A STUDY OF AUTUMN WEEDS 



aaa Leaves, at least basal ones, deeply cut 



b Seed pods numerous, small, lozenge-shaped, and 



peppery to taste 

 bb Seed pods numerous, heart-shaped, flattened 



(Fig. 3/0 

 bbb Seed pods not as above 



c Leaves cut into linear lobes 



d Flowers yellow, cruciform (see Fig. 39) 

 e Leaves sweet-scented but with very 

 bitter taste; flower clusters in leaf 

 axils 

 ee Leaves with strong, unpleasant odor; 



flower clusters at end of branches 

 cc Leaves merely irregularly cut, not in linear 

 lobes 



d Flowers in heads 



dd Flowers not in heads, yellow, cruciform 

 e Flowers \ inch across; seed pods with 

 long beak 



/ Basal leaves lance-shaped 

 ff Basal leaves reverse lance-shaped 

 ee Flowers^ inch across; pod four-angled 

 eee Flowers | inch across ; pod round and 

 hairy 



Other species occur, but usually not as 

 weeds (see Gray, p. 426) 



Pepper Grass 

 Shepherd's- Purse 



Wormwood 

 Ragweed 



Oxeye Daisy 

 The Mustards 



Charlock 

 White Mustard 

 Black Mustard 



Hedge Mustard 



A study of a single weed. Select some weed with good-sized flowers, 

 like bouncing Bet, Jimson weed, evening primrose, or wild mustard. 

 First, examine the whole plant out of doors and notice the parts root, 

 stem, leaf, blossom, and fruit. Dig out the plant to see the extent of the 

 root system. Sweet clover is a good weed to try this on for comparison, 

 for the roots are tough and may be readily traced. Moreover, on its roots 

 are often found those nodules of nitrifying bacteria so characteristic of 

 the legumes. Some member of the class should look up and report on such 

 plants and their use. Write out an abstract of this report. 



Cut a cross-section of the stem and see the ring of fibro vascular bundles. 

 These are particularly well shown in the leaf stem of another weed, plantain. 

 Let each pupil break this stem and see how tough the stringy, fibrovascular 

 bundles are. Take hold of one and pull it out; note how it runs up into 

 the leaf, branching and forming a conspicuous part of the leaf vein. Draw 

 the leaf stem to show the fibrovascular bundles. 



Flower. In the wild mustard note the four sepals on the outside of 

 the flower at its base. Altogether they constitute the calyx. Within these 



