Cymodoceaceae Vines

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

Morphology General Habit

Habit : Herbs, marine aquatics, submerged, perennial; rhizomes present, creeping

Morphology Leaves

Leaves alternate (distichous), simple, with open basal sheath and small ligule, numerous axillary intravaginal squamules present; stomata and trichomes absent

Morphology Reproductive morphology Inflorescences

Inflorescences borne at end of short erect shoots, usually of solitary flowers, rarely in cymes

Morphology Reproductive morphology Flowers

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 Staminate flowers: sessile or stalked; androecium with 2 stamens, the stamens fused back to back with apical prolongation Flowers unisexual (plants dioecious); perianth absent

Morphology Reproductive morphology Fruits

Fruits indehiscent, small; endocarp stony.

Diagnostic

Key to genera of Neotropical Cymodoceaceae 1. Leaf blade distinctly terete; many flowers in conspicuous cymose inflorescences — Syringodium1. Leaf bladelinear, flat; inflorescence 1-flowered or 2 flowers resembling a single flower — Halodule 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.

Distribution

Native. 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).

Note

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. Number of genera: See above 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).

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

Morphology General Habit

Marine plants, perennial, dioecious, glabrous; rhizome creeping; vessel elements absent

Morphology 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

Morphology Reproductive morphology 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

sex Male

Staminate flowers consisting of 2 anthers, these 4-locular, partially connate, dehiscing by extrorse slits; pollen thread-like, without exine

sex Female

Pistillate flowers of 2 free ovaries; ovule 1, pendulous

Morphology Reproductive morphology Fruits

Fruit an indehiscent nutlet; seed 1; endosperm absent

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Submerged marine perennial herbs with slender creeping stems (rootstocks)

Morphology Leaves

Leaves linear with sheathing bases, tufted at nodes on the rootstock

Morphology Reproductive morphology Flowers

Flowers unisexual or (rarely) perfect, solitary or clustered, usually naked, rarely with minute bracts; perianth lacking. Staminate flower consisting of 1 sessile or 2 long-stalked, 2-celled anthers bearing thread-like pollen

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistillate flower of 1 or 2 fused carpels, sessile or stalked, with hair-like style

Morphology Reproductive morphology Fruits

Fruit a 1-seeded drupelet.

Distribution

Four genera with about 22 species, widely distributed in tropical, subtropical and temperate regions.

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

Morphology General Habit

Dioecious, marine perennials with creeping, monopodially or sympodially branched rhizomes; rhizome leafy or with scale leaves, herbaceous and rooting at the nodes or woody and rooting from the internodes

Morphology Leaves

Leaves distichous, with distinct blade and sheathing base; sheath ligulate, auriculate; blade 3- to several-nerved, narrowly or broadly ribbon-like or, rarely, terete and subulate

Morphology Reproductive morphology Inflorescences

Flowers usually solitary and terminal on short erect shoots or on branches of erect shoots, but forming cymose inflorescences in Syringodium

Morphology Reproductive morphology Flowers Perianth

Perianth absent

Morphology Reproductive morphology Flowers Pollen

Pollen grains filamentous and tightly coiled within the anther

Morphology Reproductive morphology Flowers

Female flowers sessile or shortly stalked, consisting of two free carpels, each carpel having either a simple, long style (Halodule) or a style divided into 2 or 3 slender stigmas, and containing one pendulous ovule Male flowers subsessile or stalked, consisting of 2 extrorsely dehiscent, 2-thecous anthers ± dorsally united and attached either at the same height or one slightly above the other (Halodule)

Morphology Reproductive morphology Fruits

Fruit a 1-seeded nut, indehiscent, either with a stony endocarp or viviparous

Morphology Reproductive morphology Seeds

Seed without endosperm.

Distribution

Family of five genera and about 20 species; for the most part occurring in tropical and subtropical oceans.