PLANT PROBLEMS 75 



5. Discuss the advisability of having foreign seeds and grains in- 

 spected before being allowed to enter this country. 



6. Discuss the advantage of smothering weeds with quick-growing, 

 thickly seeded crops, like red clover anol rye. 



7. Test the germinating power of a weed by placing its seeds on damp 

 blotting paper between two plates. 



8. Record instances observed of weeds damaging food plants. What 

 did Darwin mean by the ** struggle for existence " and " survival of the 

 fittest " ? (Ref . : Hodge, M Nature Study and Life," chap, vii.) 



Copy the following list of poisonous plants into your notebook, and 

 make the acquaintance of each one, if possible, during outdoor tramps. 

 Increase the list by wider observation. 



Poison ivy Rhus radicans [poison oak, three-leaved ivy, mercury, 

 black mercury, markweed, pikry (Maine)]. 



Poison sumac Rhus vernix [swamp sumac, dogwood (Massachu- 

 setts), poison elder (Alabama), poison ash (Vermont), thunderwood 

 (Georgia, Virginia)]. 



Poison oak Rhus diversiloba [poison ivy, yeara, California poison 

 sumac]. 



Poison hemlock Conium maculatum [hemlock, wild hemlock, spotted 

 parsley, stinkweed, poison root, poison snakeweed, cashes, wode-whistle]. 



Water hemlock Cicuta maculata [spotted parsley, snakeweed, beaver 

 poison, musquash root, muskrat weed, cowbane, spotted cowbane, chil- 

 dren's-bane, death-of-man]. 



Pokeweed Phytolacca decandra. 



Corn cockle Agrostemma githago. 



Black cherry Prunus serotina [wild cherry, rum cherry]. 



Red buckeye and common horse-chestnut ^Esculus pavia and 

 hippocastanum. 



Broad-leaf laurel Kalmia latifolia [laurel (north of Maryland), ivy 

 (south of Maryland), mountain laurel, sheep laurel, poison laurel, wood 

 laurel, small laurel, high laurel, American laurel, poison ivy, ivy bush, 

 ivy wood, big ivy, calico bush, spoonwood, kalmia, wicky]. 



Narrow-leaf laurel Kalmia angusti folia [sheep laurel, lambkill, sheep 

 poison, lamb laurel, small laurel, low laurel, dwarf laurel, wicky]. 



Jimson weed Datura stramonium and D. talula, the taller and 

 purple-flowered species [Jamestown weed, common stramonium, thorn 

 apple, apple of Peru, devil's apple, stinkwort, stinkweed, Jamestown lily, 

 white man's plant (by the Indians)]. 



