PREPARATION OF SPECIMENS OF OPUNTIA. 28 1 



One can, in the majority of species, avoid the spines very nicely 

 by choosing his method of grasping the joint, but it is very diffi- 

 cult to keep away from the spicules if the joints are touched at 

 all. A few thicknesses of paper or one thickness of pasteboard 

 doubled in the left hand will enable one to handle almost any 

 species with impunity. 



Both young and fully matured joints should be put up when 

 possible. The young joints in the growing season will show the 

 leaves beautifully and these should always be preserved. The 

 young joints for several weeks after growth begins are very 

 tough and leathery, making it a very difficult task to split them 

 neatly. Experience and a long knife blade to enable one to keep 

 away from spines and spicules which are very easily separable 

 at this time, are the only requisites to success. No scraping is 

 necessary with these for they usually dry without scraping as 

 quickly as the older joints do after being scraped. 



When possible, it is a good plan to leave the prepared joints 

 to dry in the sun for several hours before being put in press. 

 They can then be subjected to heavy pressure for about twelve 

 hours. When the driers are first changed the cut surfaces are 

 firmly attached to the papers. This prevents rapid evaporation 

 of moisture. The joints should, therefore, be loosened from the 

 sheets each time the driers are changed until the cut surface 

 becomes dried so that it will not stick. After being under heavy 

 pressure until well shaped, the specimens may then be placed for 

 a time between driers wdthout pressure, but when they begin to 

 buckle and curl the pressure should be restored again. I often 

 find it convenient, especially when in a hotel or other room at 

 night, to take my Opuntia specimens out of the press entirely 

 and spread them over the floor to dry, as they \;ill at night, 

 placing them under a heavy pressure again in the morning. 



But all this relates to joints alone. Flowers and fruit must 

 also be preserved if they are to be found. The flowers of Opuntia 

 may be made into specimens as successfully as almost any of our 

 large and showy flowers. The only difficulties involved consist 

 in determining how best to prepare them so as to show the maxi- 

 mum of characters upon a flat surface. Very successful floral 



