Cell wall: generally contains cellulose (1-10% of thallus dry-weight), alginic acid, and sulfated polysaccharides

Plastids: varies among genera – may be from one to many per cell; typically have a girdle lamella; have a periplastidal endoplasmic reticulum, which is continuous with the nuclear envelope

Pigments: fucoxanthin, which gives the algae their characteristic greenish-brown color; chlorophyll a; chlorophylls c₁ and c₂; beta-carotene; and violaxanthin

Photosynthetic reserve product: laminarian

(Lee, 1999; Graham & Wilcox, 2000)