Using the Microscope

1. Eye-strain can be avoided by insuring that your microscope is properly adjusted for YOUR eyes. Set up your scope so that it receives bright light from the lamp. Focus, at highest magnification, on the end of your teasing needle. Shut your left eye and focus with the main focus adjustment; then shut your right eye and focus with the adjustment on the left objective. Do this every time you use the scope. Use the zoom ring or dial to increase or decrease the magnification.
2. You are responsible for your immediate working area! At the end of each lab period, be certain that: 1) your scope is covered and returned to the cabinet, 2) your bench space is clean and free of plant material, and 3) your table lamp is OFF.

2. Gladiolus (Liliopsida):

Obtain a flower, examine it, and determine the following: a. sepal number:_____, b. petal number:_____, c. stamen number:_____,
d. pistil number:_____, e. ovary position relative to androperianth:___________

This is a SYNCARPOUS GYNOECIUM, i.e. the pistil is COMPOUND (composed of more than one carpel). The carpels are fused to form a single structure. Concentrate on the gynoecium and answer the following questions: a. number of style branches:_____, b. number of locules:_____, c. number of carpels:_____, d. placentation type:__________________
Examine table 10-2 from Walters and Keil (p. 170) and  construct a floral formula for Gladiolus: __________________________________________________
SKETCH YOUR GLADIOLUS (long-section of flower and cross-section of ovary)
 
 

Circle only those descriptive terms that apply to Gladiolus:

If you are unsure of the meaning of any of these terms, refer to the page on the basics of reproductive anatomy

ACTINOMORPHIC	ZYGOMORPHIC	INCOMPLETE
COMPLETE	3-MEROUS	5-MEROUS
POLYSEPALOUS	SYNSEPALOUS	GAMOPETALOUS
SYMPETALOUS	APETALOUS	PERFECT
IMPERFECT	MONADELPHOUS STAMENS	DIADELPHOUSS STAMENS
EPIPETALOUS STAMENS	TETRADYNAMOUS STAMENS	HYPOGYNOUS
PERIGYNOUS	EPIGYNOUS	TRICARPELLATE
APOCARPOUS	SYNCARPOUS	SIMPLE PISTIL
AXILE PLACENTATION	PARIETAL PLACENTATION	MARGINAL PLACENTAION
SEPTUM	BILOCULAR OVARY	TRILOCULAR OVARY
SPIKE	RACEME	PANICLE
UMBEL	HEAD


The genus Gladiolus contains about 250 species native only to the Old World. The lab key key doesn't include this taxon, but your floral formula for Gladiolus contains enough information to identify the family to which it belongs, if you pretend the flowers are regular. First, however, assign it to the proper class. You have enough information to make this determination (see W&K, pp. 397-398.)

Record your progress through the key by listing the series of couplets that you follow, starting with the first: CLASS____________________________ COUPLETSEQUENCE_________________________________________________________________________ FAMILY:_____________________

3. Sesbania (Magnoliopsida):

Obtain a single flower (click for a similar flower) and do your best to construct a floral formula that will describe the basic structure of this flower. Examine mature ovaries of Sesbania plants on side table if you are unable to determine carpel number from the immature gynoecium. Have your TA check your floral formula., and compare against that presented by W&K (p. 277.)
FLORAL FORMULA _______________________________________________

KEY TO FAMILY:_______________________________________________________
FAMILY _______________________
Have your Lab Instructor check couplet sequence and family determination. Note distinctive characteristics of this family (see W&K, p 277, fig. 12-18 and wall chart), i.e., PAPILIONACEOUS FLOWER, DIADELPHOUS STAMENS, UNICARPELLATE GYNOECIUM.

SKETCH the corolla, androecium, and gynoecium of Sesbania

Circle only those descriptive terms that apply to Sesbania:

If you are unsure of the meaning of any of these terms, refer to the page on the basics of reproductive anatomy
ACTINOMORPHIC	ZYGOMORPHIC	INCOMPLETE
COMPLETE	3-MEROUS	5-MEROUS
POLYSEPALOUS	SYNSEPALOUS	GAMOPETALOUS
SYMPETALOUS	APETALOUS	PERFECT
IMPERFECT	MONADELPHOUS STAMENS	DIADELPHOUSS STAMENS
EPIPETALOUS STAMENS	TETRADYNAMOUS STAMENS	HYPOGYNOUS
PERIGYNOUS	EPIGYNOUS	TRICARPELLATE
APOCARPOUS	SYNCARPOUS	SIMPLE PISTIL
AXILE PLACENTATION	PARIETAL PLACENTATION	MARGINAL PLACENTAION
SEPTUM	BILOCULAR OVARY	TRILOCULAR OVARY
SPIKE	RACEME	PANICLE
UMBEL	HEAD

4. Helianthus (Magnoliopsida):

A member of the large, important and taxonomically complex family, ASTERACEAE (COMPOSITAE). You should become familiar with the unique structures and terms associated with this family. The inflorescence is a HEAD (CAPITULUM)-- numerous, small flowers (FLORETS) attached to a common receptacle. The entire head is subtended by an INVOLUCRE of bracts called PHYLLARIES. Examine the individual flowers and compare against diagrams in W&K (p. 302) and the wall chart.
DIAGRAM both disk and ray flowers. Label ovary, pappus, corolla, style, and androecium. Which flowers in this inflorescence are perfect?____________ imperfect________? Is the receptacle chaffy?_________.
Compare the Helianthus androecium against that of Sesbania. How do they differ in structure and terminology:
Sesbania = ___________________________
Helianthus =__________________________

Key Helianthus to family:
COUPLET SEQUENCE___________________________________________________________________________
FAMILY: ___________________________________________________. Return to the Table of Contents for the lab
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last updated 10 February 2005 by MDR