Apiaceae

Sium L.

First published in Sp. Pl.: 251 (1753)
This genus is accepted
The native range of this genus is Temp. Northern Hemisphere.

Descriptions

Ghazanfar, S. A. & Edmondson, J. R (Eds). (2014) Flora of Iraq, Volume 5 Part 2: Lythraceae to Campanulaceae.

Morphology General Habit
Glabrous perennial herbs growing in colonies in wet or damp places, very rarely in dry situations, the lower leaves often submerged and variously pinnatifid into narrow segments; aerial leaves simply pinnate with broad, toothed segments
Morphology Reproductive morphology Inflorescences
Umbels compound, lateral or terminal-Involucre and involucel present, of many bracts
Morphology Reproductive morphology Flowers
Flowers hermaphrodite, white, the petals broadly obovate-rotund or obcordate, retuse or emarginate above with an inflexed lobule
Morphology Reproductive morphology Flowers Calyx
Calyx present, of 5 minute to ± conspicuous sepals
Morphology Reproductive morphology Fruits
Fruit globular-ovoid to oblong, slightly compressed laterally, commissure narrow. Primary ribs 5, obtuse or thickened, conspicuous, the lateral marginal; all narrower than the 1–3-vittate valleculae
Morphology Reproductive morphology Flowers Gynoecium Stylopodium
Stylopodia stout, depressed-conic, margin of the disk entire or crenate
Morphology Reproductive morphology Flowers Carpophore
Carpophore bipartite, adnate or free, or entire
Morphology Reproductive morphology Seeds Endosperm
Endosperm convex, the commissural face flat.
Distribution
10–15 species, almost cosmopolitan, not in Australia or S America; one species in Iraq.
Note
Sium (a name thought by some to have been derived from the Celtic word siu, water, alluding to the aquatic habitat of the species; but considered by most authors to have derived from the Greek σιον, sion, the name for an umbellifer used by Dioscorides and others); Water Parsnip.
[FIQ]

Umbelliferae, J. F. M. Cannon. Flora Zambesiaca 4. 1978

Morphology General Habit
Robust glabrous herbs with pinnate leaves.
Morphology Reproductive morphology Flowers
Flowers all hermaphrodite, in terminal and lateral compound umbels; bracts and bracteoles numerous and conspicuous.
Morphology Reproductive morphology Flowers Calyx
Sepals well developed to minute.
Morphology Reproductive morphology Flowers Corolla
Petals white to yellowish, more or less equal, relatively broad with an incurved apex, rarely the outer becoming subradiate.
Morphology Reproductive morphology Fruits
Fruit ovoid-cylindrical to globose, slightly compressed laterally and constricted at the commissure.
Morphology Reproductive morphology Flowers Gynoecium Stylopodium
Stylopodium conical or sometimes depressed; styles short and stiff, divergent.
Morphology Reproductive morphology Seeds
Ribs filiform, fairly prominent, lateral ribs marginal; mericarps sub-pentagonal in section, endosperm similar.
Morphology Reproductive morphology Flowers Carpophore
Carpophore entire or 2-partite at the apex.
Morphology Reproductive morphology Fruits Vittae
Vittae superficial, 1–6 in each interval and 2–6 in the commissural face.
[FZ]

Umbelliferae, C.C. Townsend. Flora of Tropical East Africa. 1989

Morphology Reproductive morphology Fruits
Fruit glabrous, slightly laterally compressed, broadly ovoid to oblong, not or slightly narrowed to the commissure; primary ribs pale and prominent, narrow; vittae large to rather small, 1–3 in the valleculae, 2–6 on the commissure, visible in surface view or not, pericarp not very spongy; stylopodia shortly conical to rounded, styles short; carpophore undivided to shortly bipartite, adnate to the mericarps or not
Morphology Reproductive morphology Seeds
Endosperm bluntly pentagonal to almost round in section.
Morphology General Habit
Coarse glabrous aquatic or marshland perennials
Morphology Leaves
Leaves simply pinnate with toothed, mucronate leaflets
Morphology Reproductive morphology Inflorescences
Umbels numerous, compound, pedunculate, leaf-opposed; involucre and involucel conspicuous, of several linear to toothed or dissected bracts and bracteoles
Morphology Reproductive morphology Flowers
Flowers hermaphrodite or polygamous
Morphology Reproductive morphology Flowers Calyx
Calyx-teeth conspicuous to ± obsolete
Morphology Reproductive morphology Flowers Corolla
Petals white to yellowish, emarginate above with an incurved apical lobule
[FTEA]

Sources

  • Flora Zambesiaca

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

  • Flora of Iraq

    • 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 Backbone Distributions

    • 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

  • 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