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Prophyll (prophyllum)
- First leaf of a lateral shoot.
- Two-nerved.
- Born between the main axis and the lateral
axis.
5. Branching of the shoot
Intravaginal = lateral shoot emerges from the
apex of the enclosing sheath; most common.
Extravaginal = lateral shoot breaks through the
base of the enclosing sheath, such as in a
rhizome or in basal branching; less common.
Tillering = branching at the base to produce a
clump of more-or-less erect culms.
Be able to diagram a grass shoot system, showing node, internode, sheath, ligule, blade, bud, lateral shoot, and
prophyll.
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STUDY QUESTIONS
1. What are the four parts of a grass shoot system?
2. Define: primary root
adventitious root
fibrous root
axillary bud
annual, perennial
caespitose
tufted
adaxial
abaxial
convolute
involute
conduplicate
revolute
glabrous
pubescent
scabrous
ciliate
glaucous
pilose
hirsute
villous
scale
bract
spathe
tillering
3. Distinguish between a rhizome and a stolon.
4. Name the parts of the grass leaf.
5. How many leaves are borne at each node of the culm?
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6. What are 3 functions of the sheath?
7. Describe the prophyllum and its position.
8. Distinguish between closed and open sheaths.
9. What's the difference between a scale and a bract? Give examples.
10. Name 4 grass genera that always have closed sheaths and 4 that sometimes have closed sheaths.
11. Describe 5 features that aid in determining if a plant is annual or perennial.
11. How long-lived are the primary and adventitious root systems?
12. What are intravaginal and extravaginal branching?
13. How would you distinguish a rhizome from a root?
14. Where do grasses store their food?
15. Describe the three main forms of the ligule.
16. What New Mexico grass lacks a ligule?
17. Be able to diagram clearly a grass shoot system, showing nodes, internodes, sheaths, ligules, blades, buds, lateral
shoots, and prophylls.
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REPRODUCTIVE STRUCTURES
“The basis of human proliferation is not our own seed but the seed of grasses.”
Evan Eisenberg, “Back to Eden” (1989).
Additional Reading: Harrington, p. 16-34.
The Spikelet = a highly modified shoot system.
A. Glumes
B. Lemmas
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C. Palea
2. The Flower
A. Gynoecium = female reproductive structures
Ovary
Ovule
Styles
Stigmas
Pistil
B. Androecium = male reproductive structures
Filament
Anther
Stamen
Pollination
C. Perianth = sepals and petals collectively