COLLECTING AND PRESERVING CHAROPHYTA. 93 



the plant by its roots (when the root has been secured) 

 and drawing it from right to left and left to right through 

 the water for a few moments. Then hold it up till as 

 much water as possible has run off. 



It should be laid straight out on a piece of paper or 

 calico of suitable size, wrapped up, and placed at once 

 in the vasculum to avoid exposure to the air. The 

 water which collects gradually in the vasculum must 

 from time to time be drained ofE, otherwise the plants 

 will become sodden and injured. 



The preparation of specimens for the herbarium is not 

 quite easy, but few plants better repay a little care and 

 pains in pressing and drying. 



Charas can sometimes be pressed without floating 

 out, though few specimens can be gathered in such 

 condition that they will not require some amount of 

 washing at home. The Nitelleae should always be 

 floated out in the same way as Algge — ^that is, a sheet 

 of paper placed in a pan of water, and the plant (after 

 having been washed) placed on it, and arranged as 

 naturally as possible with the fingers or a brush. The 

 shallow " baths " used by photographers are excellent 

 for the purpose, but an oblong, white enameUed-iron 

 or zinc tray about 2 inches deep is equally serviceable and 

 more portable. Failing either of these, a large dish or 

 basin may be used. A sheet of perforated zmc laid 

 under the paper will be found of great assistance in 

 removing the specimens from the water. Good, firm 

 white printing paper should be used for fioating the 

 specimens upon. In the case of dioecious species the 

 sexes should, if possible, be kept apart and either placed 

 on separate sheets of paper, or perhaps preferably a 

 specimen of each placed side by side on the same 

 sheet. 



When the specimen has been removed from the water 

 it should be drained, and a piece of thin calico or linen 

 (previously washed free from dressing) should be placed 

 over it to prevent its adherence to the drying-paper. 

 The calico should be removed when the drying-paper 



