Asteraceae

Lactuca L.

First published in Sp. Pl.: 795 (1753)
This genus is accepted
The native range of this genus is Old World, N. America to Guatemala, Bahamas, Hispaniola.

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, biennial or (not in Iraq) perennial herbs
Morphology Stem
Stems scapose or leafy, glabrous or with spreading or deflexed bristles
Morphology Leaves
Leaves simple or lobed or runcinate-pinnatisect, base often sagittate and occasionally decurrent
Morphology Reproductive morphology Inflorescences
Inflorescence a spike or panicle of erect capitula
Morphology Reproductive morphology Inflorescences Bracts Involucre
Involucre cylindrical; phyllaries multiseriate, gradate, imbricate; receptacle naked
Ray
Ray florets yellow or blue, c. 2× as long as tube
Morphology Reproductive morphology Fruits
Achenes ± compessed, beak shorter to much longer than body, terminating in a disc which bears pappus and floral remains; pappus setae uniseriate, smooth or barbellate, white, wholly deciduous from disc.
Distribution
About 60 species, in dry habitats and those with a moderate water supply in the northern hemisphere and Africa; 10 species in Iraq.
Etymology
Lactuca (from Gr. γαλακτικό, galactico, having milk).
[FIQ]

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

Morphology General Habit
Herbs or subshrubs, with white latex
Morphology Leaves
Leaves alternate
Morphology Reproductive morphology Inflorescences
Capitula often in paniculate inflorescences; involucre cylindrical; receptacle naked
Morphology Reproductive morphology Fruits
Achenes flattened, distinctly beaked, usually with ribs; pappus of smooth or scabrid bristles.
Distribution
Over 100 species in Europe, Asia, Africa and North America, one widely cultivated.
[FSOM]

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

Morphology General Habit
Annual or perennial herbs or subshrubs, rarely scandent
Morphology Leaves
Leaves alternate or in a rosette, variable from entire to pinnatisect, often spinulose, sometimes reduced
Morphology Reproductive morphology Inflorescences Capitulum
Capitula in various inflorescences, generally corymbose or paniculate; phyllaries unequal, in several series, the outermost smallest; receptacle epaleate, with ± fimbriate alveolae
Morphology Reproductive morphology Flowers Florets
Florets with anthers sagittate at base, auricles acute or shortly setaceous-acuminate; style branches long with conspicuous sweeping hairs
Morphology Reproductive morphology Fruits
Achenes lengthening after anthesis, flattened, usually ribbed, generally with a distinct beak; pappus of bristles.
[FTEA]

Compositae, G. V. Pope. Flora Zambesiaca 6:1. 1992

Morphology General Habit
Annual, perennial or biennial herbs, erect often scapigerous, sometimes scandent.
Morphology Stem
Stems mostly solitary and branched above, glabrous, crispate-pubescent or setulose, rarely spinescent.
Morphology Leaves
Leaves radical, or cauline and alternate, often auriculate-amplexicaul, undivided to deeply runcinate-pinnatisect, or rarely pinnately compound, margins entire or remotely denticulate to coarsely dentate, glabrous or crispate-pubescent to setulose, rarely spinose-setose on midribs beneath, often glaucous.
Morphology Reproductive morphology Inflorescences Capitulum
Capitula few to numerous, corymbose or thyrsoid-paniculate, sometimes solitary.
Morphology Reproductive morphology Inflorescences Bracts Phyllaries
Phyllaries 3–5-seriate, elongating in the fruiting stage.
Morphology Reproductive morphology Flowers Receptacle
Receptacle epaleate, alveolate; alveolae ± fimbriate.
Morphology Reproductive morphology Flowers Corolla
Corollas yellow whitish purplish or blue.
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anthers sagittate at the base, auricles acute or shortly setaceous-acuminate.
Morphology Reproductive morphology Flowers Gynoecium Style
Style branches long with conspicuous sweeping hairs.
Morphology Reproductive morphology Fruits
Achenes homomorphic, ± ellipsoidal, ± compressed, apex constricted and produced as a distinct filamentous beak, or beak absent; achene body ribbed, minutely rugose-scabridulous, ascending-hispidulous; pappus several-seriate of uniform white or straw-coloured, barbellate setae, rarely with an outer ring of minute setae.
[FZ]

Sources

  • Flora Zambesiaca

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

  • 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

  • Herbarium Catalogue Specimens

  • 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