Delesseria sanguinea (Hudson) J.V.Lamouroux

Nomenclature and Basic Classification

Delesseria sanguinea (Hudson) J.V.Lamouroux is a common, bright red perennial alga.

Growth Form and Holdfast

It grows flat, leaf-like red blades from a discoid holdfast.

Blade Cell Structure and Dimensions

Each blade is monostromatic, meaning it is made of a single layer of cells, and can grow up to 25 cm long and 8 cm wide.

Stipe Characteristics

Each blade grows from a cylindrical, stalk-like stipe that only branches near its base.

Blade Venation and Tip Shape

Blades have a visible central midrib with lateral veins, and their tips are rounded.

Smaller Similar Algae Species

Several similar algae exist: Apoglossum ruscifolium, Hypoglossum hypoglossoides, and Membranoptera alata are all much smaller than Delesseria sanguinea.

Similar Algae of Comparable Size

Phycodrys rubens reaches a comparable size, but is easily distinguished by the lobed edges of its blades.

Habitat and Depth Range

This alga grows on rock in pools at low water, and also grows in sublittoral zones down to 30 m deep as an epiphyte on other large algae.

Geographic Distribution

It is common around Ireland, Great Britain, the Isle of Man, and the Channel Islands, ranging north to Norway and Iceland, and south to Spain.

Reproductive Bladelet Location

All reproductive bladelets of this alga form on the midrib.

Male Reproductive Bladelet Size

Male reproductive bladelets reach 6 mm long.

Spermatangial Sori Characteristics

Spermatangial sori develop on both sides of the blade's midrib, forming a continuous, oval-shaped sorus on the blade.

Female Reproductive Structures

Female bladelets have a narrow lamina, and cystocarps form near the apex on a short stalk.

Tetrasporangial Bladelet Traits

Tetrasporangial bladelets are oval-shaped and grow up to 4 mm in size.