The new international encyclopaedia . age(Xereocystis), which consists of a flexible leaf-less stalk swollen at the end into a hollowspherical float several inches in diameter. Thetop of the float bears long strap-like leaves thatextend on either side in the water, and arewhipped about by the wind and surf. Anotherinteresting form is the sea-palm (Postelsia),which grows on surf-beaten rocks and reefs, andhas a heavy, thick, erect stalk 12 to 18 incheshigh, with a thick crown of leaves that grow-out and bend downward in the form of the con-ventional palm tree. The stalk is so tough thatit may b
The new international encyclopaedia . age(Xereocystis), which consists of a flexible leaf-less stalk swollen at the end into a hollowspherical float several inches in diameter. Thetop of the float bears long strap-like leaves thatextend on either side in the water, and arewhipped about by the wind and surf. Anotherinteresting form is the sea-palm (Postelsia),which grows on surf-beaten rocks and reefs, andhas a heavy, thick, erect stalk 12 to 18 incheshigh, with a thick crown of leaves that grow-out and bend downward in the form of the con-ventional palm tree. The stalk is so tough thatit may be bent over at right angles by the forceof the waves without breaking. Lessonia, foundon the coast of Chile, has stalks so heavy andthick that they have been mistaken for treetrunks when washed up on the beach. The kel|i-iare one of the principal sources of iodine, whicli PH^OPHYCE^. 679 PHAGEDENA. is obtained from their ashes. They are also usedin enriching farm lands along the coast. In a very different division of the Phaeophyeese. Fig. 2. HOCKWEED (Fucas). a, branches bearing antheridia: b, oogonium with par-aphjses; c, eggs escaping from oogonium ; d, egg sur-rounded bj sperms ; e, germination of a fertilized egg. are the roekweeds and gulfweeds. The former,also called wrack and bladder-wrack. cover therocks between tide marks with thick fringinggrowth. Jlost of the rockweed is Fucus. a fonii witha forkingly branched thallus, that bears swollentips, and in some species special air bladders thatsene to Hoat the branches. The gulfweeds (Sar-gassum) have one of the most highly differentiat-ed vegetative bodies among the algae. The speciesare found in warmer waters than most brownaigs. In addition to the holdfast and branch-ing stalk, there are delicate leaves and smallberry-like air bladders on short pedicels, besidesspecialized portions that bear sexual species (as Sargassum bacciferum) willvegetate luxuriantly when floating in niidocean,thus forming the large
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