igS 



BIOLOGICAL LECTURES. 



of the flowering stalks have been neatly cut away, in order the 

 better to show those that remain. Of these one has had its 

 maturing fruit cut transversely, another longitudinally. But 



even here we do not stop; 

 for, taking advantage of the 

 original large size of the 

 plant, we have it cut in half, 

 and the interwoven humus 

 roots are thus exposed. 



Suppose, again, we wish 

 to set out in two bottles sta- 

 minate and pistillate branches 

 of the maiden-hair tree {Gink- 

 go biloba), or, as shown here, 

 of the Honey-Locust {Gledit- 

 schia triacanthos). To expose 

 the inflorescences properly, 

 most or all of the leaves 

 should be removed to a greater 

 or less extent ; though the 

 retention of the petioles is 

 important, from their mor- 

 phological relation. 



Still more elaborate prep- 

 aration may be desirable. 

 For example, to represent 

 the growth-phases of seed- 

 lings, an excellent plan is to 

 tie these side by side on a 

 sheet of mica with white silk 

 thread passed through small 

 holes in the sheet. In this 

 way the relative development 

 of primary, secondary, or adventitious roots, the time of ap- 

 pearance on these of root tubercles in leguminous species, the 

 swelling up of root or stem as a storing center in other plants, 

 can all be illustrated. But skill and patience alike can be 

 displayed over flower parts, and once set out, these remain as 



Fig. 4. 



