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This genus is accepted, and its native range is Tropical & S. Africa, SW. Arabian Peninsula.

[O-EM]
General Description

Terrestrial herbs with small, ovoid or ellipsoid tubers. Leaves radical, 1-2, appressed to ground, sessile, ovate or orbicular, sometimes withered by flowering time. Inflorescence erect, unbranched, with or without sheaths, sparsely to densely flowered. Flowers sessile or shortly stalked, often secund. Sepals subegual, free, sometimes setose, often hairy, usually green. Petals usually longer (often much longer) than sepals, entire or lobed, often rather fleshy. Labellum lobed or toothed, rarely entire, spurred; adnate to column at base. Column short; anther loculi parallel; pollinia two, granular; caudicles short; viscidia mall, naked; stigma sessile. (PC).

Distribution

A genus of 50-60 species in tropical Africa, South Africa, and tropical Arabia. (PC).

Ecology

Members of the terrestrial genus Holothrix grow in a variety of habitats across its range in both exposed and shaded conditions. For example, the distribution of the 25 Holothrix species from South Africa encompasses the semi-arid regions of the Karoo and Namaqualand and the winter-rainfall area of the south-western Cape Province, to the forests and grasslands in the summer-rainfall areas of the eastern Cape Province, Natal, and the Transvaal (Schelpe 1966). In other areas such as Zambia, Malawi, and Tanzania, Holothrix is typically found in Brachystegia (Fabaceae) woodland and in dry grassland in the submontane or montane zones at elevations ranging from 1300-2300 m, where it often appears after the grass has been burned (la Croix and Cribb 1995). Plants are frequently located near boulders or among rocky areas that offer some shade or are sites of water seepage. In southern Africa H. orthoceras Rchb.f. is said to be often found among moss-covered rocks, H. macowania Rchb.f. in shallow soils near granite boulders, and H. johnstonii Rolfe and H. longiflora Rolfe on slabs of rock and in crevices in seepage slopes (la Croix and Cribb 1995). In Saudi Arabia, H. arachnoidea Rchb.f., which is widespread along the escarpment in the Asir and southern Hijaz, always occurs in shade, including the shade of boulders (Collenette 1985).
The main flowering season for Holothrix is the spring and summer. Prior to flowering, the slender stem and pair of leaves that typically lie flat to the ground arise from the small ovoid or ellipsoid underground tubers. Although the leaves usually do not senesce before the flowers open, this does occur in some species such as H. thodei Rolfe (Schelpe 1966). The formation of fruits in Holothrix has been recorded from some herbarium specimens collected from southern Africa (la Croix and Cribb 1995). (RN).

[FZ]

Orchidaceae, I. la Croix & P.J. Cribb. Flora Zambesiaca 11:1. 1995

Morphology General Habit
Terrestrial herb with small ovoid or ellipsoid tubers.
Morphology Leaves
Leaves radical, 1–2, appressed to ground, sessile, ovate or orbicular, sometimes withered by flowering time.
Morphology Reproductive morphology Inflorescences Scape
Scape erect, unbranched, with or without sheaths.
Morphology Reproductive morphology Flowers
Flowers sessile or shortly stalked, often secund.
Morphology Reproductive morphology Flowers Calyx
Sepals subequal, free, often hairy, usually green.
Morphology Reproductive morphology Flowers Corolla
Petals usually longer (often much longer) than sepals, entire or lobed, often rather fleshy.
Morphology Reproductive morphology Flowers Labellum
Lip lobed or toothed, rarely entire, spurred; adnate to column at base.
Morphology Reproductive morphology Flowers Column
Column very short; anther loculi parallel, pollinia granular; caudicles very short, viscidia small, naked; stigma sessile.

[FTEA]

Orchidaceae, V. S. Summerhayes. Flora of Tropical East Africa. 1968

Morphology General Habit
Terrestrial herbs with small ovoid or ellipsoid tubers and 1 or 2 sessile ovate or orbicular radical leaves
Morphology Reproductive morphology Inflorescences Scape
Scape erect, with or without sheaths, unbranched
Morphology Reproductive morphology Flowers
Flowers often secund, sessile or shortly stalked
Morphology Reproductive morphology Flowers Calyx
Sepals subequal, free from one another, often hairy, thin in texture
Morphology Reproductive morphology Flowers Corolla
Petals usually longer (often much longer) than sepals, entire or divided in the upper part into 3 or more finger-like lobes, rather fleshy
Morphology Reproductive morphology Flowers Labellum
Lip similar to petals but broader with more lobes, spurred at the base, adnate to the column
Morphology Reproductive morphology Flowers Column
Column very short; anther-loculi parallel, pollinia granular, caudicles very short, viscidia small, naked; stigma sessile.

[FSOM]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Terrestrial herbs with small ovoid root tubers and 1 or 2 sessile ovate to orbicular radical leaves
Morphology Reproductive morphology Inflorescences Scape
Scape an erect raceme with sessile or shortly stalked and often secund flowers
Morphology Reproductive morphology Flowers Calyx
Sepals entire
Morphology Reproductive morphology Flowers Corolla
Lip similar to lateral petals but broader with more lobes and spurred at base Lateral petals entire or divided into 3 to many lobes
Morphology Reproductive morphology Flowers Column
Column very short with 2 sectile pollinia.
Distribution
About 45 species in tropical and subtropical Africa with two species extending to Arabia.

Native to:

Angola, Burundi, Cameroon, Cape Provinces, Djibouti, Eritrea, Ethiopia, Free State, Kenya, KwaZulu-Natal, Lesotho, Malawi, Mozambique, Namibia, Nigeria, Northern Provinces, Rwanda, Réunion, Saudi Arabia, Socotra, Somalia, Sudan, Tanzania, Uganda, Yemen, Zambia, Zaïre, Zimbabwe

Holothrix Rich. ex Lindl. appears in other Kew resources:

Date Reference Identified As Barcode Type Status
Williamson, G. [395], Malawi 32561.000
Burchell [6369] K000364258

First published in Gen. Sp. Orchid. Pl.: 257 (1835)

Accepted by

  • Govaerts, R. (2003). World Checklist of Monocotyledons Database in ACCESS: 1-71827. The Board of Trustees of the Royal Botanic Gardens, Kew.
  • Pridgeon, A.M., Cribb, P.J., Chase, M.C. & Rasmussen, F.N. (2001). Orchidoideae (Part 1) Genera Orchidacearum 2: 1-416. Oxford University Press, New York, Oxford.

Literature

Flora of West Tropical Africa

  • F.T.A. 7: 190. Nom. cons.
  • Gen. & Sp. Orch. Pl. 257, 283 (1835)

Flora Zambesiaca

  • Gen. Sp. Orchid. Pl.: 257, 283 (1835), nom. conserv.

Flora of Somalia

  • Flora Somalia, Vol 4, (1995) Author: by B. Pettersson [updated by M. Thulin 2008]

Flora of Tropical East Africa

  • Gen. & Sp, Oreh. Pl.: 257, 283 (1835), nom. conserv,

Flora Zambesiaca
Flora Zambesiaca
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Somalia
Flora of Somalia
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Herbarium Catalogue Specimens
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 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

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