Ochrophyta Part II Notebook Requirements (14 drawings) 1. Desmarestia sp.- 2 drawings (thallus from press and trichothallic growth) 2. Laminaria setchelli- 3 drawings (thallus and sorus cross section) 3. Macrocystis pyrifera – 4drawings (entire thallus, apical end, transverse cross section, longitudinal section) 4. Nereocystis leutkeana – 1 drawings (entire thallus) 5. Pterygophora californica – 1 drawing (entire thallus) 6. Alaria marginata – 1 drawing (entire thallus from press) 7. Egregia menziesii – 2 drawing (entire thallus of adult plant, one brach of a young plant) 8. Unknown(s) - steps to key D. Order Desmarestiales Species: Desmarestia spp. • Draw the entire thallus of Desmarestia. (Use the herbarium pressing) • Look at a prepared slide and draw what you see. Q: What kind of growth does Desmarestia exhibit? E. Order Laminariales Family Laminariaceae Species: Laminaria setchellii The holdfast of this species is composed of stiff, branched haptera. Each holdfast produces a single, long stipe. Sori appear as irregular darkened patches on the blades, but not all blades have sori. 1. Prepare and draw a cross section of the sorus. Look for and label sporangia, cortex and medulla. 2. Examine and draw the overall thallus. Label holdfast, stipe, blade, sori and the location of the meristem. 3. Look at the prepared slide, draw and label what you see. Species: Macrocystis pyrifera To transport sugars throughout the plant body of this large kelp, M. pyrifera has sieve elements in the medulla. • Examine and sketch the thallus of M. pyrifera. Label stipe, blades, sporophylls, holdfast, pneumatocysts and location of intercalary meristem. • Examine and sketch the apical end of M. pyrifera noting the scimitar blade. • Prepare and draw a transverse cross section of the stipe. Ide ntify and label mucilage ducts (in cortex), sieve plates (in medulla), cortex and medulla. Work on this together to get a good cross section. Q: What is the function of a sieve plate? • Prepare and draw a longitudinal cross section of the stipe. Identify and label the sieve elements (trumpet hyphae), medulla, and cortex. • Compare the vegetative blade to the sporophyll blade shown on page 256 in the MAC (Macrocystis integrifolia which is now just the intertidal morph of M. pyrifera). Q: Where is each type of blade located on the thallus? How can you visually tell them apart from each other? Q: How does M. pyrifera deal with herbivory on its sporophylls which are located so close to the substrate? Species: Nereocystis leutkeana • Draw the thallus of N. leutkeana, label stipe, pneuomatocyst, holdfast sporophylls, sori (if present) and meristem Q: Compare and contrast Macrocystis and Nereocystis: What morphological differences are there? Which species is annual? Which is perennial? In what environment are each species found? (hint, check MAC) Q: How do Nereocystis spores get to the substrate to settle? Q: What is the life history of Laminariales? Q: For algae in Laminariales – Is the macro-thallus (the algae we have in the water table) 1N or 2N? How do you know? Family Alariaceae Species: Pterygophora californica Pterygophora californica also has a holdfast of stout, branched haptera. At the base, the stipe is unbranched and cylindrical, becoming flattened in the upper portion, and terminating in a single vegetative blade. The lateral blades are sporophylls. • Examine and draw the external morphology of the thallus. Label the holdfast, terminal blade, stipe, sporophylls, sori (if present) and location of the meristem. Species: Alaria marginata • Sketch thallus, label holdfast, stipe, terminal blade, midrib, sporophylls, sori (if present) and the location of the meristem. Q: Compare and contrast the location of sporophylls in Pterygophora and Alaria. Family Lessoniaceae Species: Egregia menziesii • Draw entire adult thallus. Label the rachis (specialized blade/central axis = “midrib”) and identify and label the blades coming off the rachis (see diagram for different types of blades). Also label pneumatocysts and sporophylls, and meristem. Q: Where is the meristematic region of thallus? • Draw the blade of a juevinile plant. Lable blade types, pneumatocysts, and sporophylls if present. Q: How is the juevinille blade different from the adult blade? Unknowns: Please key out two of the live algal specimens from lab today. Write out your keying steps. There will be two unknown browns on next weeks practical. .