Appendix—Syllahus of Laboratory Work. 285 



Development of plantlets (44-46). Devote several ex- 

 ercises to a study of the development of plantlets of 

 the bean, pea, wheat, Indian corn, pumpkin, etc. To 

 furnish the plantlets, seeds of the different sorts should 

 be planted on several successive days, beginning at 

 least 10 days in advance. 



Not all seeds should he deeply planted (47). Plant 

 seeds of the bean, pea, Indian corn and wheat in 6-inch 

 flower pots, at three different depths, viz., 1/2 inch, 3 

 inches and 6 inches from the bottom; place the pots in 

 a warm place for 3 weeks, after which carefully re- 

 move_ the soil, noting the germination of the seeds in 

 the different layers. 



Vigor of plantlet proportionate to size of seed (48). 

 Plant large and small specimens of navy beans by them- 

 selves, in greenhouse saucers, and permit them to ger- 

 minate. The smaller seeds usually germinate earlier 

 than the larger, but they produce more slender plant- 

 lets, which soon fall behind the others in development. 



Plantlet visible in the seed (53). Boil samples of 

 various kinds of seeds until they are fully swollen, 

 after which require the students to dissect them and to 

 seek out the plantlets. Lenses, needles and forceps are 

 very useful in this work. 



2^he cotyledons a storehouse for food (59). Remove 

 the cotyledons of some bean plantlets growing in a 

 flower pot or saucer, leaving those of other plantlets 

 intact. After a week note the result in the checked 

 growth of the mutilated plants. 



Vascular bundles (67). Study these as shown in the 

 stalk of Indian corn, in the leaf stems of various plants 

 and in the leaf sears on the stems of plants. 



Cambium layers (68). Locate this in sections of 

 various dicotyledonous stems, including the potato tu- 

 ber; also note the absence of the cambium layer in 

 monocotyledonous stems. 



Boot-hairs (100). Study these as illustrated when 

 seeds germinate in the seed tester. Germinated radish- 

 seeds, left in the seed tester two or three days, usually 

 develop root-hairs in great abundance. Also search out 



