1. Cymodoceaceae Vines

    1. This family is accepted.

[NTK]

Haigh, A. (2009). Neotropical Cymodoceaceae.

Morphology
Description

Habit : Herbs, marine aquatics, submerged, perennial ; rhizomes present, creeping. Leaves alternate ( distichous ), simple , with open basal sheath and small ligule , numerous axillary intravaginal squamules present; stomata and trichomes absent. Inflorescences borne at end of short erect shoots, usually of solitary flowers, rarely in cymes. Flowers unisexual (plants dioecious ); perianth absent. Staminate flowers: sessile or stalked; androecium with 2 stamens, the stamens fused back to back with apical prolongation. Pistillate flowers: gynoecium apocarpous, the ovaries superior , the carpels 2, the styles long, slender, often branched, the stigmas inconspicuous in Halodule Endl. or of two stigmatic stout stylodia in Syringodium Kütz.; placentation apical, the ovules 1 per carpel . Fruits indehiscent , small; endocarp stony.

General Description
Notes on delimitation
  • The Cymodoceaceae are placed in the Alismatales in the APGIII classification system.
  • They were previously placed in the Najadales by Dahlgren et al (1985) and also by Cronquist (1981).
Number of genera

See above

Status
  • Native.
General notes
  • Commonly known as sea-grasses or manatee grasses.
  • Cymodoceaceae occur in shallow, coastal, tropical or subtropical waters.
  • They can form extensive submarine meadows in shallow, clear waters with minimal wave action.
  • Some are important in the stabilization of shallow marine sediments, nutrient recycling, and as food sources for grazing marine animals.
Distribution
Distribution in the Neotropics

A sub cosmopolitan family of 5 genera and c.16 species.  Two genera comprising 5 species occur in the Neotropics.

  • Halodule (4 species in Neotropics).
  • Syringodium (1 species in Neotropics).
Diagnostic
Distinguishing characters (always present)
  • Herbs.
  • Submerged marine aquatics growing in shallow waters.
  • Leaves alternate (distichous), simple.
  • Plants dioecious; perianth absent; stamens 2, partially fused back to back.
Useful tips for generic identification

Key to genera of Neotropical Cymodoceaceae

1. Leaf blade distinctly terete; many flowers in conspicuous cymose inflorescences — Syringodium
1. Leaf bladelinear, flat; inflorescence 1-flowered or 2 flowers resembling a single flower — Halodule

Literature
Important literature

Cronquist, A. 1981. An Integrated System of Classification of Flowering Plants. Columbia University Press, New York.

Dahlgren, R. M. T., Clifford, H. T., & Yeo, P. F. 1985. The Families of the Monocotyledons. Springer, Berlin.

Hartog, C. Den, 1970. The sea-grasses of the world. Verhandl. Kon. Ned. Akad. Wetensch. Nat. 59(1): 1-275.

Kuo, J. & McComb, A.J. 1998. Cymodoceaceae. In: K. Kubitzki (ed.), The families and genera of vascular plants 4: 133-140. Springer Verlag, London.

Stevenson, D.W., 2004. Cymodoceaceae. Pp. 433-434. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. & Heald, S.V. (eds.). Flowering Plants of the Neotropics. New York Botanical Garden, Princeton University Press, Princeton.

[FTEA]

Cymodoceaceae, Henk Beentje. Flora of Tropical East Africa. 2002

Habit
Marine plants, perennial, dioecious, glabrous; rhizome creeping; vessel elements absent
Leaves
Leaves distichous or spiral; leaf-sheath amplexicaul, with 2 apical auricles, ligulate; blade linear with several parallel nerves, in between which tannin dots and dashes are visible
Flowers
Flowers terminal and solitary on a short branch, or in cymose inflorescences, sessile or stalked, small, water-pollinated; tepals absent Pistillate flowers of 2 free ovaries; ovule 1, pendulous Staminate flowers consisting of 2 anthers, these 4-locular, partially connate, dehiscing by extrorse slits; pollen thread-like, without exine
Male
Staminate flowers consisting of 2 anthers, these 4-locular, partially connate, dehiscing by extrorse slits; pollen thread-like, without exine
Female
Pistillate flowers of 2 free ovaries; ovule 1, pendulous
Fruits
Fruit an indehiscent nutlet; seed 1; endosperm absent

Images

Cymodoceaceae Vines appears in other Kew resources:

First published in Stud. Text-book Bot. 2: 553. 1895 [Mar 1895] (1895)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

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 Selected Plant Families 2019. 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

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
http://creativecommons.org/licenses/by/3.0