PLANTS. 75 



field to another, will produce scattering kernels in the 

 latter Held of the variety contained in the Tornier. 



QUESTIONS. 



^Y[mt arc plants? What are the two essential parts of a seed? 

 What is the eniljryo? How long will seeds preserve their vitality? 

 Why should new seeds be used for planting? What is the effect 

 of planting unripe seeds? W^hat is the effect of selecting the best 

 specimens of seeds for planting? 



What are the three comlitions necessary ft>r the growth of seeds? 

 How much moisture is most favorable? What is the effect of 

 planting seeds in soil either too warm or too colt? What is the 

 effect of planting seeds too early in the spi-ing ? Why will seeds 

 fail to grow where there is no air ? Uniler what cireumstances is 

 it best to plant seeds deeply? When is it better to eover them but 

 lightly ? AVhat causes weeds to spring up after ground lias been 

 plowed? Why have these weeds failed to grow before ? 



What are the three processes involved in germination ? Why must 

 the seed be filled with moisture ? Why is grain allowed t(j sprout 

 in making malt? Why does sprouting produce heat? 



What are the radicle and the plumule? Why do they stai-l from the 

 seed in opposite directions? Which is more essential to the plant, 

 the atmosphere or the soil? In what jjoints do plants, in their 

 growth, resemble animals ? 



Name the elementary substances that are essential to the growth of 

 plants. AVhat food do i)lants obtain largely from the atmosphere ? 

 Explain the process by which it is obtained. W^hat has the sun- 

 light to do with it ? Why do plants become pale in dark weather? 

 How do i)lants purify the air ? Do they remove oxygen from tlie 

 air? Do they purify the air in the night? Are they beneficial to 

 the air in a dwelling-house ? How are drooping plants revived by 

 watering? Do plants obtain nitrogen from the air? 



What are the purposes of roots? Name some plants which have tap- 

 roots ? By what method do roots grow ? How many roots have 

 plants? How deep do they sometimes extend? 



Name all the elements of food that plants obtain from the atmos- 

 phere. Name those that they obtain from the soil. How do they 



