hairs), which are hooked, as shown in Pig. 4. is enabled to 

 cling to the fleece of animals mid clothes of persons, arfd thus it 

 is often carried great distances. Birds aid also in disseminating 

 of weeds, by tin- mud containing seeds which clings to their feet, 

 and by eating of seeds, which pass through the digestive appa 

 ratus and are still capable of germinating. The water acts 

 principally in a mechanical way by carrying the seeds of weeds. 



The writer has often svcw Tumble-weeds, Pig-weeds, Thistle 

 akenes on the surface of tlie snow which were drifting before the 

 wind, and when the snow melts in the spring these seeds ami 

 fruits arc often carried still further by the water. 



Certain fruits. Touch-me-nots. ImpatieriS, Wood Sorrels, Ox- 

 alis, etc., burst when the pod is touched, thus scattering the 

 Seeds for several feet. 



Fig. 5. Small nutlets of Echinospermum 

 lappula, after Sud worth in Real's Grasses 



Fig. 6. Daucus arota. a. Whole fruit with 

 prickles, h. Cross section, after Sudworth in 

 Seal's Grasses of N. A. 



IMPURITIES IN SEEDS. 



Prof. Lazenby found in Michigan Amber wheat sent out by 

 the Department of Agriculture for 1884, the following impuri- 

 ties: Chess, Bromus secalinus, 9,248 seeds per bushel, an estimate 

 made upon the amount found in one quart: Corn Cockle, Lychnis 

 g'dhago. 1,888; Oat, Avena sativa, 160; Barley, Hordeum jubatum, 

 32: Snow Thistle, Sonchus, 32. 



Many of our most troublesome weeds are introduced in this 

 way. such as the Corn Cockle, Wild Oat, Avena fatua. etc. 



It is well known that railroads are a great factor in the dis- 

 tribution of pernicious weeds. One or two cases will suffice. 

 Squirrel-tail grass, Hordeum jubatum, was not known to occur in 

 this region until last summer when it was found for the first 

 time along the C. M. & St. P. railroad. Common Flax. Lin ma 

 usitatissimum, L, is commonly found along railroads where the 



