94 
THE SEAWEEDS 
The reproductive cells are zoospores produced in elongate sac-like 
unilocular sporangia grouped in more or less localized sori accompanied 
by parapliyses. The sporangia appear on the surface of the thallus and 
not in conceptacles as in the Cyclosporinae. 
The Order is represented by’ multitudes of genera and species in the 
colder Northern Hemisphere. In Australian waters only three genera 
occur — EcMonia, Macrocystis, and Lessonia (Tasmania only). 
The plants are useful from the supply of iodine which they afford. 
EC KLONI A 1 I ornemann. 
Attached by a much-branched holdfast. Stipes simple, elongate ; lamina 
pinnatifid, ribless, broad. Unilocular sporangia, elongate-ellipsoid, accom- 
panied by inarticulate simple club-shaped parapliyses, forming sori in the 
lower parts of the pinnae. 
Fig. 52 . — Ecklonia rcudiata. 
