What is laminaria?



In such large forms, small portions showing the structure and development of the thallus and also the reproduction should be cut out with a razor and then placed in the fixing agent. The sporangia of Laminaria stain very deeply and quickly. Ironhaematoxylin is good, but be careful not to overstain. After this stain is just right, about 3 to 5 minutes in alcoholic safranin will stain the mucilaginous structures and add to the value of the preparation.

The zoospores from the sporangia germinate immediately, forming dioecious, filamentous gametophytes bearing antheridia and oogonia. The fertilized egg at once begins to develop into the Laminaria plant. So little is known about this stage that it would be worth while for those who are at the seashore to germinate the zoospores of any members of the Laminariaceae.

For habit study, small specimens up to 45 cm. in length can be mounted upon paper. They stick well and seldom need to be secured by gummed paper. Larger specimens may be allowed to dry and may then be stored away in a box. When wanted for use, wet them under the tap, or, better, in salt water; after using, let them dry and return them to the box. Specimens will stand 4 to 5 such soakings in fresh water; if a pint of salt is added to 3 or 4 gallons of water, the material may be soaked a dozen times before it passes its usefulness. If material has been fixed, in formalin, it may be washed in seawater not very thoroughly, but enough to remove the pungent odor-and then soaked in equal parts of glycerin and water. Use only enough of the glycerin to make the specimens flexible, not enough to make them wet to handle. In this way, material of Laminaria, Macrocystis, Nereocystis, Postelsia, and other large forms can be kept in condition for demonstration and will last for years without any attention. When not in use, they should be kept stored in a box.





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