Methods
Habitats
Bibliography
Glossary
Schedule
Students
PHYCOLOGICAL SOCIETY OF AMERICA
Delesseria
decipiens Taxonomy
Division: Rhodophyta
Class: Florideophyceae
Order: Ceramiales
Family: Delesseriaceae
Genus: Delesseria
Species: decipiens
Herbarium specimen of Delesseria decipiens
Division Rhodophyta -
The Division Rhodophyta includes over 4,100 species of algae commonly know as the red algae. The major defining characteristics of the division include: possession of chlorophyll a and possibly chlorophyll d and the presence of phycobiliproteins, phycocyanin and phycoerythrin, a red pigment which is primarily responsible for the algae's unique color. Reproductive characteristics include the absence of flagellated sperm (spermatia) and the possession of carpogonia on the female gametophytes. Other defining characteristics include the arrangement of the thylakoids in the chloroplasts, which are not stacked but scattered individually in the chloroplasts, and the use of floridean starch a s a storage product.
Delesseria displays all of these characteristics, as well as other characteristics common among red alga, such as pit plugs and a brilliant red color.
Class Florideophyceae-
The Class Florideophyceae
is a diverse group of red alga containing species as
seemingly different as the coralline
algae and Botryocladia,
the sea grapes. These algae are all united, however,
by morphological similarities such as filamentous or pseudoparenchymatous construction, apical
cell division, the formation of pit connections,
and dioecious gametophytes.
In addition, members of the class Florideophyceae also
have carpogonia located
on a trichogyne,
as well as carpospores that
form on gonimoblast filaments.
Order Ceramiales-
The order Ceramiales is the largest
order in the red algae, and is grouped primarily by the morphology
of the algae's reproductive structures. A major characteristic of
the order is that the auxiliary
cell in the female gametophyte is
derived from a supporting cell only after fertilization. The carposporophyte is
in turn derived from this auxiliary cell and is surrounded by a distinct pericarp.
Algae of the order Ceramiales generally have isomorphic life
histories.
Genus Delesseria-
First described by J.V. Lamouroux in 1813 and named for French naturalist Baron Delessert, the genus Delesseria includes species from a variety of places around the
world including Delesseria sanguinea from
the west coast of Europe and Delesseria lancifolia from the Falkland
Islands and Antarctica. Of these, most scientific research
has been done on D. sanguinea, including
studies of seasonal
growth patterns and sensitivity to UV
light. Recent genetic analysis has questioned
the classification of the genus, suggesting that D.
decipiens and D. sanguinea are more
closely related to the genus Membranoptera then
to many of the other species currently in the Delesseria genus.
The blades of Delesseria species are generally
thin, flat and monostomatic while
the conspicuous midrib is often polystromatic.
Intercalary divisions occur in Delesseria except
in the primary axial cell row. Delesseria sanguinea
Image © M.D. Guiry www.algaebase.org
The location of reproductive structures is also an important characteristic of the genus. Cystocarps are located on fertile leaflets branching from the midrib in the female gametophyte, and have a single carpogonial branch on a supporting cell. Spermatangia on the male gametophyte are located all over the thallus of the alga. Finally, tetraspores are located on blades of the last two orders of branching along the midrib.
Species decipiens
Delesseria decipiens is an intertidal to
subtidal species of Delesseria that grows annually on the west coast
of North America (distribution).
It was first collected in 1859 from the Strait of Juan de Fuca near present day
Washington State, and was described by J. Agardh in 1872.
Ecology | Morphology | Glossary | Acknowledgments