Angiosperm Reproduction

	ANGIOSPERM REPRODUCTION Copyright 2001 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
Taraxicum officinale	This page has been accessed times since 5 April 2001.	Dandelion floret

Purposes:

to demonstrate the parts of the flower through student activity
to determine the relative evolutionary advancement in student-selected flowers
to reveal at low magnification the beauty of even the most common "weed" flowers.

SUPPLIES:

Fresh flowers of two families of plants

EQUIPMENT:
[ Dissecting Scope and dissecting kits should have been introduced first]
Dissection kits
Dissecting microscope
Illumination for microscope

Summary of evolutionary trends among angiosperms (flowering plants):

	TRAIT	PRIMITIVE CONDITION Bloodroot	ADVANCED CONDITION Purple Deadnettle
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

ACTIVITIES:

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 floret 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.