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C. Origin
Native (indigenous)
Exotic
Adventive
Naturalized
Introduced
Weeds and weedy = who knows?
2. Relation to time
3. Ethics
D. Form
1. Tufted (cespitose)
2. Sodformer (rhizomatous & stoloniferous)
E. Response to grazing
1. Decreaser
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F. Forage value
G. Dispersal Mechanisms of the seed.
H. Variation: Keep in mind that the individuals of a plant species, just like humans, are not all alike. The same
species may be annual in one situation, perennial in another; it may have one race adapted to alpine talus slopes and
another race adapted to lower elevation oak woodlands; some years it may grow only 3 cm tall, the next be 100 cm
tall; the same individual plant may be green in the spring and purplish in the fall; it may be sexual one season and
apomictic the next; it may be excellent forage for cattle but toxic to sheep.
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STUDY QUESTIONS
1. Which of the subfamilies are cool season, which are warm season?
2. Be able to describe the photosynthetic cycles for cool and warm season grasses. What are the advantages and
disadvantages of each?
3. How is the presence of specialized chloroplasts related to the photosynthetic cycle of a warm season grass?
4. Describe the characteristics of a Kranz grass and a non-Kranz grass.
5. Define: native
exotic
adventive
naturalized
introduced
decreaser
increaser
invader
phytomere
6. Describe the characteristics of a long-shoot grass and a short-shoot grass.
Note for upcoming lectures: Be able to diagram the “Field Features” (spikelets and other important features) for the
grass genera that we discuss in class. I will diagram them on the board, and you can supplement your diagrams with
lab notes and drawings.
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CHLORIDOIDEAE SUBFAMILY
When I recline on the grass I do not catch any disease,
Though probably every spear of grass rises out of what was once a catching disease.
Walt Whitman, “This Compost” (1881).
This is a relatively recently recognized subfamily, which is not found in the older literature. Members of this
subfamily were placed in the “Festucoideae” in Hitchcock’s Manual. Has been called “Eragrostoideae” but this is a
later homonym.
ERAGROSTIDEAE TRIBE
The tribe is sometimes spelled Eragrosteae.
Eragrostis, lovegrass
Muhlenbergia, muhly
Gotthilf Heinrich Ernst Muhlenberg (1753-1815): Pennsylvania born, pastor of Lutheran church at Lancaster,
pioneer botanist, author of early work on grasses.
Thomas Conrad Porter (1822-1901): classicist, poet, professor of botany, Lafayette College, Pennsylvania;
author of first Synopsis of Flora of Colorado; also Calamagrostis porteri, Melica porteri, Stipa porteri.
John Torrey (1796-1873): prominent physician, chemist, and botanist, College of Physicians and Surgeons in
New York, contemporary of Asa Gray, named many western collections.