On the Orobanche and Prunella vulgaris. 



175 



As the above observations are of some importance to farmers^ 

 and particularly to seedsmen^ to whom the possession of a pure 

 stock of seed is of so much value, I have taken the liberty of lay- 

 ing- them before you. 



And, with much respect, remain, 

 Sir, 



Your obedient Servant, 



James Main. 



3, Elm Terrace^ Fulham-road, 

 April 25, 1839. 



Note by the Rev. W. L. Rham. 



Mr. van Aelbroeck, of Ghent, in his excellent work ' On the 

 Practical Agriculture of Flanders,' states the following experi- 

 ment on the orobanche : — 



" Having chosen a few perches of land, where neither clover nor 

 orobanche had grown for 10 years previously, I had it trenched 

 1 5 inches deep, that, in case any seeds of orobanche should acci- 

 dentally have been there, they might be buried beyond the reach 

 of the roots of the clover ; for, unless it meets with these, the seed 

 of the orobanche does not germinate. I concluded that the sur- 

 face-soil was perfectly cleared of the seeds of this weed. 



The next point was to clear the clover -seed to be sown of any 

 seed of orobanche. The mode I adopted was as follows :— -In 

 the month of September of the preceding year I had procured 

 some seed of orobanche ; I mixed this with clover-seed, and then 

 examined some of it with a microscope, /or the seed of the oro- 

 banche is too small to he distinguished in the mixture by the naked 

 eye. I saw that the seed of the orobanche adhered to the clover- 

 seed by means of a glutinous substance w hich is on its surface. I 

 divided the mixed seed into two equal parts, and to one of these 

 I added a fourth part of wood-ashes. I rubbed this well in my 

 hands in order to detach the seed of the orobanche from the clo- 

 ver-seed : I then threw it into a bucket of water, stirring it with 

 my hands for some minutes, and let it settle. The orobanche- 

 seed, ivhich is as light as the finest dust, mixed with the ashes, 

 and v/as gently poured off with the water. The clover-seed, which 

 remained at the bottom, was again washed two or three times with 

 pure w ater, and then poured upon a sieve, and there again washed, 

 by pouring water over it while it was stirred with the hand. I 

 was now persuaded that all the orobanche-seed had been washed 



