126 MANUAL OF NATURK STUDY. 



this weed began to work its way along these trails 

 toward the Mississippi. 



*' The fruit, a berry, is covered by a very prickly 

 calyx, and easily adheres to the tails of horses and 

 cattle very much like cockle-burrs. Now the weed 

 is found abundantly along the main roads as far 

 east as central Missouri. 



" In general the migration of our weeds has been 

 westward, but the Solanum rostratum is a notable 

 exception to the rule. 



"D. L. K." 



What seeds are distributed by the wind ? Pupils 

 will name dandelion, iron-weed, goldenrod, milk- 

 v/eed, thistle and others. What seeds are distribu- 

 ted by water ? Nuts of various kinds. Cocoanuts, 

 for example, have been carried from island to island 

 in that wa}'; also algae and ofiF shoots from weeds of 

 lake and ocean. Many seeds are carried down 

 rivers and creeks at time of great freshets and dis- 

 tributed along the low submerged lands. Another 

 way of distribution consists in the manner of sep- 

 aration from plants, as described in (2) of this year's 

 course. 



4. Show how seeds escape from the ovary. See 

 (2) of this year's work. 



5. Show how seeds are protected through the 

 winter. 



Berries, nuts, grapes and all indehiscent fruits 



