2118.000 Thesium L.

Description of the genus

Annual or perennial herbs or subshrubs, parasitic or hemiparasitic. Leaves sessile, alternate, scale-like or ± linear. Flowers bisexual, solitary or in cymes, each flower subtended by 1, often conspicuous, bract which is often adnate to the pedicel or peduncle and 2 bracteoles or (in T. atrum and T. fastigiatum) by an involucre of 4 or more bracts. Perianth (3-4-)5-lobed, often with conspicuous external glands on the perianth tube below the sinuses of the lobes. Stamens as many as lobes; anthers (in ours) attached to lobes by tufts of hairs. Ovary with 3 ovules. Stigma capitate. Fruit a nut, rarely fleshy, usually 10-ribbed, crowned with the persistent perianth.

Comment: A very difficult genus to identify in the field at species level. Almost all distinguishing features are based on measurements or characteristics of minute parts, which can only be seen and compared reliably under a microscope.

Worldwide: 325 species in the Old World

Zimbabwe: 24 taxa.

Insects associated with this genus:
Eicochrysops messapus (Cupreous blue) Larval food plant
Thesium nigricans

Links to taxa:     View: living plant images - herbarium specimen images - all images for this genus

SpeciesFZ divisionsContent
asterias A.W. HillE
atrum A.W. HillN,C
brevibarbatum Pilg.N,W,C,EDescription
breyeri N.E. Br.C
bundiense Hilliard[NrEnd][LR-nt]E
chimanimaniense Brenan[NrEnd][LR-nt]E
cymosum A.W.HillN,E,S
dissitum N.E.Br.N,W,C
dolichomeres Brenan[NrEnd][LR-nt]EDescription, Image
fastigiatum A.W. HillN,CDescription, Image
goetzeanum Engl.N,W,C,EDescription, Image
gracile A.W. HillW,C,E,S
helodes HilliardN,C
magnifructum HilliardN,W
megalocarpum A.W. HillW,C
multiramulosum Pilg.C,E
myriocladum BakerW
nigricans RendleEDescription, Image
pygmaeum Hilliard[NrEnd]EDescription, Image
subaphyllum Engl.N
thamnus Robyns & LawalréeN
unyikense Engl.N
ussanguense Engl.E
whyteanum RendleEImage

Other sources of information about Thesium:

Our websites:

Flora of Botswana: Thesium
Flora of Malawi: Thesium
Flora of Mozambique: Thesium
Flora of Zambia: Thesium

External websites:

ePIC (electronic Plant Information Center): Thesium
Flora Zambesiaca web site: Thesium
Google: Web - Images - Scholar
GRIN (Germplasm Resources Information Network) taxonomy for plants report for Thesium
Wikipedia: Thesium
IPNI (International Plant Names Index): Thesium
Kew Herbarium catalogue: Thesium

Copyright: Mark Hyde, Bart Wursten, Petra Ballings and Meg Coates Palgrave, 2002-22

Hyde, M.A., Wursten, B.T., Ballings, P. & Coates Palgrave, M. (2022). Flora of Zimbabwe: Genus page: Thesium.
https://www.zimbabweflora.co.zw/speciesdata/genus.php?genus_id=504, retrieved 29 November 2022

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