28 



WEEDS OF FARM LAND 



Experiments have shown that large numbers of weed seeds 

 retain their power of germination and growth even after they 

 have passed through the digestive tracts of animals (see p. 74). 

 As animals often traverse long distances in a comparatively 

 short time they are able in this way to accomplish a good deal 

 of seed distribution, and may on occasion be responsible for 

 the introduction of a weed into a fresh locality. 



(e) Fruits and Seeds 

 Distributed by Birds. 

 Birds may either carry 

 seeds about on their feet, 

 feathers or bills, or they 

 may eat them for food and 

 void a certain proportion 

 uninjured. Ducks, water 

 hens, and other birds have 

 been proved to carry 

 species of water plants 

 from one piece of water 

 to another by means of 

 wet seeds or pieces of the 

 actual plant sticking to 

 them. Creeping butter- 

 cup (Ranunculus repens] 

 often occurs on the damp 

 edges of ponds and is 

 known to be carried about 

 by ducks and water hens. 1 

 Enormous numbers of 



FIG. 12. SHEPHERD'S NEEDLE (Scandix 

 pecteri), showing the Small Flowers and 

 much Elongated Fruits. 



weed seeds are eaten by 

 wild birds, and though it 

 is usually assumed that 

 all such seeds are destroyed this is not the case. Collinge's 2 3 

 experiments have shown that birds are in this way responsible 

 for the distribution of many common weeds, including ribwort 

 plantain, mouse-ear chickweed, groundsel, sheep's sorrel, daisy, 

 yarrow, creeping buttercup, dandelion, chickweed, charlock, 

 dock, knotgrass, goosegrass, and various others. From the 



1 Woodruffe Peacock, E. A. (1917), " Means of Plant Dispersal," Selborne 

 Magazine, XXVIII, pp. 80-83, 97-101, 114-116; (1918), XXIX, pp. 9-12. 



2 Collinge, W. E. (1913), " Destruction and Dispersal of Weed Seeds by Wild 

 Birds," Jouvn. Bd. Agric., XX, pp. 15-26. 



3 Collinge, W. E. (1914), " Some Further Observations on the Dispersal of 

 Weed Seeds by Wild Birds," Journ. Econ. Biology, IX, pp. 69-71. 



