Ceratophyllales is an order of dicotyledonous flowering plants that are cosmopolitan in distribution. The Ceratophyllales members are aquatic herbs having whorled, dichotomously branched, and serrulate leaves.
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The monoeciousWhat is monoecious?Pertaining to plants, individuals of which bear both staminate and pistillate flowers, but not necessarily perfect flowers. plants with solitary and unisexual flowers undergo underwater pollination. The species of Ceratophyllales are economically used as aquarium plants, such as the coontails and tropical hornworts.
APG IV system of classification places Ceratophyllales as a sister to the eudicots. Ceratophyllales contains only 1 family, 1 genus, and 6-7 species. The sole family, Ceratophyllaceae, has Ceratophyllales as the only genus.
Members of Ceratophyllales are distributed worldwide. Consequently, the range of the species extends across all or most of the world. Ponds, marshes, and quiet streams of the tropical and temperate regions are the habitats of these Ceratophyllum members.
- Plant Type: Species of the Ceratophyllales are perennial herbaceous. The plants are typically submersed or possess the quality of growing entirely underwater.
- Stem: The plants have slender and branched stems.
- Leaves: The leaves of the Ceratophyllales plants are cauline (attached to an above-ground stem). Usually, there are 4-12 whorled and sessile leaves. They are exstipulateWhat is exstipulate?Without stipules; Stipule is a small structure of appendage found at the base of some leaf petioles.. The leaf blades are dichotomously divided into 1-4 times. The margins are serrulate.
- Flowers and Inflorescence: The flowers are unisexual and monoecious. The flowers are in the inflorescence of solitary and axillary. Usually, the male and female flowers are situated on alternate nodes.
- Sepals and Petals: The flowers are uniseriate. The flowers have 8-12 linear tepals; basally fused.
- Stamens and Carpels: The stamens are typically numerous. The staminate flowers are with 10-20 stamens. The gynoecium is unicarpellous (1 carpel).
- Ovary and Fruit: The flowers consist of a superior ovary. The fruit is achene. It has a persistent and spiny style.
- Seeds: The seeds of the Ceratophyllales are exalbuminous. Typically, there is only 1 seed per fruit. The perispermWhat is perisperm?A food reserve tissue found in the seeds of plants such as coffee, beets, or spinach. It is formed outside the embroyo sac. is absent.
Ceratophyllales Flowers and Reproduction
Ceratophyllum flowers are small and inconspicuous. The male and female flowers are on the same plant and are usually on alternate nodes. Their flowers have uniseriate perianth.
Typically, there are 8-12 linear tepals that are basally fused. Sometimes, the tepals are interpreted as bracts or modified leaves.
Hornworts undergo underwater pollination. During the maturity of the male flowers, the anthers individually break off. These anthers settle in the water. The moment the anthers reach the groove near the female flower’s stigma, pollination occurs.
The reproduction of the hornworts is via a waterborne sperm. The sperms travel from the antheridium (male sex organ) to the archegonium (female sex organ). The fertilized egg in the archegonium becomes an elongate sporangium. During the growth of the elongate sporangium, it will release the spores.
Ceratophyllales Example Species
Species of Ceratophyllales are aquatic herbs. Economically, they are used as a protective cover in fisheries and aquarium plants.
- Hornwort/Coontail – Coontail is a popular aquarium plant. It is also used as a health supplement.
- Spiny Hornwort – The spiny hornwort is commonly used as an aquarium plant.
- Prickly Hornwort – A plant for spawning.
- Soft/ Tropical Hornwort – Soft/tropical hornworts are also used in the aquarium. It is a plant for spawning.
- Ceratophyllum australe
- Ceratophyllum platyacanthum
- Ceratophyllum tanaiticum