20 COLLEGE BOTANY 



other parts, such as buds, bulbs, flowers and fruits, are modifica- 

 tions of these primary parts. We will give our first considera- 

 tion to the anatomy, histology and reproduction of these plants. 

 Second, to the physiology of plants. Third, to the taxonomy 

 and utilization of plants. 



LABORATORY EXERCISES. 



Purposes. Laboratory work is not only for the purpose of learning 

 facts concerning plants and plant growth, but also for the purpose of de- 

 veloping the powers of close observation and accuracy. The drawings and 

 notes are records of the work and good index of the ability of the student. 

 Neatness is essential to good work, but artistic finish although very 

 desirable is of minor importance. Study the subject carefully and thor- 

 oughly before attempting to make the drawings. 



Microscope. The microscope is a complicated piece of apparatus and 

 should be properly cared for. It consists of two optical parts which are 

 supported by a mechanical stand. The! two optical parts are set in either 

 end of a tube, the upper end known as the ocular and the lower as the 

 objective. The light is concentrated and reflected by a mirror so as to pass 

 through the object to b studied, thence through the two optical parts. 

 The objective forms an image of the object which is magnified by the ocu- 

 lar. The student should learn the general principles involved in the use 

 of the microscope before beginning the study of objects. 



Exercise 1. Examine prepared slides of pollen grains or other material 

 showing individual cells of various forms and sizes. 



Exercise 2. Examine the green slime found growing in damp places, on 

 the bark of trees, brick walls, etc. Note the cell walls, cell contents and 

 cell divisions. 



Exercise 8. Examine the cells of Spirogyra. Note the size and shape 

 of the cells and their relation to each other. Note the cell walls, the pro- 

 toplasm and the chromatophore (or chloroplasts ) . Why does a part of the 

 chloroplast appear bright and the other part dim ? Do you see the nucleus ? 



Examine some of the Spirogyra that has been kept in alcohol for 24 

 hours or longer. What is the effect ? Do you see the nucleus ? Add a drop 

 of eosin to the preparation. What is the effect? 



Examine some of the Spirogyra that has been kept in 5 per cent, salt 

 solution for a few minutes. What is the effect? 



Exercise 4. Tear off a portion of the skin from the fleshy part of an 

 onion. Soak in eosin and examine under the microscope. Note the cell 

 walls, protoplasm, nuclei and vacuoles. 



Exercise 5. Examine the cells of a very young leaf of Elodea cana- 

 densis (which is a common water weed) under the compound microscope. 

 Note the shape of the cells, cell walls, cell-contents and general appearance 

 of the cells. Give special attention to the protoplasm, nucleus and chloro- 

 plasts. Does .the protoplasm move? 



Exercise 6. Examine the hairs from the very young, actively growing 

 stem of a Petunia or from the stamens of any wild or cultivated species of 

 Tradescantia. Note the number, form, size and shape of the cells; the 



