Bull Thistle (C. lanceolatum, la. general.) 

 2. Head not spiny but sticky. 



a. Leaves not hairy or sparingly ; in swamps Marsh 



Thistle (C. muticum, N. la. rare.) 

 a. Leaves hairy at least below. 



Heads very large ; in swamps Iowa Thistle ( C. 



iowense, meadows, la. general.) 

 Heads smaller; in woods Wood Thistle (C. altis- 



simum, E. la.) 



The C. of the Sunflower family (Compositae), stands for the 

 genus Cirsium, which includes all of the true thistles. There are 

 other so-called thistles but the botanical name should only be 

 applied to the plants of this genus. The Russian thistle is not 

 a true thistle but belongs to the Goosefoot Family (Chenopo- 

 diaceae. ) The student should early recognize that certain plants 

 belong to some particular family and with a little practice such 

 plants as the sunflower, aster, goldenrod, purple cone flower, 

 may weed, and dandelion, will readily be recognized as belonging 

 to the composite family. 



To facilitate the work of the teacher I have added a few ques- 

 tions which the student should answer. If the teacher is not 

 familiar with the terms that are here used, any of the larger 

 dictionaries will assist in getting the definitions, sepals, petals, 

 stamens, pistils, bracts, ray flowers, achene, etc. Simple leaves 

 may be linear, hastate, halberd, cordate, acute, acuminate, cleft, 

 lobed, dissected, and sagittate. Compound leaves may be pin- 

 nate (rose), and palmately (horse chestnut) compound. Fruits 

 may be berry (black nightshade, horse nettle), capsule (Jimson 

 weed), pod (clover and sweet clover), achene (sunflower, thistle), 

 caryopsis or grain fruit (corn, wheat, crab grass). Flowers, 

 regular (morning glory, strawberry), irregular (sweet clover, 

 sweet pea), polypetalous (crowfoot, clover), gameopetalous 

 (morning glory, horse nettle), apetalous (smartweed), calyx col- 

 ored like petals (smartweed.) 



QUESTIONS AND TOPICS. 



1. Describe accurately in your own language the chief points 

 of the following weeds: Greater or giant ragweed, dandelion, 

 quack grass, burdock, velvet weed, dock, parsnip, cocklebur and 

 other weeds mentioned in the Iowa weed law. 



2. Note the methods of reproduction in the following weeds : 

 Canada thistle, dock, quack grass, foxtail, burdock, bull thistle, 

 cocklebur, horse nettle, velvet weed. 



3. Note the difference in the underground parts of the fol- 

 lowing weeds: Morning glory, quack grass, milkweed, sheep 



