BROWN · HETEROKONTOPHYTA (PART II) Notebook Requirements (12 drawings) 1. pyrifera – 4 drawings (thallus, scimitar blade (apical end), cross section of sporophyll, and sporophyll blade) 2. leutkeana –2 drawings (thallus and lateral section) 3. setchellii – 1 drawings (thallus) 4. marginata – 1 drawing (thallus and cross section of sporophyll) 5. Egregia menziesii – 1 drawing (at least 2 different blade types and/or terminal blade) 6. Lessoniopsis littoralis – 1 drawing (thallus) 7. Unknowns – 2 Thallus drawings and steps in key

C. Order Laminariales Family :

• 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.

• Draw a sporophyll blade and a vegetative blade.

Q: Where is each type of blade located on the thallus? How can you visually tell them apart from each other?

Species: Nereocystis leutkeana To transport sugars throughout the plant body of this large , Nereocystis (and M. pyrifera) has sieve tubes in the outer medulla.

• Draw the thallus of N. leutkeana, label stipe, pneuomatocyst, holdfast sporophylls, and sori (if present).

• Prepare and draw a lateral section of the stipe. Identify and label mucilage ducts (if visible - in cortex), sieve plates (in medulla)/sieve elements (trumpet hyphae), cortex and medulla. Work on this together to get a good cross section.

Q: What is the purpose of sieve plates?

Q: Compare and contrast Macrocystis and Nereocystis: What morphological differences are there? Which species is annual? Which is perennial? What environment are each species found? (hint, check MAC)

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? Understand the lifecycle of this order.

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. Examine and draw the overall thallus. Label holdfast, stipe, blade and sori (if present).

Family Species:

• Sketch thallus, label holdfast, stipe, terminal blade, midrib, sporophylls and sori (if present)

• Draw a cross section through a sorus patch of Alaria, label sporangia, cortex, and medulla.

Family Species: Egregia menziesii Simplified blade types found in Egregia menziesii.

• Draw thallus. Label the rachis (specialized Filiform Blade blade/central axis = “midrib”) and identify and label the blades coming off the rachis (see Stipitate Blade diagram for different types of blades). Also label pneumatocysts. Spatulate Blade Q: Where is the meristematic region of thallus? Pneumatocyst

Species: Lessoniopsis littoralis 1. Sketch the thallus of L. littoralis, label stipe, blades, holdfast, sporophylls and sori. (Hint: see your MAC for a description of the sporophylls).

H. Unknowns As in previous labs, key to species (and draw) the two unknowns presented to you. Be sure to write out each step of your path through the dichotomous.

Life Cycle of the Laminariales Diplohaplontic e.g. Laminaria setchellii antheridia produce sperm

1N zoospores

1N syngamy

meiosis occurs in oogonium unilocular sporangia

sori on 2N adult 2N embryonic