92 AGKONOMY 



being misunderstood. Each species has a specific name con- 

 sisting of a single word, which is applied to it much as the 

 given names of people are applied to them. Such specific 

 names as alba, "white "; rubra, "red "; and vulgare," common," 

 are frequently used. The generic name, always written before 

 the specific, shows to what larger group a species belongs. 

 Thus the crimson clover is Trifolium incarnatum. The red 

 clover is also a species of Trifolium called Trifolium pratense. 

 Only one species in each genus can have the same specific 

 name, though this may be used again and again in other 

 genera. Alba is a common specific name for white-flowered 

 species in many genera. The generic name, however, can be 

 used for but one group of plants. There is but one genus 

 Trifolium in all the world. In naming lesser divisions of a 

 species it is customary to give them varietal names taken 

 from the Latin or Greek, though in many cases such plants 

 are named after prominent persons, gardeners, and the like. 



PRACTICAL EXERCISES 



1. Strip off a piece of epidermis from one of the scales of an onion 

 bulb, mount, and examine with the microscope. Find and label all parts 

 of the cell mentioned on page 57. In the cells of ditch moss or the hairs 

 from the flowers of gloxinia or tradescantia, note the circulation of the 

 protoplasm. 



2. Make thin sections of a potato and examine in the same way, to 

 see starch grains. Apply a drop of dilute iodine solution to a piece of 

 laundry starch. Note the color. Test the mount of potato in the same 

 way. 



3. Mount a leaf of the ditch moss (Elodea) or a leaf from any of 

 the broad-leaved true mosses and note the chloroplasts. 



4. Mount thin sections of the carrot or orange peel and examine 

 the chromoplasts. Make a similar mount of the epidermis from the 

 underside of a nasturtium petal. 



5. Soak seeds of radish or mustard for a short time and throw them 

 against the inside of a clean moist flowerpot to which they will stick. 

 Invert the flowerpot over a shallow dish of water for a few days and 



