Transcript Bio328_lab5_major_families_II

Biology 328
Plants and People
Lab – 5: Major Families II
http://www.desktopscenes.com/Scenes%20from%20Muir%20Woods%20(2003)/slides/Path%20to%20the%20Woods.html
Objective
• To familiarize you with vegetative and floral
morphology of 2 families
 Grasses - Poaceae/Graminae
 Legumes- Fabaceae, Caesalpiniaceae, and
Mimosaceae
Grasses - Poaceae
Vegetative morphology
• Roots – Fibrous
Monocot
• Stem (Culm) – Nodes and internodes
▫ Stem modifications – rhizome,
stolon/runner
• Leaves – Sheath, lamina, ligule (outgrowth
between sheath and lamina)
Floral morphology
• Flower/Floret – Basic unit, parts of 3’s , highly reduced,
non showy
▫ Perianth (calyx + corolla) – As lodicules at the base of
the ovary.
▫ Stamens
▫ Pistil - Ovary, styles, and plumose stigmas
▫ 2 fertile bracts - Lemma (larger) and Palea (smaller)
• 2 or 3 florets – Spikelet
• 2 sterile bracts - Glumes
• Fruit – Grain/Caryopsis
Legumes- Fabaceae,
Caesalpiniaceae, and Mimosaceae
Floral morphology
Subfamily
Fabaceae
Caesalpiniaceae
Mimosaceae
Floral characteristics
Zygomorphic
Papilionaceous, Standard/Banner (upper petal), wings (adjacent
petals), Keel FUSED (Boat shaped part), Diadelphous stamen
(9 + 1)
Fruit - legume
Zygomorphic
Papilionaceous, Standard/Banner (upper petal), wings (adjacent
petals), Keel NOT FUSED, stamens (10)
Fruit – legume
Actinomorphic
Globose head inflorescence
Fruit – legume
Today’s lab
Poaceae
• 1. Examine an oat (Avena) spikelet. Note the two basal glumes,
which completely enclose the florets. There should be three florets
above the glumes, with the terminal one not completely developed.
Separate a palea from the lemma that encloses it. Is there any
difference between a palea and a lemma? Also, observe the flower.
• 2. Diagram the oat (Avena) spikelet labeling glumes, florets, and the
lemma and palea of one floret.
• 3. Examine and diagram a Bromus spikelet labeling the organs of its
basic structure, i.e., glumes and paleas and lemmas of each floret.
• 4. Examine specimens of other grass genera on display.
Legumes- Fabaceae
Subfamilies – Papilionoideae, Caesalpinioideae, and
Mimosoideae
• Compare the sample material with descriptions and
terminology given in lecture and laboratory notes. For
each floral sample, examine floral structure, paying
close attention to the arrangement and structure of
the androecium and perianth.
• Examine the legumes on display. Which of them are
foods? Which of them are forage?
Summary
Today’s Lab
• Familiarizing vegetative and floral morphology of
grasses and legumes
Next week’s lab
• Quiz - Major Families II
• Wood, paper and Cushing library