Taxonomy
Kingdom: Plantae or Protista
Division: Rhodophyta
Class: Florideophycidae
Order: Halymeniales
Family: Halymeniaceae
Genus: Prionitis
Species: lanceolata
Classification controversy:
Further proving that Prionitis lanceolata is a shifty fellow, in the past it has been classified under several other genera. Harvey, one of the first scientists who characterized it, originally thought it was Gelidium. It has also been mistaken for Sphaerococcus (all members in this genus have since been reassigned) and Grateloupia. In fact, a paper published in 2001 suggests that Prionitis species should be included in the genus Grateloupia, based on morphological and molecular similarities between the two genera. The authors especially make note of similarities between vegetative and reproductive structures as well as genetic similarities of a specific gene sequence (ribulose-1,5-bisphosphate carboxylase/oxygenase).Kingdom: Plantae
or Protista
It has been a classical
debate whether algae belong to the plants or the protists. Algae are not as complex
as members of the plant kingdom, since they lack vascular tissue, true roots,
and other such structures. However, most algae are considerably more complex
than protists, which are almost wholly unicellular and are not photosynthetic.
Despite this, Protista is currently the more acceptable kingdom designation for
the algae.
Division: Rhodophyta
Informally
called "red algae," members of this division derive their color from
phycoerythrin which is their dominant photosynthetic pigment. They store their
food as floridean starch. Most are perennial* and
dioecious*. Nonmotile spores and gametes
are a unique characteristic of the reds.
Class: Florideophycidae
Florideans
have a three-stage life history, consisting
of gametophyte*, carposporophyte*,
and tetrasporophyte* stage.
Sexual reproduction is oogamous*.
Order: Halymeniales
Cells
usually have one nucleus with one or a few chloroplasts without pyrenoids*.
Reproductive structures are often in sori*,
nemathecia*, or conceptacles*.
Family: Halymeniaceae
The
morphology of female reproductive structures and post-fertilization events
are the distinguishing characteristics between families, even though
vegetative structures are more practical for identification. However,
general morphological characteristics include the thallus* being
multiaxial*, erect, and mostly
bladelike. Tetrasporangia* are
cruciately* divided and are usually
isolated just beneath the surface of the thallus or loosely aggregated
in sori*. Spermatangia* are
usually in superficial patches.
Created by Alice Chiu, 2003. Images may be used with permission.