160 Retrograde Varieties 



Paper bags also may be made use of. They 

 are slipped over the flowering branches, and 

 bound together around the twigs, thus enclosing 

 the flowers. It is necessary to make use of 

 prepared papers, in order that they exclude 

 rain or wind. The best sort, and the one that I 

 use almost exclusively in my fertilization-ex- 

 periments, is made of parchment paper. This 

 is a wood-pulp preparation, freed artificially 

 from the so-called wood substance or lignin. 

 Having covered the flowers with care, and hav- 

 ing gathered the seeds that are free from other 

 intermixtures and if possible separately for 

 each single individual, it only remains to sow 

 them in quantities that will yield the greatest 

 possible number of individuals. Reversions are 

 supposed to be rare and small groups of seed- 

 lings of course would not suffice to bring them 

 to light. Only sowings of many hundreds or 

 thousands of individuals are decisive. Such 

 sowings can be made in one year, or can 

 be extended over a series of years and of gen- 

 erations. Hildebrand and Hoffman have pre- 

 ferred the last method, and so did Hof- 

 meister and many others. Hildebrand sowed 

 the white hyacinth, and the white varieties of 

 the larkspur, the stock and the sweet pea. Hoff- 

 man cultivated the white flax and many other 

 varieties and Hofmeister extended his sowings 



