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About Seaweeds

some that are not (fossils). For example, Saccharina latissima (sugar kelp), a brown seaweed, is classified as follows:

Kingdom: Chromista. A kingdom is a large grouping of vaguely similar species thought to share a distant common ancestor. Other kingdoms include Animalia and Plantae.

Division: Phaeophyta (brown algae). A division is a slightly smaller group of species thought to share a common ancestor. The animal equivalent to division is phylum. The -phyta suffix designates divisional status. Other divisions include Chlorophyta (green algae) and Rhodophyta (red algae).

Class: Phaeophyceae. Classes designate groups within a division that have significant differences but are closely related. For example, birds and mammals form separate classes within the phylum Chordata (animals with backbones). The -phyceae suffix designates class. Other classes include Chlorophyceae (most green algae) and Bacillariophyceae (the diatoms).

Order: Laminariales. A class is subdivided into orders on the basis of features such as body plan and life cycle. In the brown seaweeds, the order Laminariales (large brown algae, the kelp) have intercalary growth, the Ectocarpales (small filamentous brown algae) have diffuse growth and the Fucales (common brown rockweeds) have apical growth. The -ales suffix designates ordinal status.

Family: Laminariaceae. Orders are subdivided into families on the basis of various features. Earlier, most members of the laminarialean family Alariaceae (the winged kelp) had sporophylls (special blades for spore production) and no branching. Most members of the laminarialean family Lessoniaceae were regularly branched and did not have sporophylls. The Laminariaceae lacked sporophylls and branching. Today, we know those features don’t reflect true relationships and the families of kelp are now defined by molecular DNA differences. The -aceae suffix designates familial status.

Genus: Saccharina. We can define a genus (plural: genera) as a group of closely related species that are usually not interfertile and are distinguished on the basis of some relatively small morphological feature, such as branching pattern. There may be several genera in a family. The generic name is always italicized or underlined.

Species: Saccharina latissima (Linnaeus) C.E. Lane, C. Mayes, L. Druehl and G.W. Saunders. Individuals making up a species are thought to be sexually compatible. Different species within a genus are considered to be sexually