The sporangia within each sorus
produce spores that germinate and develop into a prothallus, which grows into a heart-shaped gametophyte.
Sorus as whip-shaped, elongated main axis; infected plants sterile; whip often more than 1 m long, the diameter decreasing from ca.
Sori in some to numerous flowers of an inflorescence; a single sorus with one central columella and a peridium, both made of fungal cells; columellae ca 4-7 mm long; peridia dirty white to brownish, rupturing with 3-4 lobes.
Sorus area (A) of an individual Macrocystis was estimated as
This product (slw) was doubled because a single sorus of approximately equal area occurs on both sides of a sporophyll (Neushul 1959).
A large decrease in sorus area and in the number of fronds per individual was observed immediately following a large storm in the 30 permanently marked Macrocystis.
In contrast to Macrocystis, Pterygophora reproduces seasonally (late fall and winter) and the amount of sorus area on an individual does not change appreciably during the reproductive season (Reed et al.
where o is the observed number of individuals showing the same directional change in reproductive condition (i.e., a change in sorus area or sporangium density for Macrocystis and Pterygophora, respectively), and e is the expected number of individuals showing the same directional change in reproductive condition under conditions of asynchrony.
Total sorus area was estimated in two ways: sorus area per plant and sorus area scaled to plant size.
A representative sporophyll from each fertile plant sampled in the field was brought back to the laboratory where a 6.6-[cm.sup.2] core was taken from the darkest portion of the sorus. Cores pooled by species within sites were cleaned, rinsed, and subjected to a mild temperature/osmotic shock to induce spore release (Reed et al.
Simple linear regression was used to determine if temperature explained variation in sorus area.
Similarity in sorus area, chemical composition, and viability among sites was assessed quantitatively as Pearson product-moment correlation coefficients calculated for all between-site comparisons.