A MANUAL OF BOTANY 25 



form of stem ? Obtain a garden catalogue and observe the 

 names of many, bulb-bearing plants, common in the garden 

 either as vegetables or flowers. 



Why do early spring flowers commonly have some form 

 of underground stem, — bulb, tuber, or rhizome, — or else 

 have flesliy roots? (See rhizomes.) 



Experiential applications. Onions, gladioli, tulips, and lilies 

 grow into large bulbs. All are grown in immense quantities 

 for food or for flowers. How would you proceed to produce 

 the bulbs themselves of the largest size for purposes of sale ? 



Onions, shallots, leeks, garlic, chives, are all bulbs. How 

 do they differ ? In how many ways may the first be grown ? 

 What will an acre of onions yield in bushels and money ? 

 What are Bermuda and Spanish onions ? 



Grind up a large onion, place pulp in strong cotton bag on 

 an inclined board with grooves leading to a common outlet. 

 Cover with another board, on which place as great a weight 

 as possible. Collect all the juice. Allow to stand for 24 

 hours. You will find oil and ivater. Which is on top ? Sepa- 

 rate by a pipette. You are an oil producer. 



5. jVItscellaneous Stems 



Kinds named. Cacti plants and stems of scouring rushes 

 ought to be obtained to show stems particularly modified to 

 do the work ordinarily done by other plant parts. Grass 

 stems in long section and the compound thorns of honey 

 locust and the simple thorns of hawthorns show other stem 

 modifications of importance. 



Study. Study carefully each stem furnished. Observe 

 its peculiarities of form and structure and make drawings 

 showing all peculiar features. 



What part of the ordinary plant is green ? What color 

 have the cacti and scouring rush stems ? Do these stems 

 have leaves as commonly understood ? Keep this in mind 



