ON THE GROWTH OF PLANTS. 



23 



Hence, then, in as far as the economics of the question are concerned, we 

 may safely conclude that the sowing of dirty flax-seed at any price is disad- 

 vantageous, and this not only that the resulting crop, if not quite ruined, is 

 certain to be diminished in quantity and injured in quality, but, as ill weeds 

 <*row apace, all the sorts growing with the flax had sown much of their seeds 

 before the flax-seed itself had ripened, so that a succession of weeds is by this 

 means entailed upon the farm from generation to generation. 



As regards the plot with dodder, the object of sowing these together was 

 for the purpose of observing with my Class the manner in which the parasite 

 became attached to its foster-parent, and I therefore offer the following 

 remarks upon the growth of the Cuscuta epiliiium, not as containing any new 

 results, but as offering an example of the kind of experiments followed out 

 in my botanical garden. 



In about four days after the seed of the dodder was sown, a few whitish 

 thread-like germs of about Fig. 1. Fig. 2. Fig. 3. 



three lines in length were 

 seen protruding from the 

 soil, some of these being 

 quite free, others crowned 

 with the seed testa. Three 

 days afterwards the flax 

 came up, and the dodder 

 might then have been seen, 

 as in the accompanying 

 fig. 1, bending its germ 

 towards a flax-plant ; by 

 this time it has doubled 

 in length ; and if the flax- 

 plant be far away, it seems 

 to be endowed with the 

 power of growing to as 

 much as an inch in length 

 in order to reach it, whilst 

 in experiments of dodder 

 seed sown by itself, the 

 germs were always short 

 and soon withered ; but on 

 inserting other plants in 

 the same pot, they became 

 attached to them, &s Radish, 

 Tomato, Groundsel, and 

 Chickweed were all in this way attacked by the dodder amongst which 

 young plants were inserted; and in one case, where a pot of growing flax 

 dodder was placed near a Sedum in my conservatory, the latter was attacked, 

 and the dodder grew upon it most vigorously. 



In a short time afterthe germination of the dodder and the flax, the 



