3 – 4 mm, pubescent, 2 – 3-seeded
Morphology Reproductive morphology Inflorescences
Inflorescence raceme-like, 3 – 13.5 cm long including up to 0.8 cm long peduncle; axis pubescent with spreading eglandular and glandular hairs; bracts narrowly ovate to obovate, 3.5 – 4 mm long, densely pubescent with short and long spreading hairs on both surfaces, subacute, with obscure venation, caducous
Morphology Reproductive morphology Seeds
Seeds flattened, broadly elliptic in outline, c. 4 – 4.5 × 3 mm, shortly spinulose all over and with a verrucose rim.
Note

In the key to the genera of the Ecbolium group presented by Vollesen (1994), Chorisochora is distinguished from EcboliumKurz (22 species in the Old World), Megalochlamys Lindau (10 species in Africa and Arabia) and TrichaulaxVollesen (one species in Kenya and Tanzania) by having pedicellate flowers and corolla lobes longer than or about as long as the tube, and from AngkalanthusBalf. f. (one species on Socotra) by having erect inflorescences, linear-lanceolate calyx lobes, a more or less cylindrical corolla tube, a deeply lobed lower lip of the corolla, and by having stamens held more or less equidistant between the corolla lips. The new Somali species fits the generic description of Chorisochora in all these respects, although the pedicels are only about 0.5 mm long (versus 1 – 2 mm in the three other species).

The genus Chorisochora was described by Vollesen (1994) to accommodate three species, C. striata (Balf. f.) Vollesen (previously Ecbolium striatum Balf. f.), C. minor (Balf. f.) Vollesen (previously E. striatum var. minor Balf. f.), and C. transvaalensis (Meeuse) Vollesen (previously AngkalanthustransvaalensisMeeuse). C. striata and C. minor are confined to Socotra, whereas C. transvaalensis, the type of the genus, is confined to NE South Africa and Botswana.

The epithet chascanoides chosen for the new species refers to its habit, which is superficially similar to various species of Chascanum E. Mey. (Verbenaceae), also found in rocky habitats in northern Somalia.

According to Vollesen (1994) the pollen morphology of Angkalanthus and of the three species of Chorisochora then known is essentially identical to the Ecbolium-type of pollen as described by Furness (1989). The pollen morphology of the new species described here is also of the Ecbolium-type and does not contradict the placement of this species in the genus Chorisochora . It is of note that the genera Megalochlamys (Furness 1989) and Trichaulax (Furness 1992) differ markedly in their pollen morphology.

Chorisochora chascanoides seems to be most closely related to its geographical neighbours, C. striata and C. minor on Socotra. These three species all differ markedly from C. transvaalensis in southern Africa by having corolla lobes only slightly longer than the tube (not about twice as long as the tube), flowers in unbranched raceme-like inflorescences (not in branched paniculate inflorescences), and by their small capsules (8 – 13 mm vs 15 – 22 mm long). However, C. chascanoides clearly differs from both C. striata and C. minor by its densely puberulous (not glabrous) stems and leaves. Furthermore, C. chascanoides differs from all the other species in the genus by its revolute leaf margins and small flowers (corolla tube c. 4 mm vs 6 – 18 mm long and corolla lobes c. 5 mm vs 10 – 25 mm long).

Daniel et al. (2008) included Chorisochora , together with sampling of members of Angkalanthus, Ecbolium, Megalochlamys and Trichaulax, in a molecular study focusing mainly on the New World “Tetramerium lineage”. However, the position of Chorisochora , represented only by C. transvaalensis, was unresolved in relation to these genera. Daniel et al. (2008) concluded that “it is clear that understanding of Chorisochora requires inclusion of the Socotran species in phylogenetic work”. Pending this, we here accept the genus with its original circumscription.

Native to:

Somalia

Chorisochora chascanoides Thulin & I.Darbysh. appears in other Kew resources:

First published in Kew Bull. 66: 601 (2012)

Accepted by

  • Govaerts, R., Nic Lughadha, E., Black, N., Turner, R. & Paton, A. (2021). The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. https://doi.org/10.1038/s41597-021-00997-6 Scientific Data 8: 215.

Literature

Kew Bulletin

  • Daniel, T. F., McDade, L. A., Manktelow, M. & Kiel, C. A. (2008). The “Tetramerium lineage” (Acanthaceae: Acanthoideae: Jusiticieae): delimitation and intra-lineage relationships based on cp and nrITS sequence data. Syst. Bot. 33: 416 – 436.CrossRefGoogle Scholar
  • Furness, C. A. (1989). The pollen morphology of Ecbolium and Megalochlamys (Acanthaceae). Kew Bull. 44: 681 – 693.CrossRefGoogle Scholar
  • Furness, C. A. (1992). A note on the pollen of Trichaulaxmwasumbii (Acanthaceae: Justicieae). Kew Bull. 47: 619 – 624.CrossRefGoogle Scholar
  • Hedrén, M. & Thulin, M. (2006). Acanthaceae. In: M. Thulin (ed.), Flora of Somalia 3: 374 – 454. Royal Botanic Gardens, Kew.
  • IUCN (2001). IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland & Cambridge, UK.
  • Punt, W., Blackmore, S., Nilsson, S. & Le Thomas, A. (1994). Glossary of Pollen and Spore Terminology. LPP Contrib. Ser. 1. LPP Foundation, Utrecht University.
  • Vollesen, K. (1994). Delimitation of Angkalanthus (Acanthaceae: Justicieae) and the new genus Chorisochora. Kew Bull. 49: 469 – 479.CrossRefGoogle Scholar

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