David B. Fankhauser
Professor of Biology and Chemistry
University of Cincinnati Clermont College
Batavia OH 45255
rvsd 29 March 1993, 6 April 1994, 25 Mar '95, 19 Mar '96, 26 Mar '97, 28 Mar '98, 5 April 01
Fresh flowers of two families of plants
[ Dissecting Scope and dissecting kits should have been introduced first]
Illumination for microscope
Summary of evolutionary trends among angiosperms (flowering plants):
|1||number of flower parts||many, indefinite parts||few parts, fixed numbers|
|2||relation of parts||separate||fused|
|3||symmetry of parts||radial||bilateral|
|4||location of ovary||superior||inferior|
I. Take a short field hike to pick two wildflowers on a sunny day:
1) a fresh Dandelion
(representative of the family Compositae) and
2) some other wildflower, not a composite.
For instance, Purple Dead Nettle (family Labiatae), Yellow Rocket (family Cruciferae), Common Violet (family Violaceae), etc.
II. Answer these questions in your notebook for each of the two flowers before dissection:
a) What is its scientific name?
b) To what family does it belong, give characteristics of this family.
c) Briefly summarize the ecological niche where you found it.
III. Dissect out a complete
from the dandelion .
Illustrate as large as you can in a single field under the dissection scope to show and label:
|Flower part||traits of flower parts in Dandelion||Etymology|
|carpal (also called pistil)||extends from inferior ovary to stigma||"fruit/little"|
|ovary||inferior in the Dandelion||"egg/thing connected with"|
|style||enclosed by stamen filaments in the Dandelion||"pillar"|
|stigma||bifurcated in the Dandelion||"mark" or "spot"|
|petals||fused in the Dandelion||"leaf"|
|corolla||tubullar in the Dandelion||"crown/ little"|
|filament||fused in the Dandelion||"spin/agent"|
|anthers with pollen||in the Dandelion, fused to distal style||"flower"|
|sepals||these are fine and filamentous in Dandelion||"covering"|
|calyx||turns into "down" of the mature flower||"cup" or "receptacle"|
Indicate in your notebook which features of the flower structure indicate relative evolutionary advancement over early primitive flower structures.
IV. Dissect and illustrate your second flower.
Provide for it the same information as for the dandelion.
V. Carefully clean and return the dissecting scope and light to their proper storage places.