Macrocystis integrifolia was considered a distinct species of giant

kelp Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "under ...

in the genus ''

Macrocystis ''Macrocystis'' is a monospecific genus of kelp (large brown algae). This genus contains the largest of all the phaeophyceae or brown algae. ''Macrocystis'' has pneumatocysts at the base of its blades. Sporophytes are perennial and the indiv ...

,'' based on blade and holdfast morphology. As of 2009, phycologists have collapsed ''Macrocystis integrifolia'' and the various other giant kelps into the single species, ''Macrocystis pyrifera.''

Description

Deep brown color on flattened rhizomes which are profusely dichotomously branched. Each is attached by branched root-like structures coming out of the sides of the rhizomes. Slender main stipes (about wide to long) come from the rhizome which is up to at the widest. Periodically wide and long flattened leaf-like branches derive from the stipe. They have furrowed surfaces and taper gradually, but then have an oval or rounded float where attached to the stipe. The blade-like branches have notched denticulate edges leading to the terminal blade at the tip of the stipe, which is separated by several smaller branches. Phylum: Phaeophyta, Class: Phaeophyceae, Order: Laminariales, Family: Lessoniaceae, Macrocystis integrifolia (Bory)
Pearson College UWC. Retrieved 6 February 2013

Life history

It is found on intertidal rocks or shallow subtidal rocks along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

coast of North America from

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost Provinces and territories of Canada, province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

.Abbott, I. A. & G. J. Hollenberg. (1976) ''Marine Algae of California.'' California: Stanford University Press. Macrocystis integrifolia Bory
DeCew's Guide to the Seaweeds of British Columbia, Washington, Oregon, and Northern California, Center for Phycological Documentation, University Herbarium, University of California, Berkeley, 2002. 13 July 2007 It prefers water about to deep and exposed to the open sea and normal salinities, yet sheltered from full wave action.
Pearson College UWC. Retrieved 6 February 2013 ''Macrocystis integrifolia'' alternates heteromorphic phases from a macroscopic sporophyte to dioecious microscopic gametophytes. It has been studied as a plant fertilizer, increasing bean yields up to 24% and chemical studies indicate presence of phytohormone-like substances.Temple, W. D., A. A. Bomke
Effects of kelp (Macrocystis integrifolia and Ecklonia maxima) foliar applications on bean crop growth
Plant and Soil, June 1989, Volume 117, Issue 1, pp. 85-92 (paywall) In 2009, a study concluded that ''

Macrocystis pyrifera ''Macrocystis pyrifera'', commonly known as giant kelp or bladder kelp, is a species of kelp (large brown algae), and one of four species in the genus '' Macrocystis''. Despite its appearance, it is not a plant; it is a heterokont. Giant kelp ...

'' is monospecific. Demes, K.W, Graham, M.H. & Suskiewicz, T.S. (2009). Phenotypic plasticity reconciles incongruous molecular and morphological taxonomies: the giant kelp, ''Macrocystis'' (Laminariales, Phaeophyceae), is a monospecific genus (note). Journal of Phycology 45(6): 1266-1269.

References

External links

Macrocystis integrifolia Bory
California Biota Home Page... Protoctista... Phaeophyta {{DEFAULTSORT:Macrocystis Pyrifera Laminariaceae Flora of the Pacific Marine biota of North America Flora of California Flora of the West Coast of the United States Species described in 1826 Flora without expected TNC conservation status