234 APPENDIX 



for study. Seeds, bull)S, and rootstocks in great variety can be had of 

 the seedsmen, and much useful material may he found among the fruits 

 and vegetables sold by marketmen or provision dealers all the year 

 round. Dealers in fine lumber and cabinet woods can supply many kinds 

 which are of histological interest. 



4. Collection of material at the proper season. In many cases the useful- 

 ness of material depends largely on its being collected at just the right 

 stage of maturity or at some particular season. Experience will show 

 the instructor at what time he can in his special locality best lay in the 

 stock for his year's work. A few examples only need here be mentioned. 

 Green corn (best of the large " dent " variety), just passing out of the 

 milky condition, should be collected and boiled in water for about 

 twenty minutes. It is then to be sliced from the cob, cutting deeply 

 enough to preserve the embryos uninjured. The grains thus prepared 

 may be preserved in alcohol indefinitely for study of the entire embryo. 



Bean fruits of all ages, from the newly fertilized pistil to the fully 

 developed but not dry pod, should be collected in season and put in 

 preservative fluid, such as formalin, to illustrate the development of a 

 fruit. If convenient, series of stages in the development of other fruits, 

 e.g. apple, strawberry, orange, should be secured. 



Indian corn plants should be dug up at various stages of growth and 

 the lower part of the stem, with the attached roots, dried and preserved, 

 after being thoroughly washed. These will illustrate secondary roots 

 and successive steps in the formation of aerial roots. Pieces of corn 

 stem of various ages show the development of bundles and of the very 

 hard sclerenchyma of the rind. 



Bits of Arktolochia or other stem used to illustrate open bundles 

 should be collected in early summer, as soon as these are found to be 

 well developed. A series of such stems cut at short intervals through- 

 out the growing season is valuable. 



Leaves of deciduous trees or shrubs should be collected as soon as 

 fully grown and again when about to fall, and preserved in alcohol 

 for the study of translocation of starch before falling. 



Series of herbarium sheets and of specimens in preservative fluid 

 should be secured to show the seasonal cycle of such plants as Erythro- 

 nium, Sanguinaria, and many similar forms. 



5. Field work. Many botanical topics can best be taught and some 

 can only be taught in the field. It may be found desirable to interweave 



