Asteraceae

Xanthium L.

First published in Sp. Pl.: 987 (1753)
This genus is accepted
The native range of this genus is New World, NW. Africa, Europe to China and Indo-China, Taiwan.

Descriptions

Ghazanfar, S. A., Edmondson, J. R. & Hind, D. J. N. (Eds). (2019). Flora of Iraq, Volume 6: Compositae.Kew Publishing

Morphology General Habit
Annual herbs
Morphology Leaves
Leaves alternate, entire or lobed
Morphology Reproductive morphology Inflorescences
Inflorescence terminal and axillary
Morphology Reproductive morphology Inflorescences Capitulum
Capitula unisexual, monoecious, solitary or in clusters Female capitula few at base of inflorescence, ovoid, 2-flowered, 2-locular, densely armed with hooked or straight spines and bearing 2 apical beaks; corolla absent; stamens absent; style persistent, bifid, exerted from hole on inner face of beak Male capitula terminal, many- flowered; phyllaries free, uniseriate; receptacle scaly
Morphology Reproductive morphology Flowers Corolla
Corolla greenish, tubular, regular, 5-dentate; filaments monadelphous; anthers free, exserted, sagittate, minutely appendiculate; gynoecium imperfect, style undivided
Morphology Reproductive morphology Fruits
Fruit an indehiscent burr; seed glabrous with styles persisting at apex; pappus absent.
Distribution
A genus of possibly 3 species, probably originating in America, 2 species now of almost world-wide distribution; 2 species in Iraq.
Etymology
Xanthium (from Gr. ξανθος (xanthos), yellow or fair-haired, doubtless a reference to the colour of the spines. Two goddesses were named Xanthe, ‘the golden one’, in Gr. mythology (one was a Naiad, daughter of Oceanus, the other an Amazon).
[FIQ]

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

Morphology General Habit
Coarse herbs, often spiny
Morphology Leaves
Leaves alternate
Morphology Reproductive morphology Inflorescences Capitulum
Capitula unisexual, male on short axillary branches and several-flowered, female axillary, subsessile and beneath the male, 2-flowered
Morphology Reproductive morphology Flowers Florets
Male florets with corolla 5‑lobed, cylindric; anthers black
Morphology Reproductive morphology Inflorescences Bracts Involucre
Involucre in female capitula fused to a spiny extended receptacle, enclosing the 2 florets, with 2 long beaked spines, female florets without corolla, the style 2-fid; achenes black, pappus absent
Distribution
Two (or more) species in Central and/or South America, but now troublesome weeds in all continents.
[FSOM]

Compositae, H. Beentje, C. Jeffrey & D.J.N. Hind. Flora of Tropical East Africa. 2005

Morphology General Habit
Annual herbs
Morphology Leaves
Leaves alternate
Morphology Reproductive morphology Inflorescences Capitulum
Capitula unisexual, monoecious, axillary or terminal, discoid
sex Male
Male capitula globose, many-flowered; involucre with few phyllaries; receptacle paleate; corolla subcylindric, 5-dentate; anthers with minute apical appendage; style undivided
Morphology Reproductive morphology Flowers
Female capitula beneath the male, 2-flowered; involucre connate, 2-beaked at apex and covered with hooked bristles; corolla absent; style bifid Male capitula globose, many-flowered; involucre with few phyllaries; receptacle paleate; corolla subcylindric, 5-dentate; anthers with minute apical appendage; style undivided
sex Female
Female capitula beneath the male, 2-flowered; involucre connate, 2-beaked at apex and covered with hooked bristles; corolla absent; style bifid
Morphology Reproductive morphology Fruits
Achenes enclosed in the hardened involucre; pappus absent.
[FTEA]

Sources

  • Flora of Iraq

    • Flora of Somalia
    • 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

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • World Checklist of Vascular plants (WCVP)

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0